A drying system for canisters loaded with spent nuclear fuel

Abstract

The present invention relates to a drying system for a canister loaded with spent nuclear fuel, the purpose of which is to rapidly dry the interior of the canister to meet required requirements while simultaneously verifying the drying state in real time, and to detect the radiation dose rate for water and air during the execution of the drainage and depressurization drying process, and to determine whether the spent nuclear fuel cladding is damaged by performing radionuclide analysis on water samples and air samples when a preset radiation dose rate is detected. The configuration comprises: an air distribution device having first to fifth connectors and a pressure gauge mounting hole (20f), which serves as a distribution means for controlling the air flow path, wherein the first connector is detachably connected to the exhaust port of the canister so as to be connected to the inner hollow of the canister; and first to fifth solenoid valves each mounted on the first to fifth connectors of the air distribution device and opening and closing the first to fifth connectors. A pressure sensing means mounted in a pressure gauge mounting hole of the air distribution device to detect the internal pressure of the canister and transmit the pressure sensing value; a non-reactive gas supply tank having an exhaust port in which non-reactive gas is stored, connected in communication with the second connector of the air distribution device through a gas supply pipe, and supplying and stopping the supply of non-reactive gas into the canister through the air distribution device according to the opening and closing operation of the second solenoid valve so that non-reactive gas is filled into the empty space where water in the canister is drained; a radionuclide analysis device equipped with a sample analysis chamber in which a collected sample is filled and a radionuclide analysis unit for analyzing radionuclides among the sample in the sample analysis chamber, and for analyzing radionuclides in the collected air and water samples among the air and water discharged from the exhaust port and drain port of the canister; and a primary pressure reduction exhaust pipe connected in communication with the third connector of the air distribution device and exhausting the air in the canister to the exhaust system; A sixth solenoid valve mounted on the exhaust system-side end of the primary pressure reducing exhaust pipe and opening and closing the exhaust system-side end of the primary pressure reducing exhaust pipe;A primary pressure reducing pump mounted on the primary pressure reducing exhaust pipe between the third and sixth solenoid valves and pumping air inside the canister to be exhausted into the exhaust system through the primary pressure reducing exhaust pipe; a first radiation dose rate detection means mounted on the primary pressure reducing exhaust pipe between the third solenoid valve and the primary pressure reducing pump and detecting the radiation dose rate of the air exhausted into the exhaust system along the primary pressure reducing exhaust pipe in real time and transmitting the detected value; a first air sample collection tube branched to communicate with the primary pressure reducing exhaust pipe between the sixth solenoid valve and the primary pressure reducing pump, connected to communicate with the inlet of the sample analysis chamber of the radionuclide analyzer, and supplying an air sample collected from the primary pressure reducing exhaust pipe into the sample analysis chamber of the radionuclide analyzer; and a seventh solenoid valve mounted on the first air sample collection tube and opening and closing the first air sample collection tube; A secondary pressure reducing exhaust pipe connected to communicate with the fourth connector of the air distributor device and exhausting air inside the canister into the exhaust system; an eighth solenoid valve mounted on the exhaust system-side end of the secondary pressure reducing exhaust pipe and opening and closing the exhaust system-side end of the primary pressure reducing exhaust pipe; a secondary pressure reducing pump mounted on the secondary pressure reducing exhaust pipe between the fourth and eighth solenoid valves and pumping air inside the canister to be exhausted into the exhaust system through the secondary pressure reducing exhaust pipe; and a second radiation dose rate detection means mounted on the secondary pressure reducing exhaust pipe between the fourth solenoid valve and the secondary pressure reducing pump, detecting the radiation dose rate of the air exhausted into the exhaust system along the secondary pressure reducing exhaust pipe in real time and transmitting the detected value; A second air sample collection tube that branches off to communicate with the secondary pressure exhaust pipe between the eighth solenoid valve and the secondary pressure pump, is connected to communicate with the inlet of the sample analysis chamber of the radionuclide analyzer, and supplies an air sample collected from the secondary pressure exhaust pipe into the sample analysis chamber of the radionuclide analyzer;A ninth solenoid valve mounted on the second air sample collection tube and opening and closing the second air sample collection tube; a drain pipe detachably connected to the drain port of a canister and draining water filled in the canister into a drainage system; tenth and eleventh solenoid valves each mounted on both ends of the drain pipe and opening and closing both ends of the drain pipe; a drain pump mounted on the drain pipe between the tenth and eleventh solenoid valves and pumping and draining water filled in the canister; a third radiation dose rate detection means mounted on the drain pipe between the tenth solenoid valve and the drain pump, detecting the radiation dose rate of the water drained along the drain pipe in real time and transmitting the detected value; and a water sample collection tube branched out to communicate with the drain pipe between the eleventh solenoid valve and the drain pump, connected to communicate with the inlet of the sample analysis chamber of the radionuclide analyzer, and supplying a water sample collected from the drain pipe into the sample analysis chamber of the radionuclide analyzer. A 12th solenoid valve mounted on the water sample collection tube and opening and closing the water sample collection tube; a wash water supply tank having a drain port in which wash water is stored, which supplies wash water into the primary and secondary pressure reduction exhaust pipes and the drain port to perform washing; a first wash water supply pipe branched to communicate from the drain port between the 10th solenoid valve and the third radiation dose rate detection means, and connected to communicate with the drain port of the wash water supply tank to supply wash water into the drain port; a 13th solenoid valve mounted on the first wash water supply pipe and opening and closing the first wash water supply pipe; and a wash water supply pump mounted on the first wash water supply pipe between the wash water supply tank and the 13th solenoid valve and pumping wash water within the wash water supply tank; A second washing water supply pipe that is branched out to communicate from the first washing water supply pipe between the washing water supply pump and the 13th solenoid valve, and is connected to communicate with the 5th connector of the air distribution device (20) to supply washing water into the first and second pressure reduction exhaust pipes;The system is characterized by comprising: a control unit that is respectively connected to the pressure sensing means, the first to third radiation dose rate detection means, the radionuclide analysis device, the first and second pressure reducing pumps, the drainage pump, the wash water supply pump, and the first to thirteenth solenoid valves, and controls the operation of the first and second pressure reducing pumps, the drainage pump, the wash water supply pump, and the first to thirteenth solenoid valves based on data received from the pressure sensing means, the first to third radiation dose rate detection means, and the radionuclide analysis device, and operation commands received from the pressure sensing means; and a control panel that is equipped with a display unit for displaying received information, an input unit for inputting operator commands, and an operation status display unit for outputting the system's operation status visually and audibly, and is connected to the control unit to display various information transmitted from the control unit on the display unit, output normal, abnormal, and emergency statuses during system operation to the operation status display unit, and transmit the operator's operation commands to the control unit through the input unit.

Description

Technology Field

[0001] The present invention relates to a drying system for a canister loaded with spent nuclear fuel, and more specifically, to a structure that rapidly dries the interior of a canister, which contains spent nuclear fuel released from a nuclear power plant and is temporarily stored in a temporary storage tank within the nuclear power plant, to meet required conditions, while simultaneously allowing the drying status to be checked in real time; detecting the radiation dose rate for water and air during the execution of the drainage and depressurization drying process; and when a preset radiation dose rate is detected, performing radionuclide analysis on water and air samples to determine whether the spent nuclear fuel cladding is damaged; and when damage to the spent nuclear fuel cladding is confirmed, immediately stopping the depressurization drying process for the corresponding canister and returning it to the temporary storage tank. This allows for the depressurization drying process to be carried out more safely and cost-effectively, significantly improves work productivity through rapid drying, and reliably prevents the long-term disposal of a radioactive waste transport and storage container that has completed drying while containing spent nuclear fuel with damaged cladding. This relates to a drying system for canisters loaded with spent nuclear fuel. Background Technology

[0003] Generally, nuclear reactors are broadly classified into heavy water reactors, which use heavy water (D2O), and light water reactors, which use ordinary water, or light water (H2O), depending on the type of moderator used. Korea possesses both light water and heavy water reactors, and the majority of the reactors in its possession are light water reactors.

[0004] These reactors generate electricity using the heat produced as the nuclear fuel loaded inside burns as an energy source, and the spent nuclear fuel, once combustion is complete, is contained in canisters and stored in the temporary storage facilities of nuclear power plants.

[0005] In particular, spent nuclear fuel released from light water reactors is classified into low burnup spent nuclear fuel and high burnup spent nuclear fuel, and burnup represents the amount of energy produced by the reaction with neutrons from the time the fuel loaded in the core during reactor operation is withdrawn from the reactor. In the case of Korea, low burnup spent nuclear fuel is produced by the combustion of fuel loaded and used in light water reactors before the early 2000s, while high burnup spent nuclear fuel is produced by the combustion of fuel loaded and used in light water reactors after the late 2000s, manufactured with advanced technology such as increased enrichment through technological development.

[0006] That is, in light water reactors, spent fuel with a burnup of 45,000 MWD / MTU or higher is classified as high burnup spent fuel, and spent fuel with a burnup of less than 45,000 MWD / MTU is classified as low burnup spent fuel.

[0007] The storage, processing, and transport of such low-burnup and high-burnup spent nuclear fuel require special care and procedural safety measures. In the operation of a reactor, a hollow Zircaloy tube filled with enriched uranium, known as a fuel assembly, is burned inside the reactor core. It is customary to remove this fuel assembly from the reactor after its energy has been reduced to a predetermined level. During the energy reduction and subsequent removal, this spent nuclear fuel (SNF) remains highly radioactive and generates significant heat, requiring great caution in subsequent packaging, transport, and storage. Specifically, spent nuclear fuel emits extremely dangerous neutrons and gamma rays. It is essential that these neutrons and gamma rays be sealed off at all times after removal from the core.

[0008] When extracting fuel from a nuclear reactor, it is widely known that spent fuel is removed from the reactor and placed underwater, that is, in what is generally known as a spent fuel pool or reservoir. The water in the pool promotes the cooling of the spent fuel and provides adequate radiation shielding. The storage of spent fuel in the pool is for a sufficiently long period during which the heat dissipation and radioactive decay reach sufficiently low levels, thereby enabling the safe transport of the spent fuel. However, due to safety, space, and economic concerns, the use of pools alone is insufficient when spent fuel needs to be stored for a considerable period. Therefore, when long-term storage of spent fuel is required, the standard method in the nuclear industry is to store the spent fuel in a dry state following a short storage period in a spent fuel pool—that is, to store the spent fuel in a dry, inert gas atmosphere inside a structure that provides adequate radiation shielding. One representative structure used to store spent nuclear fuel in a dry state for a long period is a storage cask.

[0009] As a result of the need for spent nuclear fuel for removal from the spent fuel pool and transport to additional storage casks, open canisters are typically submerged in the spent fuel pool before the spent fuel is removed from the reactor core. The spent fuel is then placed directly into the open canisters while submerged. However, even after sealing, the canisters alone cannot provide adequate containment of radiation from the spent fuel. Loaded canisters cannot be removed from or transported from the spent fuel pool without additional radiation shielding. For this reason, devices and methods have been developed to provide additional radiation shielding during the transport of spent nuclear fuel. Additional radiation shielding is typically achieved by placing the canisters inside large cylindrical containers, known as transport casks, while they are submerged in the pool. Similar to storage casks, transfer casks have a cavity of a suitable size to accommodate canisters of spent nuclear fuel inside and are designed to shield the environment from radiation emitted by the spent nuclear fuel inside.

[0010] In a facility that uses a transfer cask to transport canisters containing spent nuclear fuel, an empty canister is first placed into the cavity of the transfer cask. Then, the canister and the transfer cask are submerged in a spent fuel pool. Prior to this, spent nuclear fuel removed from the reactor and placed in a wet storage facility is transferred to the submerged canister (which is inside the transfer cask and filled with water) and loaded into the canister. After the canister loaded with spent nuclear fuel is loaded, a cover is installed, and the cover surrounds the spent nuclear fuel and the water from the pool inside the canister. Then, the canister containing the spent nuclear fuel and the transfer cask are removed from the pool by a crane and landed in an assembly area to prepare canisters containing spent nuclear fuel (SNF) for storage or transport in a dry state. For the purpose of properly preparing canisters containing spent nuclear fuel for dry storage or transport, the United States Nuclear Regulatory Commission (NRC) requires that the spent nuclear fuel and the interior of the canister be properly dried before the canister is sealed and transported to a storage cask. Specifically, NRC regulations require that the vapor pressure (vP) inside the canister be 3 Torr (1 Torr = 1 mmHg) or lower before the canister is filled with non-reactive gas and sealed. Vapor pressure is the pressure of vapor relative to the liquid in equilibrium, where equilibrium is defined as a state in which the number of molecules changing from the liquid state to the gaseous state is equal to the number of molecules changing from the gaseous state to the liquid state. The requirement for a vapor pressure (vP) of 3 Torr or lower ensures an adequate dry space inside the canister, which is desirable for the long-term storage or transport of spent nuclear fuel.

[0011] Currently, nuclear facilities satisfy the NRC's requirement for a vapor pressure (vP) of 3 Torr or lower by implementing a vacuum drying process. When implementing this process, the bulk water inside the canister is first discharged from the canister. Once the liquid bulk water is discharged, a vacuum system is connected to the canister and operated to generate a pressure lower than atmospheric pressure inside the canister. While the sub-atmosphere pressure inside the canister promotes the evaporation of the remaining liquid water, the vacuum assists in removing water vapor. The vapor pressure (vP) inside the canister is experimentally verified through a vacuum-and-hold procedure. If necessary, this vacuum-and-hold procedure is repeated until the pressure rise during a specified test time (30 minutes) is limited to 3 Torr. Once the vacuum drying passes the acceptance test, the canister is filled with a non-reactive gas and sealed. The transfer cask (equipped with a container for transporting and storing radioactive waste) is then transported to the upper position of the storage cask, and the canister containing the spent nuclear fuel is transported to a storage device for long-term storage.

[0012] Current methods to meet the NRC's vapor pressure (vP) requirements of 3 Torr or lower are time-consuming, manual, and prone to errors in the lines and valve leaks. Whenever physical access to the canister is required for vacuum monitoring and drying tests, there is a risk of high radiation exposure to workers. Furthermore, generating pressure lower than atmospheric pressure inside the canister requires expensive vacuum equipment and can lead to complex equipment issues.

[0013] A patent developed to solve these conventional problems is "Method and apparatus for drying high-level waste based on dew point temperature measurement" (hereinafter referred to as the "prior art"), which was filed by Holtech International with the Korean Intellectual Property Office on June 6, 2006, and registered as a patent on December 7, 2010.

[0014] Looking briefly at the configuration of the prior art, it is "a method for drying a cavity loaded with high-level waste (HLW), comprising: (a) a step of allowing a non-reactive gas to flow through said cavity; (b) a step of repeatedly measuring the dew point temperature of said non-reactive gas exiting said cavity; and (c) a step of stopping the flow of the non-reactive gas and sealing the cavity when, for a predetermined time, the dew point temperature of said non-reactive gas exiting said cavity is equal to or lower than a predetermined dew point temperature." and "a system for drying a cavity loaded with high-level waste (HLW), comprising a canister (a container for transporting and storing radioactive waste) constituting said cavity having an inlet and an outlet; a non-reactive gas source; a flow means for allowing the non-reactive gas from said non-reactive gas source to flow through said cavity; and a dew point temperature for repeatedly measuring the dew point temperature of said non-reactive gas exiting said cavity." A system comprising a measuring means and a controller operably connected to the dew point temperature measuring means, wherein the dew point temperature measuring means is suitable for generating a signal indicating the dew point temperature of the non-reactive gas measured and transmitting it to the controller, wherein the controller is suitable for interpreting the signal, and when the controller determines that the signal indicates that the measured dew point temperature is equal to or lower than a predetermined dew point temperature for a predetermined time, the controller is more suitable for at least one of (i) stopping the flow of the non-reactive gas through the cavity, and (ii) operating a means indicating that the cavity is in a dry state.

[0015] However, although this prior art invention is configured to dry the internal space of a radioactive waste transport and storage container containing spent nuclear fuel using a gas circulation drying method that circulates non-reactive gas, implementing this conventional gas circulation drying method requires a gas circulation drying system with a complex structure and a very large volume. Furthermore, due to the large consumption of expensive non-reactive gas, the installation and maintenance costs of the system are very high, and the drying process takes a long time, resulting in a significant decrease in work productivity. In addition, there are problems such as inefficient consumption of excessive costs and time because drying is performed according to the same process for both high-burnup and low-burnup spent nuclear fuel without considering their respective characteristics.

[0017] The applicant has made various attempts to overcome the aforementioned conventional problems, and as a result, has developed a "method for drying a radioactive waste transport and storage container," which was filed with the Korean Intellectual Property Office on May 27, 2024, and assigned application number "Patent Application No. 10-2024-0068730," and was granted "Registered Patent No. 10-2794827" (hereinafter referred to as the "prior registered invention") on April 8, 2025. The composition thereof comprises an internal temperature measurement initiation step of a radioactive waste transport and storage container in which the temperature inside the radioactive waste transport and storage container containing spent nuclear fuel is measured, a water drainage step of a radioactive waste transport and storage container in which water filled inside the radioactive waste transport and storage container containing spent nuclear fuel is drained to the outside through a drain port, and if the water drainage step of a radioactive waste transport and storage container is completed, A preliminary drying step of a radioactive waste transport and storage container in which air inside the radioactive waste transport and storage container is exhausted through the drain or exhaust port of the radioactive waste transport and storage container until a preset vacuum pressure value is reached; a main drying step of a radioactive waste transport and storage container in which, if the preliminary drying step of the radioactive waste transport and storage container is completed, air inside the radioactive waste transport and storage container is exhausted stepwise through the drain or exhaust port of the radioactive waste transport and storage container until the vacuum pressure inside the radioactive waste transport and storage container reaches a preset final vacuum pressure value to vacuum dry the interior of the radioactive waste transport and storage container; a non-reactive gas injection step into the radioactive waste transport and storage container in which a non-reactive gas is injected into the radioactive waste transport and storage container if the main drying step of the radioactive waste transport and storage container is completed; and, if the non-reactive gas injection step into the radioactive waste transport and storage container is completed, for a preset time,A final vacuum pressure change verification step within a preset time to verify whether the vacuum pressure inside the radioactive waste transport and storage container is maintained below the final vacuum pressure value; a sealing step of the radioactive waste transport and storage container to seal the radioactive waste transport and storage container and terminate vacuum drying of the radioactive waste transport and storage container if, in the final vacuum pressure change verification step within the preset time, the vacuum pressure inside the radioactive waste transport and storage container is maintained below the final vacuum pressure value for the preset time; a re-drying step of the radioactive waste transport and storage container to recover the non-reactive gas filled in the canister and return to the preliminary drying step of the radioactive waste transport and storage container to re-perform drying of the radioactive waste transport and storage container if, in the final vacuum pressure change verification step within the preset time, the vacuum pressure inside the canister rises above the final vacuum pressure value for the preset time; and radioactive waste while the main drying step of the radioactive waste transport and storage container is executed A step for verifying the internal temperature of a radioactive waste transport and storage container to check whether the internal temperature of the transport and storage container has reached a preset target temperature; and, in the step for verifying the internal temperature of the radioactive waste transport and storage container, if it is confirmed that the internal temperature of the radioactive waste transport and storage container has reached a preset target temperature, a step for counting the elapsed time after reaching a preset temperature to count the time from when the internal temperature reached the preset target temperature; and checking whether the counted time until the main drying step of the radioactive waste transport and storage container is being executed or until the main drying step of the radioactive waste transport and storage container is completed is greater than or equal to a preset limit time, and if the counted time is less than the preset limit time, if the main drying step of the radioactive waste transport and storage container is being executed, continuing to execute the main drying step of the radioactive waste transport and storage container.A method for drying a radioactive waste transport and storage container containing spent nuclear fuel comprises: a counting time verification step for executing a non-reactive gas injection step within the radioactive waste transport and storage container when the main drying step of the radioactive waste transport and storage container is completed; and, in the counting time verification step, if the counted time is longer than a preset time, an internal cooling step of the radioactive waste transport and storage container for immediately terminating the main drying step of the radioactive waste transport and storage container and simultaneously filling the radioactive waste transport and storage container with cooling water to cool the radioactive waste transport and storage container to a preset target temperature, wherein the main drying step of the radioactive waste transport and storage container comprises a first depressurization step for exhausting air inside the radioactive waste transport and storage container through a drain or exhaust port of the radioactive waste transport and storage container containing high burnup spent nuclear fuel until a preset target pressure value is reached; The above-mentioned first depressurization step is completed, comprising a first depressurization state waiting step in which the radioactive waste transport and storage container and the vacuum pump are isolated and waited for a preset waiting time; a final depressurization step in which the air inside the radioactive waste transport and storage container is exhausted through the drain or exhaust port of the radioactive waste transport and storage container until a preset target pressure value is reached, in which the above-mentioned first depressurization state waiting step is completed, in which the radioactive waste transport and storage container and the vacuum pump are isolated and waited for a preset waiting time; and a pressure change verification step in which, in which the above-mentioned final depressurization state waiting step is completed, the pressure inside the radioactive waste transport and storage container is checked to see if it has risen, and if it has risen, the process returns to the above-mentioned final depressurization step.

[0018] While the applicant's prior registered invention, having the configuration described above, has the advantage of being able to safely and inexpensively perform a depressurized drying process on a radioactive waste transport and storage container containing radioactive waste, specifically spent nuclear fuel (SFN), by using a depressurized device in a depressurized manner, and significantly improving work productivity associated with such drying, it has the problem that the spent nuclear fuel cladding may be damaged due to the differential pressure between the spent nuclear fuel contained within the container and the internal space of the container during the depressurized drying process, and that it is not possible to verify whether such damage to the cladding has occurred during or after the depressurized drying process is completed.

[0019] In order to overcome the problems of the applicant’s prior invention, the applicant made various efforts, and as a result, developed a ‘method for drying a canister loaded with spent nuclear fuel’ capable of detecting whether the spent nuclear fuel cladding is damaged during the drying process, and filed a patent application with the Korea Intellectual Property Office on July 13, 2026, and was assigned patent application number ‘Patent Application No. 10-2026-0128092’ (hereinafter referred to as the ‘prior invention’). Attached drawing Fig. 1 is a diagram illustrating the configuration of the prior invention developed by the applicant.

[0020] The prior filed invention developed by the applicant comprises: a drainage step (S100) of a canister in which the internal pressure of the canister is measured, and water filled inside the canister loaded with spent nuclear fuel is drained to the outside through a drain port; and, if the water drainage step (S100) inside the canister is completed, a preliminary depressurization drying step (S200) of a canister in which the drain port of the canister is kept closed until the pressure inside the canister reaches a preliminary drying pressure value of 100 Torr, and air inside the canister (air containing non-reactive gas and moisture) is exhausted through an exhaust port to primarily depressurize and dry the interior of the canister. After the preliminary vacuum drying step (S200) of the canister is completed, a vacuum vaporization promotion step (S300) inside the canister in which the exhaust port of the canister is kept closed for a preset time so that moisture remaining inside the canister due to rapid vacuum reduction can be filled into the inner space of the canister to promote vacuum vaporization without freezing; and if the vacuum vaporization promotion step (S300) inside the canister is completed, a main vacuum drying step (S400) of the canister in which the air inside the canister is exhausted through the exhaust port of the canister until the pressure inside the canister reaches a preset main drying pressure value to secondarily vacuum dry the interior of the canister; If the main vacuum drying step (S400) of the canister is completed, an internal pressure measurement step (S500) of the canister that keeps the exhaust port and drain port of the canister closed and measures the internal pressure of the canister for 30 minutes; and a drying completion confirmation step (S600) of the canister that checks whether the internal pressure of the canister in the internal pressure measurement step (S500) is less than the reference vacuum drying pressure of 3 Torr, and if the internal pressure inside the canister is greater than or equal to the reference vacuum drying pressure, returns to the preliminary vacuum drying step (S200) of the canister;In the step of confirming the completion of drying of the canister (S600), if the pressure inside the canister is less than the reference drying pressure of 3 Torr, a sealing step of the canister (S700) in which a non-reactive gas is injected into the canister so that the cladding of the spent nuclear fuel stored inside does not react with air and be damaged, and the canister is tightly sealed so that leakage does not occur during the transport and storage of the canister; and a radiation dose rate detection step (S800) in which a radiation dose rate detection means is operated to detect the radiation dose rate of the water drained through the canister's drain port and the exhausted air in real time while any one of the steps of the canister draining step (S100), the canister preliminary depressurization drying step (S200), and the canister main depressurization drying step (S400), or both steps, are being executed; A radiation dose rate verification step (S900) that checks whether the radiation dose rate for water and air detected in the radiation dose rate detection step (S800) is greater than or equal to a preset radiation dose rate, and if the detected radiation dose rate is less than the preset radiation dose rate, returns to the radiation dose rate detection step; a sample collection and radionuclide analysis step (S1000) that, in the radiation dose rate verification step (S900), if the detected radiation dose rate is greater than or equal to a preset radiation dose rate, collects a water sample or an air sample and performs radionuclide analysis on the collected water sample or air sample using a radionuclide analyzer; and a spent nuclear fuel cladding damage verification step (S1100) that checks whether an evidential radionuclide of spent nuclear fuel cladding damage has been detected in the sample collection and radionuclide analysis step (S1000), and if an evidential radionuclide has not been detected, returns to the radiation dose rate detection step;In the above-mentioned step for checking whether the spent nuclear fuel cladding is damaged (S1100), if damage to the spent nuclear fuel cladding is confirmed, the process comprises a step for draining the canister with confirmed damage to the spent nuclear fuel cladding (S100), a step for pre-drying the canister (S200), and a step for main drying the canister (S400) currently in progress, and a spent nuclear fuel cladding damage determination canister return step (S1200) in which the canister with confirmed damage to the spent nuclear fuel cladding is returned to a temporary storage pool.

[0021] The applicant's prior invention having such a configuration contains spent nuclear fuel released from a nuclear power plant and rapidly dries the interior of a canister temporarily stored in a temporary storage pool within the nuclear power plant to meet required conditions, while simultaneously allowing the drying status to be checked in real time. Furthermore, it detects the radiation dose rate for water and air during the execution of the drainage and depressurization drying process, and when a preset radiation dose rate is detected, performs radionuclide analysis on water and air samples to determine whether the spent nuclear fuel cladding is damaged. When damage to the spent nuclear fuel cladding is confirmed, it immediately stops the depressurization drying process for the corresponding canister and returns it to the temporary storage pool. This allows for the depressurization drying process to be carried out more safely and cost-effectively, significantly improves work productivity due to rapid drying, and reliably prevents the long-term disposal of a canister that has completed drying while containing spent nuclear fuel with damaged cladding. The applicant [claims] that the applicant's 'canister loaded with spent nuclear fuel' possesses these advantages There was an urgent need to develop a hardware system capable of safely and accurately implementing the 'drying method'. Prior art literature

[0023] Republic of Korea Registered Patent No. 10-2794827 (April 8, 2025) The problem to be solved

[0024] The present invention was devised in response to the applicant's needs as described above, and its purpose is to rapidly dry the interior of a canister containing spent nuclear fuel released from a nuclear power plant and temporarily stored in a temporary storage pool within the nuclear power plant to meet required standards, while simultaneously enabling real-time verification of the drying status; detecting radiation dose rates for water and air during the execution of the drainage and depressurization drying process; and when a preset radiation dose rate is detected, performing radionuclide analysis on water and air samples to determine whether the spent nuclear fuel cladding is damaged; and, if damage to the spent nuclear fuel cladding is confirmed, immediately stopping the depressurization drying process for the corresponding canister and returning it to the temporary storage pool. This allows for the depressurization drying process to be carried out more safely and cost-effectively, significantly improves work productivity through rapid drying, and reliably prevents the long-term disposal of a canister that has completed drying while containing spent nuclear fuel with damaged cladding. The purpose is to provide a drying system for a canister loaded with spent nuclear fuel that can safely and accurately carry out the drying method. means of solving the problem

[0026] The objective of the present invention is to provide a canister drainage step of measuring the internal pressure of a canister while simultaneously draining water filled inside a canister loaded with spent nuclear fuel to the outside through a drain port; a canister preliminary depressurization drying step of a canister in which, if the water drainage step inside the canister is completed, the canister drain port is kept closed until the pressure inside the canister reaches a preliminary drying pressure value of 100 Torr, and the air inside the canister is exhausted through an exhaust port to primarily depressurize the interior of the canister; and a depressurization vaporization promotion step inside the canister in which, after the preliminary depressurization drying step is completed, the canister exhaust port is kept closed for a preset time so that moisture remaining inside the canister due to rapid depressurization can be filled into the inner space of the canister to promote depressurization vaporization without freezing. If the depressurization vaporization promotion step inside the canister is completed, a main depressurization drying step of the canister in which the air inside the canister is exhausted through the canister's exhaust port until the pressure inside the canister reaches a preset main drying pressure value, thereby secondarily depressurizing the interior of the canister; if the main depressurization drying step of the canister is completed, an internal pressure measurement step of the canister in which the exhaust port and drain port of the canister are kept closed and the internal pressure of the canister is measured for 30 minutes; and a drying completion confirmation step of the canister in which, during the internal pressure measurement step of the canister, it is checked whether the internal pressure of the canister is less than the reference depressurization drying pressure of 3 Torr, and if the internal pressure inside the canister is greater than or equal to the reference depressurization drying pressure, the process returns to the preliminary depressurization drying step of the canister;In the step of confirming the completion of drying of the canister, if the pressure inside the canister is less than the reference drying pressure of 3 Torr, a sealing step of the canister in which a non-reactive gas is injected into the canister to prevent damage from the cladding of the spent nuclear fuel stored inside reacting with air, and the canister is tightly sealed to prevent leakage during transport and storage of the canister; a radiation dose rate detection step of detecting the radiation dose rate of water drained through the canister's drain port and exhausted air in real time by operating a radiation dose rate detection means while any one of the steps of the canister draining step, the canister preliminary depressurization drying step, and the canister main depressurization drying step, or both steps, are being executed; and a radiation dose rate verification step of confirming whether the radiation dose rate of water and air detected in the radiation dose rate detection step is greater than or equal to a preset radiation dose rate, and if the detected radiation dose rate is less than the preset radiation dose rate, returning to the radiation dose rate detection step. In the radiation dose rate verification step, if the detected radiation dose rate is greater than or equal to a preset radiation dose rate, a sample collection and radionuclide analysis step of collecting a water sample or an air sample and performing radionuclide analysis of the collected water sample or air sample using a radionuclide analyzer; and a spent fuel cladding damage verification step of checking whether an evidential radionuclide of spent fuel cladding damage has been detected in the sample collection and radionuclide analysis step, and returning to the radiation dose rate detection step if the evidential radionuclide has not been detected;A drying system for a canister loaded with spent nuclear fuel, comprising a drying method for a canister loaded with spent nuclear fuel, wherein, in the step of confirming whether the spent nuclear fuel cladding is damaged, if damage to the spent nuclear fuel cladding is confirmed, the execution of the step currently being executed among the draining step of the canister, the preliminary drying step of the canister, and the main drying step of the canister, is stopped, and the canister with confirmed damage to the spent nuclear fuel cladding is returned to a temporary storage pool, wherein the drying system has first to fifth connectors and a pressure gauge mounting hole, and as a distribution means for controlling the air flow path, an air distribution device in which the first connector is detachably connected to the exhaust port of the canister so as to be connected in communication with the inner hollow of the canister; A first to fifth solenoid valve, each mounted on a first to fifth connector of the air distribution device and opening and closing the first to fifth connectors; a pressure sensing means mounted on a pressure gauge mounting hole of the air distribution device to detect the internal pressure of the canister and transmit the pressure sensing value; a non-reactive gas supply tank having an exhaust port in which non-reactive gas is stored, connected to the second connector of the air distribution device via a gas supply pipe to communicate with the second connector, and supplying and stopping the supply of non-reactive gas into the canister through the air distribution device according to the opening and closing operation of the second solenoid valve so that non-reactive gas is filled into the empty space where water in the canister is drained; and a radionuclide analysis device having a sample analysis chamber filled with a collected sample and a radionuclide analysis unit that analyzes radionuclides among the sample in the sample analysis chamber, and analyzing radionuclides of the collected air and water samples among the air and water discharged from the exhaust port and drain port of the canister; A primary pressure reducing exhaust pipe connected to communicate with the third connector of the air distribution device and exhausting air inside the canister to the exhaust system; and a sixth solenoid valve mounted on the exhaust system-side end of the primary pressure reducing exhaust pipe and opening and closing the exhaust system-side end of the primary pressure reducing exhaust pipe;A primary pressure reducing pump mounted on the primary pressure reducing exhaust pipe between the third and sixth solenoid valves and pumping air inside the canister to be exhausted into the exhaust system through the primary pressure reducing exhaust pipe; a first radiation dose rate detection means mounted on the primary pressure reducing exhaust pipe between the third solenoid valve and the primary pressure reducing pump and detecting the radiation dose rate of the air exhausted into the exhaust system along the primary pressure reducing exhaust pipe in real time and transmitting the detected value; a first air sample collection tube branched to communicate with the primary pressure reducing exhaust pipe between the sixth solenoid valve and the primary pressure reducing pump, connected to communicate with the inlet of the sample analysis chamber of the radionuclide analyzer, and supplying an air sample collected from the primary pressure reducing exhaust pipe into the sample analysis chamber of the radionuclide analyzer; and a seventh solenoid valve mounted on the first air sample collection tube and opening and closing the first air sample collection tube; A secondary pressure reducing exhaust pipe connected to communicate with the fourth connector of the air distributor device and exhausting air inside the canister into the exhaust system; an eighth solenoid valve mounted on the exhaust system-side end of the secondary pressure reducing exhaust pipe and opening and closing the exhaust system-side end of the secondary pressure reducing exhaust pipe; a secondary pressure reducing pump mounted on the secondary pressure reducing exhaust pipe between the fourth and eighth solenoid valves and pumping air inside the canister to be exhausted into the exhaust system through the secondary pressure reducing exhaust pipe; and a second radiation dose rate detection means mounted on the secondary pressure reducing exhaust pipe between the fourth solenoid valve and the secondary pressure reducing pump, detecting the radiation dose rate of the air exhausted into the exhaust system along the secondary pressure reducing exhaust pipe in real time and transmitting the detected value; A second air sample collection tube that branches off to communicate with the secondary pressure exhaust pipe between the eighth solenoid valve and the secondary pressure pump, is connected to communicate with the inlet of the sample analysis chamber of the radionuclide analyzer, and supplies an air sample collected from the secondary pressure exhaust pipe into the sample analysis chamber of the radionuclide analyzer;A ninth solenoid valve mounted on the second air sample collection tube and opening and closing the second air sample collection tube; a drain pipe detachably connected to the drain port of a canister and draining water filled in the canister into a drainage system; tenth and eleventh solenoid valves each mounted on both ends of the drain pipe and opening and closing both ends of the drain pipe; a drain pump mounted on the drain pipe between the tenth and eleventh solenoid valves and pumping and draining water filled in the canister; a third radiation dose rate detection means mounted on the drain pipe between the tenth solenoid valve and the drain pump, detecting the radiation dose rate of the water drained along the drain pipe in real time and transmitting the detected value; and a water sample collection tube branched out to communicate with the drain pipe between the eleventh solenoid valve and the drain pump, connected to communicate with the inlet of the sample analysis chamber of the radionuclide analyzer, and supplying a water sample collected from the drain pipe into the sample analysis chamber of the radionuclide analyzer. A 12th solenoid valve mounted on the water sample collection tube and opening and closing the water sample collection tube; a wash water supply tank having a drain port in which wash water is stored, which supplies wash water into the primary and secondary pressure reduction exhaust pipes and the drain port to perform washing; a first wash water supply pipe branched to communicate from the drain port between the 10th solenoid valve and the third radiation dose rate detection means, and connected to communicate with the drain port of the wash water supply tank to supply wash water into the drain port; a 13th solenoid valve mounted on the first wash water supply pipe and opening and closing the first wash water supply pipe; and a wash water supply pump mounted on the first wash water supply pipe between the wash water supply tank and the 13th solenoid valve and pumping wash water within the wash water supply tank; A second wash water supply pipe that branches off from the first wash water supply pipe between the wash water supply pump and the 13th solenoid valve and is connected to communicate with the 5th connector of the air distribution device to supply wash water into the first and second pressure reducing exhaust pipes;This can be achieved by a drying system for a canister loaded with spent nuclear fuel, characterized by comprising: a control unit that is respectively connected to the pressure sensing means, first to third radiation dose rate detection means, radionuclide analysis device, first and second depressurization pumps, drainage pump, wash water supply pump, and first to thirteenth solenoid valves, and controls the operation of the first and second depressurization pumps, drainage pump, wash water supply pump, and first to thirteenth solenoid valves based on data received from the pressure sensing means, first to third radiation dose rate detection means, and radionuclide analysis device and received operation commands; and a control panel that is connected to the control unit, displays various information transmitted from the control unit on the display unit, outputs normal, abnormal, and emergency statuses during system operation to the operation status display unit, and transmits the operator's operation commands to the control unit through the input unit.

[0028] The objective of the present invention is to provide a canister drainage step of measuring the internal pressure of a canister while simultaneously draining water filled inside a canister loaded with spent nuclear fuel to the outside through a drain port; a canister preliminary depressurization drying step of a canister in which, if the water drainage step inside the canister is completed, the canister drain port is kept closed until the pressure inside the canister reaches a preliminary drying pressure value of 100 Torr, and the air inside the canister is exhausted through an exhaust port to primarily depressurize the interior of the canister; and a depressurization vaporization promotion step inside the canister in which, after the preliminary depressurization drying step is completed, the canister exhaust port is kept closed for a preset time so that moisture remaining inside the canister due to rapid depressurization can be filled into the inner space of the canister to promote depressurization vaporization without freezing. If the depressurization vaporization promotion step inside the canister is completed, a main depressurization drying step of the canister in which the air inside the canister is exhausted through the canister's exhaust port until the pressure inside the canister reaches a preset main drying pressure value, thereby secondarily depressurizing the interior of the canister; if the main depressurization drying step of the canister is completed, an internal pressure measurement step of the canister in which the exhaust port and drain port of the canister are kept closed and the internal pressure of the canister is measured for 30 minutes; and a drying completion confirmation step of the canister in which, during the internal pressure measurement step of the canister, it is checked whether the internal pressure of the canister is less than the reference depressurization drying pressure of 3 Torr, and if the internal pressure inside the canister is greater than or equal to the reference depressurization drying pressure, the process returns to the preliminary depressurization drying step of the canister;In the step of confirming the completion of drying of the canister, if the pressure inside the canister is less than the reference drying pressure of 3 Torr, a sealing step of the canister in which a non-reactive gas is injected into the canister to prevent damage from the cladding of the spent nuclear fuel stored inside reacting with air, and the canister is tightly sealed to prevent leakage during transport and storage of the canister; a radiation dose rate detection step of detecting the radiation dose rate of water drained through the canister's drain port and exhausted air in real time by operating a radiation dose rate detection means while any one of the steps of the canister draining step, the canister preliminary depressurization drying step, and the canister main depressurization drying step, or both steps, are being executed; and a radiation dose rate verification step of confirming whether the radiation dose rate of water and air detected in the radiation dose rate detection step is greater than or equal to a preset radiation dose rate, and if the detected radiation dose rate is less than the preset radiation dose rate, returning to the radiation dose rate detection step. In the radiation dose rate verification step, if the detected radiation dose rate is greater than or equal to a preset radiation dose rate, a sample collection and radionuclide analysis step of collecting a water sample or an air sample and performing radionuclide analysis of the collected water sample or air sample using a radionuclide analyzer; and a spent fuel cladding damage verification step of checking whether an evidential radionuclide of spent fuel cladding damage has been detected in the sample collection and radionuclide analysis step, and returning to the radiation dose rate detection step if the evidential radionuclide has not been detected;A drying system for a canister loaded with spent nuclear fuel for implementing a drying method for a canister loaded with spent nuclear fuel, comprising, if damage to the spent nuclear fuel cladding is confirmed in the step of confirming damage to the spent nuclear fuel cladding, stopping the execution of the step currently being executed among the draining step of the canister, the preliminary drying step of the canister, and the main drying step of the canister, and returning the canister with confirmed damage to the spent nuclear fuel cladding to a temporary storage pool, wherein the drying system has first to fifth connectors and a pressure gauge mounting hole, and as a distribution means for controlling the air flow path, an air distribution device in which the first connector is detachably connected to the drain port of the canister so as to be connected in communication with the inner hollow of the canister; A first to fifth solenoid valve, each mounted on the first to fifth connectors of the air distribution device and opening and closing the first to fifth connectors; a pressure sensing means mounted on the pressure gauge mounting hole of the air distribution device to detect the internal pressure of the canister and transmit the pressure sensing value; a non-reactive gas supply tank, which is a tank having an exhaust port in which non-reactive gas is stored, connected to the exhaust port of the canister through a gas supply pipe to communicate with the canister, and supplies and stops supplying non-reactive gas into the canister through the air distribution device according to the opening and closing operation of the second solenoid valve so that non-reactive gas is filled into the empty space where water in the canister has been drained; and a 13th solenoid valve, which is mounted on the gas supply pipe and opens and closes the gas supply pipe; A sample analysis chamber filled with collected samples and a radionuclide analysis unit for analyzing radionuclides among the samples within the sample analysis chamber, and a radionuclide analysis device for analyzing radionuclides in collected air and water samples discharged from the drain of a canister; a drain pipe connected to communicate with the third connector of the air distribution device and draining water within the canister into a drainage system; and an eleventh solenoid valve mounted on the drain pipe and opening and closing the drain.A drainage pump mounted on the drain pipe between the first solenoid valve and the third solenoid valve of the third connector of the air distribution device, and pumping water filled in a canister to be discharged through a drain and drained into a drainage system along the drain pipe; a third radiation dose rate detection means mounted on the drain pipe between the drainage pump and the third solenoid valve, detecting the radioactivity rate of the water drained along the drain pipe in real time and transmitting the detected value; a water sample collection tube branched out to communicate with the drain pipe between the drainage pump and the first solenoid valve, connected to communicate with the inlet of the sample analysis chamber of the radionuclide analysis device, and supplying a water sample collected from the drain pipe into the sample analysis chamber of the radionuclide analysis device; a third solenoid valve mounted on the water sample collection tube and opening and closing the water sample collection tube; and a primary depressurization exhaust pipe connected to communicate with the fourth connector of the air distribution device and exhausting air inside the canister into an exhaust system; A sixth solenoid valve mounted on the primary pressure reducing exhaust pipe and opening and closing the primary pressure reducing exhaust pipe; a primary pressure reducing pump mounted on the primary pressure reducing exhaust pipe between the sixth solenoid valve and the fourth solenoid valve of the fourth connector of the air distribution device and pumping air inside the canister to be exhausted to the exhaust system through the primary pressure reducing exhaust pipe; and a first radiation dose rate detection means mounted on the primary pressure reducing exhaust pipe between the fourth solenoid valve of the fourth connector of the air distribution device and the primary pressure reducing pump, detecting the radiation dose rate of the air exhausted to the exhaust system along the primary pressure reducing exhaust pipe in real time and transmitting the detected value; A first air sample collection tube that branches off to communicate with the primary pressure exhaust pipe between the primary pressure pump and the sixth solenoid valve, is connected to communicate with the inlet of the sample analysis chamber of the radionuclide analyzer, and supplies an air sample collected from the primary pressure exhaust pipe into the sample analysis chamber of the radionuclide analyzer; and a seventh solenoid valve mounted on the first air sample collection tube and opening and closing the first air sample collection tube;A secondary pressure reducing exhaust pipe connected to communicate with the fifth connector of the air distribution device and exhausting air inside a canister into an exhaust system; an eighth solenoid valve mounted on the secondary pressure reducing exhaust pipe and opening and closing the secondary pressure reducing exhaust pipe; a secondary pressure reducing pump mounted on the secondary pressure reducing exhaust pipe between the eighth solenoid valve and the fifth solenoid valve of the fifth connector of the air distribution device and pumping air inside a canister to be exhausted into the exhaust system through the secondary pressure reducing exhaust pipe; and a second radiation dose rate detection means mounted on the secondary pressure reducing exhaust pipe between the fifth solenoid valve of the fifth connector of the air distribution device and the secondary pressure reducing pump, which detects the radiation dose rate of the air exhausted into the exhaust system along the secondary pressure reducing exhaust pipe in real time and transmits the detected value; A second air sample collection tube that branches off to communicate with the secondary pressure exhaust pipe between the second pressure reducing pump and the eighth solenoid valve, is connected to communicate with the inlet of the sample analysis chamber of the radionuclide analyzer, and supplies an air sample collected from the secondary pressure exhaust pipe into the sample analysis chamber of the radionuclide analyzer; a ninth solenoid valve mounted on the second air sample collection tube and opening and closing the second air sample collection tube; a wash water supply tank having a drain port in which wash water is stored, is connected to communicate with the second connector of the air distribution device and the wash water supply pipe, and supplies wash water into the drain pipe and the primary and secondary pressure exhaust pipes by the opening and closing operation of the second solenoid valve to perform washing; and a wash water supply pump mounted on the wash water supply pipe between the second solenoid valve and the wash water supply tank and pumps the wash water within the wash water supply tank;A control unit that controls the operation of the primary and secondary pressure reducing pumps, drainage pumps, wash water supply pumps, first to ninth solenoid valves, eleventh to thirteenth solenoid valves, and the first and second pressure reducing pumps, drainage pumps, wash water supply pumps, eleventh to thirteenth solenoid valves, and the operation of the first and second pressure reducing pumps, drainage pumps, wash water supply pumps, first to ninth solenoid valves, and eleventh to eleventh solenoid valves, respectively, based on data received from the pressure sensing means, first to third radiation dose rate detection means, and the solenoid analysis device, and operation commands received from the pressure sensing means, first to third radiation dose rate detection means, and the solenoid analysis device; This can be achieved by a drying system for a canister loaded with spent nuclear fuel, characterized by comprising a display unit for displaying received information, an input unit for inputting operator commands, and an operation status display unit for outputting the system's operation status visually and audibly, and a control panel connected to the control unit that displays various information transmitted from the control unit on the display unit, outputs normal, abnormal, and emergency statuses during system operation to the operation status display unit, and transmits the operator's operation commands through the input unit to the control unit.

[0030] In addition, the objective of the present invention is a drainage step of a canister in which the internal pressure of the canister is measured, and water filled inside the canister loaded with spent nuclear fuel is drained to the outside through a drain port; a preliminary depressurization drying step of a canister in which, if the water drainage step inside the canister is completed, the drain port of the canister is kept closed until the pressure inside the canister reaches a preliminary drying pressure value of 100 Torr, and the air inside the canister is exhausted through an exhaust port to primarily depressurize the interior of the canister; and a depressurization vaporization promotion step inside the canister in which, after the preliminary depressurization drying step of the canister is completed, the exhaust port of the canister is kept closed for a preset time so that moisture remaining inside the canister due to rapid depressurization can be filled into the inner space of the canister to promote depressurization vaporization without freezing. If the depressurization vaporization promotion step inside the canister is completed, a main depressurization drying step of the canister in which the air inside the canister is exhausted through the canister's exhaust port until the pressure inside the canister reaches a preset main drying pressure value, thereby secondarily depressurizing the interior of the canister; if the main depressurization drying step of the canister is completed, an internal pressure measurement step of the canister in which the exhaust port and drain port of the canister are kept closed and the internal pressure of the canister is measured for 30 minutes; and a drying completion confirmation step of the canister in which, during the internal pressure measurement step of the canister, it is checked whether the internal pressure of the canister is less than the reference depressurization drying pressure of 3 Torr, and if the internal pressure inside the canister is greater than or equal to the reference depressurization drying pressure, the process returns to the preliminary depressurization drying step of the canister;In the step of confirming the completion of drying of the canister, if the pressure inside the canister is less than the reference drying pressure of 3 Torr, a sealing step of the canister in which a non-reactive gas is injected into the canister to prevent damage from the cladding of the spent nuclear fuel stored inside reacting with air, and the canister is tightly sealed to prevent leakage during transport and storage of the canister; a radiation dose rate detection step of detecting the radiation dose rate of water drained through the canister's drain port and exhausted air in real time by operating a radiation dose rate detection means while any one of the steps of the canister draining step, the canister preliminary depressurization drying step, and the canister main depressurization drying step, or both steps, are being executed; and a radiation dose rate verification step of confirming whether the radiation dose rate of water and air detected in the radiation dose rate detection step is greater than or equal to a preset radiation dose rate, and if the detected radiation dose rate is less than the preset radiation dose rate, returning to the radiation dose rate detection step. In the radiation dose rate verification step, if the detected radiation dose rate is greater than or equal to a preset radiation dose rate, a sample collection and radionuclide analysis step of collecting a water sample or an air sample and performing radionuclide analysis of the collected water sample or air sample using a radionuclide analyzer; and a spent fuel cladding damage verification step of checking whether an evidential radionuclide of spent fuel cladding damage has been detected in the sample collection and radionuclide analysis step, and returning to the radiation dose rate detection step if the evidential radionuclide has not been detected;A drying system for a canister loaded with spent nuclear fuel, comprising a drying method for a canister loaded with spent nuclear fuel, wherein, in the step of confirming damage to the spent nuclear fuel cladding, if damage to the spent nuclear fuel cladding is confirmed, the execution of the step currently being executed among the draining step of the canister, the preliminary drying step of the canister, and the main drying step of the canister, is stopped, and the canister with confirmed damage to the spent nuclear fuel cladding is returned to a temporary storage pool, wherein the drying system is a tank having an exhaust port in which non-reactive gas is stored, a non-reactive gas supply tank connected to the exhaust port of the canister through a gas supply pipe to communicate with the exhaust port of the canister, and supplies non-reactive gas into the canister so that the non-reactive gas is filled into the empty space where the water inside the canister is drained; A pressure sensing means mounted on the gas supply pipe, detecting the internal pressure of the canister and transmitting the detected pressure value; a 13th solenoid valve mounted on the gas supply pipe between the pressure sensing means and the non-reactive gas supply tank and opening and closing the gas supply pipe; a drain pipe detachably connected to the drain port of the canister and draining water filled in the canister into a drainage system; 10th and 11th solenoid valves each mounted on both ends of the drain pipe and opening and closing both ends of the drain pipe respectively; a drain pump mounted on the drain pipe between the 10th and 11th solenoid valves and pumping and draining water filled in the canister; and a washing water supply tank having a drain port in which washing water is stored, which supplies washing water into the flow path of water and air discharged through the drain port of the canister to wash. A washing water supply pipe that branches off from the drain pipe between the 10th and 11th solenoid valves and is connected to the drain of the washing water supply tank to supply washing water into the drain pipe; and a second solenoid valve mounted on the washing water supply pipe and opening and closing the washing water supply pipe;A washing water supply pump mounted on a washing water supply pipe between the second solenoid valve and the drain of the washing water supply tank, and pumping washing water within the washing water supply tank so that washing water is supplied along the washing water supply pipe; a radionuclide analysis device equipped with a sample analysis chamber filled with collected samples and a radionuclide analysis unit that analyzes radionuclides among the samples within the sample analysis chamber, and analyzing radionuclides in water and air samples collected from water and air discharged from the drain of a canister; a water sample collection pipe branched to communicate with the drain pipe between the eleventh solenoid valve and the drain pump, connected to communicate with the inlet of the sample analysis chamber of the radionuclide analysis device, and supplying a water sample collected from the drain pipe into the sample analysis chamber of the radionuclide analysis device; and a twelfth solenoid valve mounted on the water sample collection pipe and opening and closing the water sample collection pipe; A primary pressure reducing exhaust pipe that branches off to communicate with the drain pipe between the branch point with the washing water supply pipe and the drain pump, and exhausts air discharged along the drain pipe into the exhaust system; a primary pressure reducing pump mounted on the primary pressure reducing exhaust pipe and installed on the primary pressure reducing exhaust pipe between the branch point with the drain pipe of the sixth solenoid valve that opens and closes the primary pressure reducing exhaust pipe, and pumps air inside the canister to be exhausted into the exhaust system through the drain pipe and the primary pressure reducing exhaust pipe; and a first air sample collection pipe that branches off from the primary pressure reducing exhaust pipe between the sixth solenoid valve and the primary pressure reducing pump, is connected to communicate with the sample analysis chamber of the radionuclide analyzer, and supplies an air sample collected from the primary pressure reducing exhaust pipe into the sample analysis chamber of the radionuclide analyzer. A seventh solenoid valve mounted on the first air sample collection tube and opening and closing the first air sample collection tube; a second pressure reduction exhaust pipe branched to communicate with a drain pipe between the branching point of the wash water supply pipe and the branching point of the first pressure reduction exhaust pipe, and exhausting air discharged along the drain pipe into an exhaust system;An eighth solenoid valve mounted on the secondary pressure reducing exhaust pipe and opening and closing the secondary pressure reducing exhaust pipe; a secondary pressure reducing pump mounted on the secondary pressure reducing exhaust pipe between the branching point with the drain pipe and the eighth solenoid valve, and pumping air inside the canister to be exhausted into the exhaust system through the drain pipe and the secondary pressure reducing exhaust pipe; a second air sample collection pipe branched from the secondary pressure reducing exhaust pipe between the eighth solenoid valve and the secondary pressure reducing pump, connected to communicate with the sample analysis chamber of the radionuclide analyzer, and supplying an air sample collected from the secondary pressure reducing exhaust pipe into the sample analysis chamber of the radionuclide analyzer; and a ninth solenoid valve mounted on the second air sample collection pipe and opening and closing the second air sample collection pipe; A radiation dose rate detection means mounted on a drain pipe between the branch point with the wash water supply pipe and the branch point with the secondary pressure reduction exhaust pipe, which detects the radioactivity rate of water and air discharged along the drain pipe through the drain pipe of the canister in real time and transmits the detected value; and a control unit each connected to the pressure sensing means, the radiation dose rate detection means, the radionuclide analyzer, the drain pump, the wash water supply pump, the primary and secondary pressure reduction pumps, and the second, sixth to ninth, tenth, eleventh, and thirteenth solenoid valves, and which controls the operation of the drain pump, the wash water supply pump, the primary and secondary pressure reduction pumps, and the second, sixth to ninth, tenth, eleventh, and thirteenth solenoid valves respectively, based on data received from the pressure sensing means, the radiation dose rate detection means, and the radionuclide analyzer and received operation commands;This can be achieved by a drying system for a canister loaded with spent nuclear fuel, characterized by comprising a display unit for displaying received information, an input unit for inputting operator commands, and an operation status display unit for outputting the system's operation status visually and audibly, and a control panel connected to the control unit that displays various information transmitted from the control unit on the display unit, outputs normal, abnormal, and emergency statuses during system operation to the operation status display unit, and transmits the operator's operation commands through the input unit to the control unit. Effects of the invention

[0032] The drying system for a canister loaded with spent nuclear fuel according to the present invention has the effect of safely and accurately implementing the applicant’s ‘method for drying a canister loaded with spent nuclear fuel’ while reliably preventing the disposal of a canister containing spent nuclear fuel with damaged cladding for an extended period by using a system that is simple in structure, small in volume, and inexpensive, while also checking in real time whether damage to the spent nuclear fuel cladding may occur due to differential pressure during the drying process, and immediately stopping the drying process for the corresponding canister and returning it to a temporary storage tank upon detection of damage. Brief explanation of the drawing

[0034] FIG. 1 is a flowchart illustrating the configuration of the present applicant's method for constructing a canister loaded with spent nuclear fuel, and FIG. 2 is a schematic diagram illustrating the configuration of a first embodiment of a drying system for a canister loaded with spent nuclear fuel according to the present invention and the mutual organic correlation between each component, and FIG. 3 is a schematic diagram illustrating the configuration of a second embodiment of a drying system for a canister loaded with spent nuclear fuel according to the present invention and the mutual organic correlation between each component, and FIG. 4 is a block diagram illustrating the components connected to the control unit and the mutual organic correlation between each component among the configurations of the first and second embodiments of the drying system for a canister loaded with spent nuclear fuel according to the present invention exemplified in FIG. 2 and FIG. 3. FIG. 5 is a schematic diagram illustrating the configuration of a second embodiment of a drying system for a canister loaded with spent nuclear fuel according to the present invention and the mutual organic correlation between each component, and FIG. 6 is a block diagram illustrating the components connected to the control unit and the mutual organic correlation between each component among the components of the configuration of the second embodiment of the drying system for a canister loaded with spent nuclear fuel according to the present invention exemplified in FIG. 5. FIG. 7 is a cross-sectional view illustrating the configuration of a radionuclide analyzer among the configurations of a drying system for a canister loaded with spent nuclear fuel according to the present invention. FIG. 8 is a cross-sectional view of the installation state showing a filtered residual material detection means in the configuration of a drying system for a canister loaded with spent nuclear fuel according to the present invention. Specific details for implementing the invention

[0035] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but can be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the invention of the scope and nature of the invention, and are limited by the claims of the present invention.

[0036] In describing the embodiments of the present invention, if it is determined that a detailed description of already known functions or configurations could unnecessarily obscure the essence of the invention, such detailed description will be omitted. Furthermore, the terms described below are defined considering the functions in the embodiments of the present invention, and these may vary depending on the intentions or conventions of the user or operator. Therefore, their definitions should be based on the content throughout this specification.

[0037] Hereinafter, a preferred embodiment of a drying system for a canister loaded with spent nuclear fuel according to the present invention will be described in detail with reference to the attached drawings.

[0038] Referring to the attached drawings FIGS. 2 to 8, the first to third embodiments of a drying system for a canister loaded with spent nuclear fuel according to the present invention, as clearly shown in FIG. 1, comprise: a canister draining step (S100) of measuring the internal pressure of the canister while simultaneously draining water filled inside the canister loaded with spent nuclear fuel to the outside through a drain port; and a canister preliminary depressurization drying step (S200) of maintaining the canister drain port in a closed state until the pressure inside the canister reaches a preliminary drying pressure value of 100 Torr, and exhausting the air inside the canister (air containing non-reactive gas and moisture) through an exhaust port to primarily depressurize and dry the interior of the canister. After the preliminary vacuum drying step (S200) of the canister is completed, a vacuum vaporization promotion step (S300) inside the canister in which the exhaust port of the canister is kept closed for a preset time so that moisture remaining inside the canister due to rapid vacuum reduction can be filled into the inner space of the canister to promote vacuum vaporization without freezing; and if the vacuum vaporization promotion step (S300) inside the canister is completed, a main vacuum drying step (S400) of the canister in which the air inside the canister is exhausted through the exhaust port of the canister until the pressure inside the canister reaches a preset main drying pressure value to secondarily vacuum dry the interior of the canister; If the main vacuum drying step (S400) of the above canister is completed, the exhaust port and drain port of the canister are kept closed, and the internal pressure measurement step (S500) of the canister is performed to measure the internal pressure of the canister for 30 minutes;A drying completion confirmation step (S600) of a canister in which, in the internal pressure measurement step (S500) of the canister, it is checked whether the internal pressure of the canister is less than the reference depressurization drying pressure of 3 Torr, and if the internal pressure inside the canister is greater than or equal to the reference depressurization drying pressure, the canister returns to the preliminary depressurization drying step (S200) of the canister; and a sealing step (S700) of a canister in which, in the drying completion confirmation step (S600), if the pressure inside the canister is less than the reference drying pressure of 3 Torr, a non-reactive gas is injected into the canister so that the cladding material of the spent nuclear fuel stored inside is not damaged by reacting with air, and the canister is tightly sealed so that leakage does not occur during the transport and storage of the canister; A radiation dose rate detection step (S800) that detects the radiation dose rate for water drained through the drain port of the canister and exhausted air in real time by operating a radiation dose rate detection means while any one of the drainage step (S100) of the canister, the preliminary vacuum drying step (S200) of the canister, and the main vacuum drying step (S400) of the canister, or both steps are being executed; a radiation dose rate verification step (S900) that checks whether the radiation dose rate for water and air detected in the radiation dose rate detection step (S800) is greater than or equal to a preset radiation dose rate, and if the detected radiation dose rate is less than the preset radiation dose rate, returns to the radiation dose rate detection step; and a sample collection and radionuclide analysis step (S1000) that, in the radiation dose rate verification step (S900), if the detected radiation dose rate is greater than or equal to the preset radiation dose rate, collects a water sample or an air sample and performs radionuclide analysis of the collected water sample or air sample using a radionuclide analyzer; A step for confirming whether evidence radionuclides of damage to spent nuclear fuel cladding are detected in the above sample collection and radionuclide analysis step (S1000), and if evidence radionuclides are not detected, a step for confirming damage to spent nuclear fuel cladding (S1100) that returns to the above radiation dose rate detection step;This is intended to safely and accurately implement the applicant’s method for transporting and storing radioactive waste, which comprises a step (S1100) for checking whether the spent nuclear fuel cladding is damaged, and if damage to the spent nuclear fuel cladding is confirmed, the execution of the step currently being executed among the draining step (S100) of the canister in which the damage to the spent nuclear fuel cladding is confirmed, the preliminary drying step (S200) of the canister in which the damage to the spent nuclear fuel cladding is confirmed, and a spent nuclear fuel cladding damage determination canister return step (S1200) of returning the canister in which the damage to the spent nuclear fuel cladding is confirmed to a temporary storage pool.

[0039] As clearly shown in the attached drawings FIGS. 2 and 4, the first embodiment of the drying system for a canister loaded with spent nuclear fuel according to the present invention is structured such that an air distribution device (20) is mounted on the exhaust port (10a) of the canister (10) to inject non-reactive gas (He) and perform decompression drying within the canister (10) through the exhaust port (10a), and to drain water collected within the canister (10) through the drain port (10b). The configuration comprises an air distribution device (20), first to fifth solenoid valves (EV1 to EV5), a pressure sensing means (PG), a non-reactive gas supply tank (300), a radionuclide analysis device (40), a primary decompression exhaust pipe (T2), a sixth solenoid valve (EV6), a primary decompression pump (PRP1), a first radiation dose rate detection means (RD1), and a first air sample It consists of a collection tube (AST1), a seventh solenoid valve (EV7), a secondary pressure relief exhaust pipe (T3), an eighth solenoid valve (EV8), a secondary pressure relief pump (PRP2), a second radiation dose rate detection means (RD2), a second air sample collection tube (AST2), a ninth solenoid valve (EV9), a drain pipe (T4), tenth and eleventh solenoid valves (EV10) (EV11), a drain pump (DP), a third radiation dose rate detection means (RD3), a water sample collection tube (WST1), a twelfth solenoid valve (EV12), a wash water supply tank (50), a first wash water supply pipe (WWT1), a thirteenth solenoid valve (EV13), a wash water supply pump (WWP), a second wash water supply pipe (WWT2), a control unit (60), and a control panel (70).

[0040] The above air distribution device (20) has first to fifth connectors (20a to 20e) and a pressure gauge mounting hole (20f), and as a distribution means for controlling the air flow path, the first connector is detachably connected to the exhaust port (10a) of the canister (10) so as to be connected to the inner hollow of the canister (10).

[0041] The first to fifth solenoid valves (EV1 to EV5) are each mounted on the first to fifth connectors (20a to 20e) of the air distribution device (20) and open and close the first to fifth connectors (20a to 20e).

[0042] The pressure sensing means (PG) is mounted in the pressure gauge mounting hole (20f) of the air distribution device (20) to sense the internal pressure of the canister (10) and transmit the pressure sensing value to the control unit (60).

[0043] The above non-reactive gas supply tank (30) is a tank having an exhaust port in which non-reactive gas is stored, and is connected to the second connector (20b) of the air distribution device (20) through the gas supply pipe (T1) so as to be connected to the non-reactive gas in the empty space where water in the canister (10) is drained, and the non-reactive gas is supplied and stopped in the canister (10) through the air distribution device (20) according to the opening and closing operation of the second solenoid valve (EV2).

[0044] The above-mentioned radionuclide analysis device (40) detects radioactive nuclides in air and water samples by collecting samples of air and water that are exhausted and drained through the exhaust port (10a) and drain port (10b) of the canister (10) during the drainage and depressurization drying process. It is equipped with a sample analysis chamber filled with the collected samples and a radionuclide analysis unit that analyzes the radionuclides in the samples within the sample analysis chamber. It analyzes the radionuclides in the collected air and water samples among the air and water discharged from the exhaust port (10a) and drain port (10b) of the canister (10). As clearly shown in the attached drawing Fig. 7, it is composed of a sample analysis chamber (41), a water level detection means (42), a pressure detection means (43), an inlet solenoid valve (IV1)(IV2), an outlet solenoid valve (OV1)(OV2), and a radionuclide analysis unit (44).

[0045] The sample analysis chamber (41) is a transparent tube shape having an internal hollow, and has two inlets (41a) (41b) formed on the top surface to receive a water sample or an air sample in the internal hollow, two outlets (41c) (41d) formed on the bottom surface to discharge the water sample or an air sample received in the internal hollow to the outside, and a solid scintillator layer (41e) which is mounted in close contact on the inner surface and emits fine visible light by colliding with radiation emitted as a radionuclide contained in the water or air sample filled in the internal hollow decays.

[0046] The above inlet solenoid valves (IV1) and (IV2) are each mounted on the two inlets (41a) and (41b) of the sample analysis chamber (41) to be connected to the control unit (60), and each open and close the two inlets (41a) and (41b).

[0047] The above-mentioned exhaust solenoid valves (OV1) and (OV2) are each mounted on the two exhaust ports (41c) and (41d) of the sample analysis chamber (41) to be connected to the control unit (60), and each open and close the two exhaust ports (41c) and (41d).

[0048] The above-mentioned water level detection means (42) is mounted on the end side of the sample analysis chamber (41) to be connected to the control unit (60), detects the water level inside the sample analysis chamber (41), and transmits the water level detection signal. That is, when the water level of the water sample in the sample analysis chamber (41) reaches a preset water level, it detects this and transmits the water level detection signal to the control unit (60), and the control unit (60), upon receiving the water level detection signal, closes the inlet solenoid valve (IV1) to block the water sample from flowing into the sample analysis chamber (41).

[0049] The pressure sensing means (43) is mounted on the sample analysis chamber (41) to be connected to the control unit (60), detects the pressure inside the sample analysis chamber (41), and transmits the pressure signal. That is, when the pressure inside the sample analysis chamber (41) reaches a preset pressure, it detects this and transmits the pressure sensing signal to the control unit (60), and the control unit (60), upon receiving the pressure sensing signal, closes the inlet solenoid valve (IV2) to block the air sample from flowing into the sample analysis chamber (41).

[0050] The above radionuclide analysis unit (44) is mounted in close contact on the opposite outer surface of the sample analysis chamber (41) so as to be connected to the control unit (60), and has a plurality of optical sensors that detect visible light emitted from the solid scintillator layer (41e) and transmit the detection signal, analyzes radioactive nuclides based on the visible light detection signal transmitted from the optical sensors, and transmits the radioactive nuclide analysis data to the control unit (60).

[0051] The above primary depressurization exhaust pipe (T2)) is connected to the third connector (20c) of the air distribution device (20) and exhausts the air inside the canister (10) to the exhaust system.

[0052] The sixth solenoid valve (EV6) is mounted on the exhaust system side end of the primary pressure reduction exhaust pipe (T2) and opens and closes the exhaust system side end of the primary pressure reduction exhaust pipe (T2).

[0053] The above primary pressure reducing pump (PRP1) is mounted on the primary pressure reducing exhaust pipe (T2) between the third and sixth solenoid valves (EV3) (EV6) and pumps the air in the canister (10) to be exhausted through the primary pressure reducing exhaust pipe (T2) to the exhaust system.

[0054] The first radiation dose rate detection means (RD1) is mounted on the primary pressure reduction exhaust pipe (T2) between the third solenoid valve (EV3) and the primary pressure reduction pump (PRP1) so as to be connected to the control unit (60), and detects the radiation dose rate of the air exhausted into the exhaust system along the primary pressure reduction exhaust pipe (T2) in real time and transmits the detected value.

[0055] The first air sample collection tube (AST1) is branched to communicate with the primary pressure exhaust pipe between the sixth solenoid valve and the primary pressure pump, and is connected to communicate with the inlet of the sample analysis chamber of the radionuclide analysis device (40), and supplies the air sample collected from the primary pressure exhaust pipe into the sample analysis chamber of the radionuclide analysis device (40).

[0056] The above-mentioned seventh solenoid valve (EV7) is mounted on the above-mentioned first air sample collection tube (AST1) and opens and closes the above-mentioned first air sample collection tube (AST1).

[0057] The above secondary pressure reduction exhaust pipe (T3) is connected to the fourth connector of the air distributor device and exhausts the air inside the canister (10) to the exhaust system.

[0058] The above-mentioned eighth solenoid valve (EV8) is mounted on the exhaust system side end of the above-mentioned secondary pressure reduction exhaust pipe (T3) and opens and closes the exhaust system side end of the above-mentioned primary pressure reduction exhaust pipe (T3).

[0059] The secondary pressure reducing pump (PRP2) is mounted on the secondary pressure reducing exhaust pipe (T3) between the fourth and eighth solenoid valves (EV4) (EV8) and pumps the air in the canister (10) to be exhausted through the secondary pressure reducing exhaust pipe (T3) to the exhaust system.

[0060] The second radiation dose rate detection means (RD2) is mounted on the secondary pressure reduction exhaust pipe (T3) between the fourth solenoid valve (EV4) and the secondary pressure reduction pump (PRP2), detects the radiation dose rate of the air exhausted into the exhaust system along the secondary pressure reduction exhaust pipe (T3) in real time, and transmits the detected value.

[0061] The second air sample collection tube (AST2) is branched to communicate with the second pressure exhaust pipe (T3) between the eighth solenoid valve (EV8) and the second pressure reduction pump (PRP2), and is connected to communicate with the inlet of the sample analysis chamber of the radionuclide analysis device (40), and supplies the air sample collected from the second pressure exhaust pipe (T3) into the sample analysis chamber of the radionuclide analysis device (40).

[0062] The ninth solenoid valve (EV9) is mounted on the second air sample collection tube (AST2) and opens and closes the second air sample collection tube (AST2).

[0063] The above drain pipe (T4) is detachably connected to the drain port (10b) of the canister (10) and drains the water filled in the canister (10) into the drainage system.

[0064] The above 10th and 11th solenoid valves (EV10) and (EV11) are each mounted on both ends of the drain pipe (T4) and each open and close both ends of the drain pipe (T4).

[0065] The above drainage pump (DP) is mounted on the drain pipe (T4) between the 10th and 11th solenoid valves (EV10) (EV11) and pumps and drains the water filled in the canister (10).

[0066] The above-mentioned third radiation dose rate detection means (RD3) is mounted on the drain pipe (T4) between the above-mentioned first solenoid valve (EV10) and the drain pump (DP), detects the radiation dose rate of the water drained along the drain pipe (T4) in real time, and transmits the detected value.

[0067] The above water sample collection tube (WST1) is branched out to communicate with the drain pipe (T4) between the 11th solenoid valve (EV11) and the drain pump (DP), and is connected to communicate with the inlet of the sample analysis chamber of the radionuclide analysis device (40), and supplies the water sample collected from the drain pipe (T4) into the sample analysis chamber of the radionuclide analysis device (40).

[0068] The above 12th solenoid valve (EV12) is mounted on the water sample collection tube (WST1) and opens and closes the water sample collection tube (WST1).

[0069] The above washing water supply tank (50) is a tank having a drain where washing water is stored, and washes by supplying washing water into the above primary and secondary pressure relief exhaust pipes (T2) (T3) and the above drain pipe (T4).

[0070] The first washing water supply pipe (WWT1) is branched to communicate with the drain pipe (T4) between the 10th solenoid valve (EV10) and the 3rd radiation dose rate detection means (RD3), and is connected to communicate with the drain of the washing water supply tank (50) to supply washing water into the drain pipe (T4).

[0071] The above 13th solenoid valve (EV13) is mounted on the above 1st washing water supply pipe (WWT1) and opens and closes the above 1st washing water supply pipe (WWT1).

[0072] The above washing water supply pump (WWP) is mounted on the first washing water supply pipe (WWT1) between the washing water supply tank (50) and the 13th solenoid valve (EV13), and pumps the washing water in the washing water supply tank (50).

[0073] The second washing water supply pipe (WWT2) is branched from the first washing water supply pipe (WWT1) between the washing water supply pump (WWP) and the 13th solenoid valve (EV13) and is connected to the 5th connector (20e) of the air distribution device (20) to supply washing water into the first and second pressure reduction exhaust pipes (T2) (T3).

[0074] The control unit (60) is connected to the pressure sensing means (PG), the first to third radiation dose rate detection means (RD1 to RD3), the radionuclide analysis device (40), the first and second pressure reduction pumps (PRP1) (PRP2), the drainage pump (DP), the wash water supply pump (WWP), and the first to thirteenth solenoid valves (EV1 to EV13), respectively, and controls the operation of the first and second pressure reduction pumps (PRP1) (PRP2), the drainage pump (DP), the wash water supply pump (WWP), and the first to thirteenth solenoid valves (EV1 to EV13) respectively based on data received from the pressure sensing means (PG), the first to third radiation dose rate detection means (RD1 to RD3) and the radionuclide analysis device (40) and operation commands received.

[0075] The above control panel (70) is equipped with a display unit for displaying received information, an input unit for inputting commands from an operator, and an operation status display unit for outputting the operation status of the system visually and audibly. It is connected to the control unit (60) to display various information transmitted from the control unit (60) on the display unit, output normal, abnormal, and emergency statuses during system operation to the operation status display unit, and transmit the operator's operation commands to the control unit (60) through the input unit.

[0077] Referring to the attached drawings FIG. 3 and 4, a second embodiment of a drying system for a canister loaded with spent nuclear fuel according to the present invention is structured such that an air distribution device (20) is installed in the drain port (10b) of the canister (10) to drain water accumulated in the canister (10) through the drain port (10b) and to perform depressurized drying in the canister (10), and to inject a non-reactive gas (He) into the canister (10) through the exhaust port (10a). The configuration comprises an air distribution device (20), first to fifth solenoid valves (EV1 to EV5), a pressure sensing means (PG), a non-reactive gas supply tank (30), a thirteenth solenoid valve (EV13), a radionuclide analysis device (40), a drain pipe (T4), an eleventh solenoid valve (EV11), a drainage pump (DP), and a third radiation dose rate It consists of a detection means (RD3), a water sample collection tube (WST), a 13th solenoid valve (EV13), a primary pressure relief exhaust pipe (T2), a 6th solenoid valve (EV6), a primary pressure relief pump (PRP1), a first radiation dose rate detection means (RD1), a first air sample collection tube (AST1), a 7th solenoid valve (EV7), a secondary pressure relief exhaust pipe (T3), an 8th solenoid valve (EV8), a secondary pressure relief pump (PRP2), a second radiation dose rate detection means (RD2), a second air sample collection tube (AST2), a 9th solenoid valve (EV9), a wash water supply tank (50), a 13th solenoid valve (EV13), a wash water supply pump (WWP), a control unit (60), and a control panel (70).

[0078] The above air distribution device (20) has first to fifth connectors (20a to 20e) and a pressure gauge mounting hole (20f), and as a distribution means for controlling the air flow path, the first connector is detachably connected to the drain (10b) of the canister (10) so as to be connected to the inner hollow of the canister (10).

[0079] The first to fifth solenoid valves (EV1 to EV5) are each mounted on the first to fifth connectors (20a to 20e) of the air distribution device (20) and open and close the first to fifth connectors (20a to 20e).

[0080] The pressure sensing means (PG) is mounted in the pressure gauge mounting hole (20f) of the air distribution device (20) to sense the internal pressure of the canister (10) and transmit the pressure sensing value.

[0081] The above non-reactive gas supply tank (30) is a tank having an exhaust port in which non-reactive gas is stored, and is connected to the exhaust port (10a) of the canister (10) through the gas supply pipe (T1), and the non-reactive gas is supplied and stopped in the canister (10) through the air distribution device (20) according to the opening and closing operation of the second solenoid valve (EV2) so that the non-reactive gas is filled into the empty space where the water in the canister (10) is drained.

[0082] The above 13th solenoid valve (EV13) is mounted on the gas supply pipe (T1) and opens and closes the gas supply pipe (T1).

[0083] The above-mentioned radionuclide analysis device (40) detects radioactive nuclides in air and water samples collected from air and water that are exhausted and drained through the drain port (10b) of the canister (10) during the drainage and depressurization drying process. It is equipped with a sample analysis chamber filled with the collected samples and a radionuclide analysis unit that analyzes the radionuclides in the samples within the sample analysis chamber. It analyzes the radionuclides in the air and water samples collected from the air and water discharged from the drain port (10b) of the canister (10). As clearly shown in the attached drawing Fig. 7, it is composed of a sample analysis chamber (41), a water level detection means (42), a pressure detection means (43), an inlet solenoid valve (IV1)(IV2), an outlet solenoid valve (OV1)(OV2), and a radionuclide analysis unit (44).

[0084] The sample analysis chamber (41) is a transparent tube shape having an internal hollow, and has two inlets (41a) (41b) formed on the top surface to receive a water sample or an air sample in the internal hollow, two outlets (41c) (41d) formed on the bottom surface to discharge the water sample or an air sample received in the internal hollow to the outside, and a solid scintillator layer (41e) which is mounted in close contact on the inner surface and emits fine visible light by colliding with radiation emitted as a radionuclide contained in the water or air sample filled in the internal hollow decays.

[0085] The above inlet solenoid valves (IV1) and (IV2) are each mounted on the two inlets (41a) and (41b) of the sample analysis chamber (41) to be connected to the control unit (60), and each open and close the two inlets (41a) and (41b).

[0086] The above-mentioned exhaust solenoid valves (OV1) and (OV2) are each mounted on the two exhaust ports (41c) and (41d) of the sample analysis chamber (41) to be connected to the control unit (60), and each open and close the two exhaust ports (41c) and (41d).

[0087] The above-mentioned water level detection means (42) is mounted on the end side of the sample analysis chamber (41) to be connected to the control unit (60), detects the water level inside the sample analysis chamber (41), and transmits the water level detection signal. That is, when the water level of the water sample in the sample analysis chamber (41) reaches a preset water level, it detects this and transmits the water level detection signal to the control unit (60), and the control unit (60), upon receiving the water level detection signal, closes the inlet solenoid valve (IV1) to block the water sample from flowing into the sample analysis chamber (41).

[0088] The pressure sensing means (43) is mounted on the sample analysis chamber (41) to be connected to the control unit (60), detects the pressure inside the sample analysis chamber (41), and transmits the pressure signal. That is, when the pressure inside the sample analysis chamber (41) reaches a preset pressure, it detects this and transmits the pressure sensing signal to the control unit (60), and the control unit (60), upon receiving the pressure sensing signal, closes the inlet solenoid valve (IV2) to block the air sample from flowing into the sample analysis chamber (41).

[0089] The above radionuclide analysis unit (44) is mounted in close contact on the opposite outer surface of the sample analysis chamber (41) so as to be connected to the control unit (60), and has a plurality of optical sensors that detect visible light emitted from the solid scintillator layer (41e) and transmit the detection signal, analyzes radioactive nuclides based on the visible light detection signal transmitted from the optical sensors, and transmits the radioactive nuclide analysis data to the control unit (60).

[0090] The above drain pipe (T4) is connected to the third connector (210c) of the air distribution device (20) and drains the water in the canister (10) into the drainage system.

[0091] The above 11th solenoid valve (EV11) is mounted on the drain pipe (T4) and opens and closes the drain (T4).

[0092] The above drainage pump (DP) is mounted on the drain pipe (T4) between the first solenoid valve (EV11) and the third solenoid valve (EV3) of the third connector (20c) of the air distribution device (20), and pumps the water filled in the canister (10) so that it is discharged through the drain port (10b) and drained into the drainage system along the drain pipe (T4).

[0093] The above-mentioned third radiation dose rate detection means (RD3) is mounted on the drain pipe (T4) between the drain pump (DP) and the third solenoid valve (EV3), detects the radiation dose rate of the water drained along the drain pipe (T4) in real time, and transmits the detected value.

[0094] The above water sample collection tube (WST) is branched out to communicate with the drain pipe (T4) between the drain pump (DP) and the 11th solenoid valve (EV11), and is connected to communicate with the inlet of the sample analysis chamber of the radionuclide analysis device (40), and supplies the water sample collected from the drain pipe (T4) into the sample analysis chamber of the radionuclide analysis device (40).

[0095] The above 13th solenoid valve (EV13) is mounted on the water sample collection tube (WST) and opens and closes the water sample collection tube (WST).

[0096] The above primary depressurization exhaust pipe (T2) is connected to the fourth connector (20d) of the air distribution device (20) and exhausts the air inside the canister (10) to the exhaust system.

[0097] The above-mentioned sixth solenoid valve (EV6) is mounted on the above-mentioned primary pressure reduction exhaust pipe (T2) and opens and closes the above-mentioned primary pressure reduction exhaust pipe (T2).

[0098] The above primary pressure reducing pump (PRP1) is mounted on the primary pressure reducing exhaust pipe (T2) between the sixth solenoid valve (EV6) and the fourth solenoid valve (EV4) of the fourth connector (20d) of the air distribution device (20), and pumps the air inside the canister (10) to be exhausted to the exhaust system through the primary pressure reducing exhaust pipe (T2).

[0099] The first radiation dose rate detection means (RD1) is mounted on the primary pressure reduction exhaust pipe (T2) between the fourth solenoid valve (EV4) of the fourth connector (20d) of the air distribution device (20) and the primary pressure reduction pump (PRP1) so as to be connected to the control unit (60), and detects the radiation dose rate of the air exhausted into the exhaust system along the primary pressure reduction exhaust pipe (T2) in real time and transmits the detected value to the control unit (60).

[0100] The first air sample collection tube (AST1) is branched to communicate with the primary pressure exhaust pipe (T2) between the primary pressure pump (PRP1) and the sixth solenoid valve (EV6), and is connected to communicate with the inlet of the sample analysis chamber of the radionuclide analysis device (40), and supplies the air sample collected from the primary pressure exhaust pipe (T2) into the sample analysis chamber of the radionuclide analysis device (40).

[0101] The above-mentioned seventh solenoid valve (EV7) is mounted on the above-mentioned first air sample collection tube (AST1) and opens and closes the above-mentioned first air sample collection tube (AST1).

[0102] The above secondary pressure reduction exhaust pipe (T3) is connected to the fifth connector (20e) of the air distribution device (20) and exhausts the air inside the canister (10) to the exhaust system.

[0103] The above-mentioned eighth solenoid valve (EV8) is mounted on the above-mentioned secondary pressure reduction exhaust pipe (T3) and opens and closes the above-mentioned secondary pressure reduction exhaust pipe (T3).

[0104] The above secondary pressure reducing pump (PRP2) is mounted on the secondary pressure reducing exhaust pipe (T3) between the eighth solenoid valve (EV8) and the fifth solenoid valve (EV5) of the fifth connector (20e) of the air distribution device (20), and pumps the air inside the canister (10) to be exhausted to the exhaust system through the secondary pressure reducing exhaust pipe (T3).

[0105] The second radiation dose rate detection means (RD2) is mounted on the second pressure reduction exhaust pipe (T3) between the fifth solenoid valve (EV5) of the fifth connector (20e) of the air distribution device (20) and the second pressure reduction pump (PRP2) so as to be connected to the control unit (60), and detects the radiation dose rate of the air exhausted into the exhaust system along the second pressure reduction exhaust pipe (T3) in real time and transmits the detected value to the control unit (60).

[0106] The second air sample collection tube (AST2) is branched to communicate with the second pressure exhaust pipe (T3) between the second pressure reduction pump (PRP2) and the eighth solenoid valve (EV8), and is connected to communicate with the inlet of the sample analysis chamber of the radionuclide analysis device (40), and supplies the air sample collected from the second pressure exhaust pipe (T3) into the sample analysis chamber of the radionuclide analysis device (40).

[0107] The ninth solenoid valve (EV9) is mounted on the second air sample collection tube (AST2) and opens and closes the second air sample collection tube (AST2).

[0108] The above washing water supply tank (50) is a tank having a drain where washing water is stored, and is connected to the second connector (20b) of the air distribution device (20) by the washing water supply pipe (WWT), and washes by supplying washing water into the drain pipe (T4) and the primary and secondary pressure reduction exhaust pipes (T2) (T3) by the opening and closing operation of the second solenoid valve (EV2).

[0109] The above washing water supply pump (WWP) is mounted on the washing water supply pipe (WWT) between the second solenoid valve (EV2) and the washing water supply tank (50), and pumps the washing water in the washing water supply tank (50).

[0110] The control unit (60) controls the operation of the primary and secondary pressure reduction pumps (PRP1) (PRP2), drainage pump (DP), wash water supply pump (WWP), primary to ninth solenoid valves (EV1 to EV9), and eleventh to eleventh solenoid valves (EV11 to EV13) respectively, based on data received from the pressure detection means (PG), primary to third radiation dose rate detection means (RD1 to RD3), radionuclide analysis device (40), and operation commands received from the pressure detection means (PG), primary to third radiation dose rate detection means (RD1 to RD3), and radionuclide analysis device (40).

[0111] The above control panel (70) is equipped with a display unit for displaying received information, an input unit for inputting commands from a worker, and an operation status display unit for outputting the operation status of the system visually and audibly. It is connected to the control unit (60) to display various information transmitted from the control unit (60) on the display unit, output normal, abnormal, and emergency statuses during system operation to the operation status display unit, and transmit the worker's operation commands through the input unit to the control unit (60).

[0113] Referring to the attached drawings FIG. 5 and 6, the third embodiment of the drying system for a canister loaded with spent nuclear fuel according to the present invention is configured to inject a non-reactive gas (He) into the canister (10) through the exhaust port (10a) of the canister (10) without using an air distribution device (20), and to drain the water filled in the canister (10) through the drain port (10b) and perform a depressurized drying process within the canister (10), while enabling the detection of radiation dose rates for water and air samples using only a single reflected dose rate detection means (RD). The configuration comprises a non-reactive gas supply tank (30), a pressure sensing means (PG), a 13th solenoid valve (EV13), a drain pipe (T4), 10th and 11th solenoid valves (EV10) (EV11), a drain pump (DP), a washing water supply tank (30), and washing water It consists of a supply pipe (WWT), a second solenoid valve (EV2), a wash water supply pump (WWP), a radionuclide analyzer (40), a water sample collection pipe (WST), a 12th solenoid valve (EV12), a primary depressurization exhaust pipe (T2), a 6th solenoid valve (EV6), a primary depressurization pump (PRP1), a first air sample collection pipe (AST1), a 7th solenoid valve (EV7), a secondary depressurization exhaust pipe (T3), an 8th solenoid valve (EV8), a secondary depressurization pump (PRP2), a 2nd air sample collection pipe (AST2), a 9th solenoid valve (EV9), a radiation dose rate detection means (RD), a control unit (60), and a control panel (70).

[0114] The above-mentioned non-reactive gas supply tank (30) is a tank having an exhaust port in which non-reactive gas is stored, and is connected to the exhaust port (10a) of the canister (10) through a gas supply pipe (T1) so as to be in communication with the canister (10), and supplies non-reactive gas into the canister (10) so that the non-reactive gas is filled into the empty space where the water inside the canister (10) is drained.

[0115] The pressure sensing means (PG) is mounted on the gas supply pipe (T1), detects the internal pressure of the canister (10), and transmits the detected pressure value.

[0116] The above 13th solenoid valve (EV13) is mounted on the gas supply pipe (T1) between the pressure sensing means (PG) and the non-reactive gas supply tank (20), and opens and closes the gas supply pipe (T1).

[0117] The above drain pipe (T4) is detachably connected to the drain port (10b) of the canister (10) and drains the water filled in the canister (10) into the drainage system.

[0118] The above 10th and 11th solenoid valves (EV10) and (EV11) are each mounted on both ends of the drain pipe (T4) and each open and close both ends of the drain pipe (T4).

[0119] The above drainage pump (DP) is mounted on the drain pipe (T4) between the 10th and 11th solenoid valves (EV10) (EV11) and pumps and drains the water filled in the canister (10).

[0120] The above-mentioned washing water supply tank (30) is a tank having a drain where washing water is stored, and washes by supplying washing water into the flow path of water and air discharged through the drain (10b) of the canister (10).

[0121] The above washing water supply pipe (WWT) is branched out to communicate with the drain pipe (T4) between the 10th and 11th solenoid valves (EV10) (EV11) and is connected to communicate with the drain of the washing water supply tank (30) to supply washing water into the drain pipe (T4).

[0122] The second solenoid valve (EV2) is mounted on the washing water supply pipe (WWT) and opens and closes the washing water supply pipe (WWT).

[0123] The above washing water supply pump (WWP) is mounted on the washing water supply pipe (WWT) between the second solenoid valve (EV2) and the drain of the washing water supply tank (50), and pumps the washing water in the washing water supply tank (50) so that washing water is supplied along the washing water supply pipe (WWT).

[0124] As clearly shown in the attached drawing Fig. 7, the above-mentioned radionuclide analysis device (40) detects radioactive nuclides in air and water samples discharged through the drain port (10b) of the canister (10) during the drainage and depressurization drying process, and is equipped with a sample analysis chamber filled with collected samples and a radionuclide analysis unit that analyzes radionuclides in the samples within the sample analysis chamber, and analyzes radionuclides in air and water samples collected from the air and water discharged from the drain port (10b) of the canister (10). As clearly shown in the attached drawing Fig. 7, it is composed of a sample analysis chamber (41), a water level detection means (42), a pressure detection means (43), an inlet solenoid valve (IV1)(IV2), an outlet solenoid valve (OV1)(OV2), and a radionuclide analysis unit (44).

[0125] The sample analysis chamber (41) is a transparent tube shape having an internal hollow, and has two inlets (41a) (41b) formed on the top surface to receive a water sample or an air sample in the internal hollow, two outlets (41c) (41d) formed on the bottom surface to discharge the water sample or an air sample received in the internal hollow to the outside, and a solid scintillator layer (41e) which is mounted in close contact on the inner surface and emits fine visible light by colliding with radiation emitted as a radionuclide contained in the water or air sample filled in the internal hollow decays.

[0126] The above inlet solenoid valves (IV1) and (IV2) are each mounted on the two inlets (41a) and (41b) of the sample analysis chamber (41) to be connected to the control unit (60), and each open and close the two inlets (41a) and (41b).

[0127] The above-mentioned exhaust solenoid valves (OV1) and (OV2) are each mounted on the two exhaust ports (41c) and (41d) of the sample analysis chamber (41) to be connected to the control unit (60), and each open and close the two exhaust ports (41c) and (41d).

[0128] The above-mentioned water level detection means (42) is mounted on the end side of the sample analysis chamber (41) to be connected to the control unit (60), detects the water level inside the sample analysis chamber (41), and transmits the water level detection signal. That is, when the water level of the water sample in the sample analysis chamber (41) reaches a preset water level, it detects this and transmits the water level detection signal to the control unit (60), and the control unit (60), upon receiving the water level detection signal, closes the inlet solenoid valve (IV1) to block the water sample from flowing into the sample analysis chamber (41).

[0129] The pressure sensing means (43) is mounted on the sample analysis chamber (41) to be connected to the control unit (60), detects the pressure inside the sample analysis chamber (41), and transmits the pressure signal. That is, when the pressure inside the sample analysis chamber (41) reaches a preset pressure, it detects this and transmits the pressure sensing signal to the control unit (60), and the control unit (60), upon receiving the pressure sensing signal, closes the inlet solenoid valve (IV2) to block the air sample from flowing into the sample analysis chamber (41).

[0130] The above radionuclide analysis device (44) is mounted in close contact on the opposite outer surface of the sample analysis chamber (41) so as to be connected to the control unit (60), and has a plurality of optical sensors that detect visible light emitted from the solid scintillator layer (41e) and transmit the detection signal, analyzes radioactive nuclides based on the visible light detection signal transmitted from the optical sensors, and transmits the radioactive nuclide analysis data to the control unit (60).

[0131] The above water sample collection tube (WST) is branched out to communicate with the drain pipe (T4) between the 11th solenoid valve (EV11) and the drain pump (DP), and is connected to communicate with the inlet of the sample analysis chamber of the radionuclide analysis device (40), and supplies the water sample collected from the drain pipe (T4) into the sample analysis chamber of the radionuclide analysis device (40).

[0132] The above 12th solenoid valve (EV12) is mounted on the water sample collection tube (WST) and opens and closes the water sample collection tube (WST).

[0133] The above primary pressure reduction exhaust pipe (T2) is branched to communicate with the drain pipe (T4) between the branch point with the washing water supply pipe (WWT) and the drain pump (DP), and exhausts the air discharged along the drain pipe (T4) into the exhaust system.

[0134] The above-mentioned sixth solenoid valve (EV6) is mounted on the above-mentioned primary pressure reduction exhaust pipe (T2) and opens and closes the above-mentioned primary pressure reduction exhaust pipe (T2).

[0135] The above primary pressure reducing pump (PRP1) is mounted on the primary pressure reducing exhaust pipe (T2) between the branch point with the drain pipe (T4) and the sixth solenoid valve (EV6), and pumps the air inside the canister (10) to be exhausted into the exhaust system through the drain pipe (T4) and the primary pressure reducing exhaust pipe (T2).

[0136] The first air sample collection tube (AST1) is branched from the primary pressure relief exhaust pipe (T2) between the sixth solenoid valve (EV6) and the primary pressure relief pump (PRP1) and is connected to the sample analysis chamber of the radionuclide analysis device (40), and supplies the air sample collected from the primary pressure relief exhaust pipe (T2) into the sample analysis chamber of the radionuclide analysis device (40).

[0137] The above-mentioned seventh solenoid valve (EV7) is mounted on the above-mentioned first air sample collection tube (AST1) and opens and closes the above-mentioned first air sample collection tube (AST1).

[0138] The above secondary pressure reduction exhaust pipe (T3) is connected to the drain pipe (T4) between the branch point of the washing water supply pipe (WWT) and the branch point of the primary pressure reduction exhaust pipe (T2), and exhausts the air discharged along the drain pipe (T4) into the exhaust system.

[0139] The above-mentioned eighth solenoid valve (EV8) is mounted on the above-mentioned secondary pressure reduction exhaust pipe (T3) and opens and closes the above-mentioned secondary pressure reduction exhaust pipe (T3).

[0140] The above secondary pressure reducing pump (PRP2) is mounted on the secondary pressure reducing exhaust pipe (T3) between the branch point with the drain pipe (T4) and the eighth solenoid valve (EV8), and pumps the air inside the canister (10) to be exhausted into the exhaust system through the drain pipe (T4) and the secondary pressure reducing exhaust pipe (T3).

[0141] The second air sample collection tube (AST2) is branched from the secondary pressure exhaust pipe (T3) between the eighth solenoid valve (EV8) and the secondary pressure reduction pump (PRP2) and is connected to the sample analysis chamber of the radionuclide analysis device (40), and supplies the air sample collected from the secondary pressure exhaust pipe (T3) into the sample analysis chamber of the radionuclide analysis device (40).

[0142] The ninth solenoid valve (EV9) is mounted on the second air sample collection tube (AST2) and opens and closes the second air sample collection tube (AST2).

[0143] The radiation dose rate detection means (RD) is mounted on the drain pipe (T4) between the branch point with the wash water supply pipe (WWT) and the branch point with the secondary depressurization exhaust pipe (T3), and detects the radiation dose rate of water and air discharged along the drain pipe (T4) through the drain pipe (10b) of the canister (10) in real time and transmits the detected value.

[0144] The control unit (60) is connected to the pressure sensing means (PG), radiation dose rate detection means (RD), radionuclide analysis device (40), drainage pump (DP), wash water supply pump (WWP), primary and secondary pressure reduction pumps (PRP1) (PRP2), and the second, sixth to ninth, tenth, eleventh, and thirteenth solenoid valves (EV2) (EV6 to EV9) (EV10) (EV11) (EV13), respectively, and operates the drainage pump (DP), wash water supply pump (WWP), primary and secondary pressure reduction pumps (PRP1) (PRP2), and the second, sixth to ninth, tenth, eleventh, and thirteenth solenoid valves (EV2) (EV6 to EV9) (EV10) (EV11) (EV13) based on data received from the pressure sensing means (PG), radiation dose rate detection means (RD), and radionuclide analysis device (40) and the received operation command. Each controls it.

[0145] The above control panel (70) is equipped with a display unit for displaying received information, an input unit for inputting commands from a worker, and an operation status display unit for outputting the operation status of the system visually and audibly. It is connected to the control unit (60) to display various information transmitted from the control unit (60) on the display unit, output normal, abnormal, and emergency statuses during system operation to the operation status display unit, and transmit the worker's operation commands through the input unit to the control unit (60).

[0147] In addition, the first to third embodiments of the drying system for a canister loaded with spent nuclear fuel according to the present invention further include a filtered residual material detection means (FRD) to check whether the cladding of the spent nuclear fuel loaded inside the canister (10) is damaged during the drainage and depressurization drying process.

[0148] As clearly shown in FIG. 8 of the attached drawings, the above filter residue detection means (FRD) is respectively mounted on the primary pressurized exhaust pipe (T2) between the 6th solenoid valve (EV6) and the exhaust system, the secondary depressurized exhaust pipe (T3) between the 8th solenoid valve (EV8) and the exhaust system, and the drain pipe (T4) between the 11th solenoid valve (EV11) and the drainage system so as to be connected to the control unit (60). It filters filter residues in the air exhausted into the exhaust system through the primary and secondary pressurized exhaust pipes (T2) and (T3) and filter residues in the water drained into the drainage system through the drain pipe (T4), and at the same time, captures an image of the residue on the filter to monitor the presence of residues on the filter, transmits the acquired image to the control unit (60) so that it is displayed on the display of the control panel (70), and allows the operator to check whether the spent nuclear fuel cladding is damaged through the acquired image on the display of the control panel (70). As clearly shown in FIG. 8 of the attached drawings Together, the configuration consists of a housing (F1), a filter material (F2), a camera means (F3), and a lamp means (F4).

[0149] The above housing (F1) has a hollow interior and has connecting parts at both ends so that it can be mounted in communication with the drain pipe and exhaust pipe.

[0150] The above filter material (F2) is a filter that is embedded within the housing (F1) and filters water and air to remove residual substances (materials of evidence of damage that can confirm damage to spent nuclear fuel cladding) that may be contained in the water and air.

[0151] The above camera means (F3) is connected to the control unit (60) and is embedded in the housing (F1) to photograph the front surface of the filter material (F2), and transmits the captured image to the control unit (60).

[0152] The lamp means (F4) is connected to the control unit (60) and is embedded in the housing (F1) to illuminate the front surface of the filter material (F2).

[0154] The drying system for a canister loaded with spent nuclear fuel according to the present invention, having the configuration as described above, has the advantage of being able to perform a depressurized drying process inside a canister containing spent nuclear fuel using a system that is simple in configuration, small in volume, and inexpensive, while also checking in real time whether damage to the spent nuclear fuel cladding may occur due to differential pressure during the depressurized drying process, and immediately stopping the depressurized drying process for the corresponding canister and returning it to a temporary storage tank upon confirmation of damage, thereby reliably preventing the disposal of a canister containing spent nuclear fuel with damaged cladding for an extended period, and safely and accurately implementing the applicant's 'method for drying a canister loaded with spent nuclear fuel'.

[0156] As such, those skilled in the art to which the present invention pertains will understand that the technical configuration of the present invention described above can be implemented in other specific forms without altering the technical concept or essential features of the present invention.

[0157] Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting, and the scope of the invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts thereof should be interpreted as being included within the scope of the invention. Explanation of the symbols

[0159] 20: Air distribution unit EV1~EV13: Solenoid valve PG: Pressure sensing means 30: Non-reactive gas supply tank 40: Nuclide analyzer T1: Gas supply pipe T2: Primary pressure reducing exhaust pipe T3: Secondary pressure reducing exhaust pipe T4: Drain pipe PRP1: Primary pressure reducing pump PRP2: Secondary vacuum pump AST1: First air sample collection tube RD, RD1, RD2, RD3: Radiation dose rate detection means AST2: First air sample collection tube DP: Drainage pump WST1: Water sample collection tube 50: Wash water supply tank FRD: Filtration residue detection means WWT1: 1st wash water supply pipe WWT2: 2nd wash water supply pipe WWP: Wash water supply pump 60: Control unit 70: Control panel

Claims

Claim 1 A drainage step (S100) of a canister in which the internal pressure of the canister is measured, and water filled inside the canister loaded with spent nuclear fuel is drained to the outside through a drain port; a preliminary depressurization drying step (S200) of a canister in which, if the water drainage step (S100) inside the canister is completed, the drain port of the canister is kept closed until the pressure inside the canister reaches a preliminary drying pressure value of 100 Torr, and air inside the canister is exhausted through an exhaust port to primarily depressurize the interior of the canister; and a depressurization vaporization promotion step (S300) inside the canister in which, after the preliminary depressurization drying step (S200) of the canister is completed, the exhaust port of the canister is kept closed for a preset time so that moisture remaining inside the canister due to rapid depressurization can be filled into the inner space of the canister to promote depressurization vaporization without freezing; If the depressurization vaporization promotion step (S300) inside the canister is completed, a main depressurization drying step (S400) of the canister in which the air inside the canister is exhausted through the exhaust port of the canister until the pressure inside the canister reaches a preset main drying pressure value, thereby secondarily depressurizing the interior of the canister; if the main depressurization drying step (S400) of the canister is completed, an internal pressure measurement step (S500) of the canister in which the exhaust port and drain port of the canister are kept closed and the internal pressure of the canister is measured for 30 minutes; and a drying completion confirmation step (S600) of the canister in which, during the internal pressure measurement step (S500), it is checked whether the internal pressure of the canister is less than the reference depressurization drying pressure of 3 Torr, and if the internal pressure inside the canister is greater than or equal to the reference depressurization drying pressure, it is returned to the preliminary depressurization drying step (S200) of the canister;In the step of confirming the completion of drying of the canister (S600), if the pressure inside the canister is less than the reference reduced-pressure drying pressure of 3 Torr, a sealing step of the canister (S700) in which a non-reactive gas is injected into the canister so that the cladding of the spent nuclear fuel stored inside does not react with air and be damaged, and the canister is tightly sealed so that leakage does not occur during the transport and storage of the canister; and a radiation dose rate detection step (S800) in which a radiation dose rate detection means is operated to detect the radiation dose rate of the water drained through the canister's drain port and the exhausted air in real time while any one of the steps of the canister draining step (S100), the canister preliminary reduced-pressure drying step (S200), and the canister main reduced-pressure drying step (S400), or both steps, are being executed; A radiation dose rate verification step (S900) that checks whether the radiation dose rate for water and air detected in the radiation dose rate detection step (S800) is greater than or equal to a preset radiation dose rate, and if the detected radiation dose rate is less than the preset radiation dose rate, returns to the radiation dose rate detection step; a sample collection and radionuclide analysis step (S1000) that, in the radiation dose rate verification step (S900), if the detected radiation dose rate is greater than or equal to a preset radiation dose rate, collects a water sample or an air sample and performs radionuclide analysis on the collected water sample or air sample using a radionuclide analyzer; and a spent nuclear fuel cladding damage verification step (S1100) that checks whether an evidential radionuclide of spent nuclear fuel cladding damage has been detected in the sample collection and radionuclide analysis step (S1000), and if an evidential radionuclide has not been detected, returns to the radiation dose rate detection step;In a drying system for a canister loaded with spent nuclear fuel, comprising a step (S1100) for checking whether the spent nuclear fuel cladding is damaged, wherein if damage to the spent nuclear fuel cladding is confirmed, the execution of the step currently being executed among the draining step (S100) of the canister with confirmed damage to the spent nuclear fuel, the preliminary drying step (S200) of the canister, and the main drying step (S400) of the canister with confirmed damage to the spent nuclear fuel is stopped, and the canister with confirmed damage to the spent nuclear fuel cladding is returned to a temporary storage pool, the drying system comprises first to fifth connecting ports (20a to 20e) and a pressure gauge mounting hole (20f), and a distribution means for controlling the air flow path, An air distribution device (20) having a first connector (20a) that is detachably connected to the exhaust port (10a) of the canister (10) so as to be connected in communication with the inner hollow of the canister (10); first to fifth solenoid valves (EV1 to EV5) each mounted on the first to fifth connectors (20a to 20e) of the air distribution device (20) and opening and closing the first to fifth connectors (20a to 20e); a pressure sensing means (PG) mounted on the pressure gauge mounting hole (20f) of the air distribution device (20) to detect the internal pressure of the canister (10) and transmit the pressure sensing value; and a tank having an exhaust port in which non-reactive gas is stored, which is connected in communication with the second connector (20b) of the air distribution device (20) through a gas supply pipe (T1), and in the empty space where the water inside the canister (10) is drained, the non-reactive gas A non-reactive gas supply tank (30) that supplies and stops supplying non-reactive gas into a canister (10) through the air distribution device (20) according to the opening and closing operation of the second solenoid valve (EV2) so as to be filled;A radionuclide analysis device (40) equipped with a sample analysis chamber filled with collected samples and a radionuclide analysis unit for analyzing radionuclides among the samples within the sample analysis chamber, and for analyzing radionuclides in collected air and water samples discharged from the exhaust port (10a) and drain port (10b) of the canister (10); a primary pressure reduction exhaust pipe (T2) connected to communicate with the third connector (20c) of the air distribution device (20) and exhausting air within the canister (10) to the exhaust system; a sixth solenoid valve (EV6) mounted on the exhaust system-side end of the primary pressure reduction exhaust pipe (T2) and opening and closing the exhaust system-side end of the primary pressure reduction exhaust pipe (T2); and a first pressure reduction exhaust pipe (T2) mounted between the third and sixth solenoid valves (EV3) (EV6) and exhausting air within the canister (10) to the primary pressure A primary pressure reducing pump (PRP1) that pumps air to be exhausted into the exhaust system through an exhaust pipe (T2); a first radiation dose rate detection means (RD1) mounted on the primary pressure reducing exhaust pipe (T2) between the third solenoid valve (EV3) and the primary pressure reducing pump (PRP1), which detects the radiation dose rate of the air exhausted into the exhaust system along the primary pressure reducing exhaust pipe (T2) in real time and transmits the detected value; a first air sample collection pipe (AST1) that branches off to communicate with the primary pressure reducing exhaust pipe (T2) between the sixth solenoid valve (EV6) and the primary pressure reducing pump (PRP1), is connected to communicate with the inlet of the sample analysis chamber of the radionuclide analysis device (40), and supplies an air sample collected from the primary pressure reducing exhaust pipe (T2) into the sample analysis chamber of the radionuclide analysis device (40); and on the first air sample collection pipe (AST1). A seventh solenoid valve (EV7) that is mounted and opens and closes the first air sample collection tube (AST1); and a secondary pressure reduction exhaust pipe (T3) that is connected to communicate with the fourth connector (20d) of the air distribution device (20) and exhausts the air inside the canister (10) to the exhaust system;An eighth solenoid valve (EV8) mounted on the exhaust system-side end of the secondary pressure reducing exhaust pipe (T3) and opening and closing the exhaust system-side end of the secondary pressure reducing exhaust pipe (T3); a secondary pressure reducing pump (PRP2) mounted on the secondary pressure reducing exhaust pipe (T3) between the fourth and eighth solenoid valves (EV4) (EV8) and pumping air inside the canister (10) to be exhausted to the exhaust system through the secondary pressure reducing exhaust pipe (T3); a second radiation dose rate detection means (RD2) mounted on the secondary pressure reducing exhaust pipe (T3) between the fourth solenoid valve (EV4) and the secondary pressure reducing pump (PRP2) and detecting the radiation dose rate for the air exhausted to the exhaust system along the secondary pressure reducing exhaust pipe (T3) in real time and transmitting the detected value; and the between the eighth solenoid valve (EV8) and the secondary pressure reducing pump (PRP2) A second air sample collection tube (AST2) that branches off to communicate with the second depressurization exhaust pipe (T3), is connected to communicate with the inlet of the sample analysis chamber of the radionuclide analysis device (40), and supplies an air sample collected from the second depressurization exhaust pipe (T3) into the sample analysis chamber of the radionuclide analysis device (40); a ninth solenoid valve (EV9) mounted on the second air sample collection tube (AST2) and opens and closes the second air sample collection tube (AST2); a drain pipe (T4) that is detachably connected to the drain port (10b) of the canister (10) and drains water filled in the canister (10) into a drainage system; tenth and eleventh solenoid valves (EV10) (EV11) each mounted on both ends of the drain pipe (T4) and each open and close both ends of the drain pipe (T4); and the tenth and eleven A drainage pump (DP) mounted on the drain pipe (T4) between the solenoid valves (EV10) and (EV11) and pumping and draining the water filled in the canister (10); and a third radiation dose rate detection means (RD3) mounted on the drain pipe (T4) between the first solenoid valve (EV10) and the drainage pump (DP), detecting the radiation dose rate of the water drained along the drain pipe (T4) in real time and transmitting the detected value;A water sample collection tube (WST1) that branches off to communicate with the drain pipe (T4) between the 11th solenoid valve (EV11) and the drain pump (DP), is connected to communicate with the inlet of the sample analysis chamber of the radionuclide analysis device (40), and supplies a water sample collected from the drain pipe (T4) into the sample analysis chamber of the radionuclide analysis device (40); a 12th solenoid valve (EV12) mounted on the water sample collection tube (WST1) and opening and closing the water sample collection tube (WST1); a wash water supply tank (50) having a drain port in which wash water is stored, which supplies wash water into the 1st and 2nd depressurization exhaust pipes (T2) (T3) and the drain pipe (T4) for washing; and a wash water supply tank (50) that branches off to communicate with the drain pipe (T4) between the 10th solenoid valve (EV10) and the 3rd radiation dose rate detection means (RD3), and the wash water supply tank (50). A first washing water supply pipe (WWT1) connected to communicate with a drain and supplying washing water into the drain pipe (T4); a 13th solenoid valve (EV13) mounted on the first washing water supply pipe (WWT1) and opening and closing the first washing water supply pipe (WWT1); a washing water supply pump (WWP) mounted on the first washing water supply pipe (WWT1) between the washing water supply tank (50) and the 13th solenoid valve (EV13) and pumping washing water within the washing water supply tank (50); a second washing water supply pipe (WWT2) branched from the first washing water supply pipe (WWT1) between the washing water supply pump (WWP) and the 13th solenoid valve (EV13) and connected to communicate with the 5th connector (20e) of the air distribution device (20) and supplying washing water into the primary and secondary pressure reduction exhaust pipes (T2) (T3);A control unit (60) that is respectively connected to the pressure sensing means (PG), first to third radiation dose rate detection means (RD1 to RD3), radionuclide analysis device (40), primary and secondary pressure reducing pumps (PRP1) (PRP2), drainage pump (DP), wash water supply pump (WWP), and first to thirteenth solenoid valves (EV1 to EV13), and controls the operation of the primary and secondary pressure reducing pumps (PRP1) (PRP2), drainage pump (DP), wash water supply pump (WWP), and first to thirteenth solenoid valves (EV1 to EV13) based on data received from the pressure sensing means (PG), first to third radiation dose rate detection means (RD1 to RD3), and radionuclide analysis device (30) and received operation commands; and a display unit that displays received information, an input unit that inputs commands from an operator, and an operation status display unit that outputs the operation status of the system visually and audibly, and the control unit (60) and A drying system for a canister loaded with spent nuclear fuel, characterized by comprising a control panel (70) that displays various information transmitted from the control unit (60) on a display unit, outputs normal, abnormal, and emergency statuses during system operation to an operation status display unit, and transmits an operator's operation command to the control unit (60) through an input unit. Claim 2 A drainage step (S100) of a canister in which the internal pressure of the canister is measured, and water filled inside the canister loaded with spent nuclear fuel is drained to the outside through a drain port; a preliminary depressurization drying step (S200) of a canister in which, if the water drainage step (S100) inside the canister is completed, the drain port of the canister is kept closed until the pressure inside the canister reaches a preliminary drying pressure value of 100 Torr, and air inside the canister is exhausted through an exhaust port to primarily depressurize the interior of the canister; and a depressurization vaporization promotion step (S300) inside the canister in which, after the preliminary depressurization drying step (S200) of the canister is completed, the exhaust port of the canister is kept closed for a preset time so that moisture remaining inside the canister due to rapid depressurization can be filled into the inner space of the canister to promote depressurization vaporization without freezing; If the depressurization vaporization promotion step (S300) inside the canister is completed, a main depressurization drying step (S400) of the canister in which the air inside the canister is exhausted through the exhaust port of the canister until the pressure inside the canister reaches a preset main drying pressure value, thereby secondarily depressurizing the interior of the canister; if the main depressurization drying step (S400) of the canister is completed, an internal pressure measurement step (S500) of the canister in which the exhaust port and drain port of the canister are kept closed and the internal pressure of the canister is measured for 30 minutes; and a drying completion confirmation step (S600) of the canister in which, during the internal pressure measurement step (S500), it is checked whether the internal pressure of the canister is less than the reference depressurization drying pressure of 3 Torr, and if the internal pressure inside the canister is greater than or equal to the reference depressurization drying pressure, it is returned to the preliminary depressurization drying step (S200) of the canister;In the step of confirming the completion of drying of the canister (S600), if the pressure inside the canister is less than the reference reduced-pressure drying pressure of 3 Torr, a sealing step of the canister (S700) in which a non-reactive gas is injected into the canister so that the cladding of the spent nuclear fuel stored inside does not react with air and be damaged, and the canister is tightly sealed so that leakage does not occur during the transport and storage of the canister; and a radiation dose rate detection step (S800) in which a radiation dose rate detection means is operated to detect the radiation dose rate of the water drained through the canister's drain port and the exhausted air in real time while any one of the steps of the canister draining step (S100), the canister preliminary reduced-pressure drying step (S200), and the canister main reduced-pressure drying step (S400), or both steps, are being executed; A radiation dose rate verification step (S900) that checks whether the radiation dose rate for water and air detected in the radiation dose rate detection step (S800) is greater than or equal to a preset radiation dose rate, and if the detected radiation dose rate is less than the preset radiation dose rate, returns to the radiation dose rate detection step; a sample collection and radionuclide analysis step (S1000) that, in the radiation dose rate verification step (S900), if the detected radiation dose rate is greater than or equal to a preset radiation dose rate, collects a water sample or an air sample and performs radionuclide analysis on the collected water sample or air sample using a radionuclide analyzer; and a spent nuclear fuel cladding damage verification step (S1100) that checks whether an evidential radionuclide of spent nuclear fuel cladding damage has been detected in the sample collection and radionuclide analysis step (S1000), and if an evidential radionuclide has not been detected, returns to the radiation dose rate detection step;In a drying system for a canister loaded with spent nuclear fuel, comprising a step (S1100) for checking whether the spent nuclear fuel cladding is damaged, wherein if damage to the spent nuclear fuel cladding is confirmed, the execution of the step currently being executed among the draining step (S100) of the canister with confirmed damage to the spent nuclear fuel, the preliminary drying step (S200) of the canister, and the main drying step (S400) of the canister with confirmed damage to the spent nuclear fuel is stopped, and the canister with confirmed damage to the spent nuclear fuel cladding is returned to a temporary storage pool, the drying system comprises first to fifth connecting ports (20a to 20e) and a pressure gauge mounting hole (20f), and a distribution means for controlling the air flow path, An air distribution device (20) having a first connector (20a) that is detachably connected to a drain port (10b) of a canister (10) so as to be connected to an inner hollow of the canister (10); first to fifth solenoid valves (EV1 to EV5) each mounted on the first to fifth connectors (20a to 20e) of the air distribution device (20) and opening and closing the first to fifth connectors (20a to 20e); a pressure sensing means (PG) mounted on a pressure gauge mounting hole (20f) of the air distribution device (20) to detect the internal pressure of the canister (10) and transmit the pressure sensing value; and a tank having an exhaust port in which non-reactive gas is stored, which is connected to the exhaust port (10a) of the canister (10) through a gas supply pipe (T1) so as to be connected to the canister (10), and the non-reactive gas is filled into the empty space where water in the canister (10) has been drained. A non-reactive gas supply tank (30) that supplies and stops supplying non-reactive gas into a canister (10) through an air distribution device (20) according to the opening and closing operation of the second solenoid valve (EV2); and a 13th solenoid valve (EV13) mounted on the gas supply pipe (T1) and opening and closing the gas supply pipe (T1);A sample analysis chamber filled with collected samples and a radionuclide analysis unit for analyzing radionuclides among the samples within the sample analysis chamber, and a radionuclide analysis device (40) for analyzing radionuclides in collected air and water samples discharged from the drain port (10b) of the canister (10); a drain pipe (T4) connected to communicate with the third connector (20c) of the air distribution device (20) and draining water within the canister (10) into a drainage system; an eleventh solenoid valve (EV11) mounted on the drain pipe (T4) and opening and closing the drain pipe (T4); and a third solenoid valve (EV3) mounted on the drain pipe (T4) between the eleventh solenoid valve (EV11) and the third connector (20c) of the air distribution device (20), and allowing water filled in the canister (10) to be discharged through the drain port (10b) and drained into the drainage system along the drain pipe (T4). A drainage pump (DP) for pumping; a third radiation dose rate detection means (RD3) mounted on a drain pipe (T4) between the drainage pump (DP) and a third solenoid valve (EV3), which detects the radioactivity rate of water drained along the drain pipe (T4) in real time and transmits the detected value; a water sample collection tube (WST) branched out to communicate from the drain pipe (T4) between the drainage pump (DP) and the eleventh solenoid valve (EV11), connected to communicate with the inlet of the sample analysis chamber of the radionuclide analysis device (40), and supplies a water sample collected from the drain pipe (T4) into the sample analysis chamber of the radionuclide analysis device (40); a thirteenth solenoid valve (EV13) mounted on the water sample collection tube (WST) and opening and closing the water sample collection tube (WST); and a canister (10) connected to communicate with the fourth connector (20d) of the air distribution device (20). A primary pressure reducing exhaust pipe (T2) for exhausting internal air into an exhaust system; and a sixth solenoid valve (EV6) mounted on the primary pressure reducing exhaust pipe (T2) and opening and closing the primary pressure reducing exhaust pipe (T2);A primary pressure reducing pump (PRP1) mounted on the primary pressure reducing exhaust pipe (T2) between the sixth solenoid valve (EV6) and the fourth solenoid valve (EV4) of the fourth connector (20d) of the air distribution device (20), and pumping air inside the canister (10) to be exhausted to the exhaust system through the primary pressure reducing exhaust pipe (T2); a first radiation dose rate detection means (RD1) mounted on the primary pressure reducing exhaust pipe (T2) between the fourth solenoid valve (EV4) of the fourth connector (20d) of the air distribution device (20) and the primary pressure reducing pump (PRP1), detecting the radiation dose rate of the air exhausted to the exhaust system along the primary pressure reducing exhaust pipe (T2) in real time and transmitting the detected value; and branched to communicate with the primary pressure reducing exhaust pipe (T2) between the primary pressure reducing pump (PRP1) and the sixth solenoid valve (EV6), and A first air sample collection tube (AST1) connected to communicate with the inlet of the sample analysis chamber of the radionuclide analysis device (40) and supplying an air sample collected from the first depressurization exhaust pipe (T2) into the sample analysis chamber of the radionuclide analysis device (40); a seventh solenoid valve (EV7) mounted on the first air sample collection tube (AST1) and opening and closing the first air sample collection tube (AST1); a second depressurization exhaust pipe (T3) connected to communicate with the fifth connector (20e) of the air distribution device (20) and exhausting air inside the canister (10) into the exhaust system; an eighth solenoid valve (EV8) mounted on the second depressurization exhaust pipe (T3) and opening and closing the second depressurization exhaust pipe (T3); and between the eighth solenoid valve (EV8) and the fifth solenoid valve (EV5) of the fifth connector (20e) of the air distribution device (20). A secondary pressure reducing pump (PRP2) mounted on a secondary pressure reducing exhaust pipe (T3) and pumping air inside a canister (10) to be exhausted to the exhaust system through the secondary pressure reducing exhaust pipe (T3);A second radiation dose rate detection means (RD2) mounted on the secondary pressure reduction exhaust pipe (T3) between the fifth solenoid valve (EV5) of the fifth connector (20e) of the air distribution device (20) and the secondary pressure reduction pump (PRP2), which detects the radiation dose rate of the air exhausted into the exhaust system along the secondary pressure reduction exhaust pipe (T3) in real time and transmits the detected value; a second air sample collection pipe (AST2) branched to communicate with the secondary pressure reduction exhaust pipe (T3) between the secondary pressure reduction pump (PRP2) and the eighth solenoid valve (EV8), connected to communicate with the inlet of the sample analysis chamber of the radionuclide analysis device (40), and supplies an air sample collected from the secondary pressure reduction exhaust pipe (T3) into the sample analysis chamber of the radionuclide analysis device (40); and mounted on the second air sample collection pipe (AST2), and the second air sample collection pipe (AST2) A ninth solenoid valve (EV9) that opens and closes; a washing water supply tank (50) having a drain port in which washing water is stored, which is connected to the second connector (20b) of the air distribution device (20) and the washing water supply pipe (WWT) in communication, and which supplies washing water into the drain pipe (T4) and the primary and secondary pressure reduction exhaust pipes (T2) (T3) for washing by the opening and closing operation of the second solenoid valve (EV2); and a washing water supply pump (WWP) mounted on the washing water supply pipe (WWT) between the second solenoid valve (EV2) and the washing water supply tank (50), which pumps washing water within the washing water supply tank (50);A control unit (60) that controls the operation of the primary and secondary pressure reduction pumps (PRP1)(PRP2), drainage pump (DP), wash water supply pump (WWP), first to ninth solenoid valves (EV1 to EV9), and eleventh to eleventh solenoid valves (EV11 to EV13) respectively, based on data received from the pressure sensing means (PG), first to third radiation dose rate detection means (RD1 to RD3), and radionuclide analysis device (40) and received operation commands; a display unit that displays received information, and inputs commands from an operator A drying system for a canister loaded with spent nuclear fuel, characterized by comprising an input unit, an operation status display unit that outputs the system's operation status visually and audibly, a control panel (70) connected to the control unit (60) that displays various information transmitted from the control unit (60) on a display unit, outputs normal, abnormal, and emergency statuses during system operation to the operation status display unit, and transmits an operator's operation command through the input unit to the control unit (60). Claim 3 A drainage step (S100) of a canister in which the internal pressure of the canister is measured, and water filled inside the canister loaded with spent nuclear fuel is drained to the outside through a drain port; a preliminary depressurization drying step (S200) of a canister in which, if the water drainage step (S100) inside the canister is completed, the drain port of the canister is kept closed until the pressure inside the canister reaches a preliminary drying pressure value of 100 Torr, and air inside the canister is exhausted through an exhaust port to primarily depressurize the interior of the canister; and a depressurization vaporization promotion step (S300) inside the canister in which, after the preliminary depressurization drying step (S200) of the canister is completed, the exhaust port of the canister is kept closed for a preset time so that moisture remaining inside the canister due to rapid depressurization can be filled into the inner space of the canister to promote depressurization vaporization without freezing; If the depressurization vaporization promotion step (S300) inside the canister is completed, a main depressurization drying step (S400) of the canister in which the air inside the canister is exhausted through the exhaust port of the canister until the pressure inside the canister reaches a preset main drying pressure value, thereby secondarily depressurizing the interior of the canister; if the main depressurization drying step (S400) of the canister is completed, an internal pressure measurement step (S500) of the canister in which the exhaust port and drain port of the canister are kept closed and the internal pressure of the canister is measured for 30 minutes; and a drying completion confirmation step (S600) of the canister in which, during the internal pressure measurement step (S500), it is checked whether the internal pressure of the canister is less than the reference depressurization drying pressure of 3 Torr, and if the internal pressure inside the canister is greater than or equal to the reference depressurization drying pressure, it is returned to the preliminary depressurization drying step (S200) of the canister;In the step of confirming the completion of drying of the canister (S600), if the pressure inside the canister is less than the reference reduced-pressure drying pressure of 3 Torr, a sealing step of the canister (S700) in which a non-reactive gas is injected into the canister so that the cladding of the spent nuclear fuel stored inside does not react with air and be damaged, and the canister is tightly sealed so that leakage does not occur during the transport and storage of the canister; and a radiation dose rate detection step (S800) in which a radiation dose rate detection means is operated to detect the radiation dose rate of the water drained through the canister's drain port and the exhausted air in real time while any one of the steps of the canister draining step (S100), the canister preliminary reduced-pressure drying step (S200), and the canister main reduced-pressure drying step (S400), or both steps, are being executed; A radiation dose rate verification step (S900) that checks whether the radiation dose rate for water and air detected in the radiation dose rate detection step (S800) is greater than or equal to a preset radiation dose rate, and if the detected radiation dose rate is less than the preset radiation dose rate, returns to the radiation dose rate detection step; a sample collection and radionuclide analysis step (S1000) that, in the radiation dose rate verification step (S900), if the detected radiation dose rate is greater than or equal to a preset radiation dose rate, collects a water sample or an air sample and performs radionuclide analysis on the collected water sample or air sample using a radionuclide analyzer; and a spent nuclear fuel cladding damage verification step (S1100) that checks whether an evidential radionuclide of spent nuclear fuel cladding damage has been detected in the sample collection and radionuclide analysis step (S1000), and if an evidential radionuclide has not been detected, returns to the radiation dose rate detection step;In a drying system for a canister loaded with spent nuclear fuel, comprising a step (S1100) for checking whether the spent nuclear fuel cladding is damaged, and if damage to the spent nuclear fuel cladding is confirmed, stopping the execution of the step currently being executed among the draining step (S100) of the canister where damage to the spent nuclear fuel cladding is confirmed, the preliminary drying step (S200) of the canister, and the main drying step (S400) of the canister where damage to the spent nuclear fuel cladding is confirmed, and a drying system for a canister where damage to the spent nuclear fuel cladding is confirmed, wherein the drying system is a tank having an exhaust port where non-reactive gas is stored, and is connected to the exhaust port (10a) of the canister (10) through a gas supply pipe (T1). A non-reactive gas supply tank (30) that supplies non-reactive gas into a canister (10) so that the water inside the canister (10) is drained and the non-reactive gas is filled into the empty space; a pressure sensing means (PG) mounted on the gas supply pipe (T1) and detecting the internal pressure of the canister (10) and transmitting the detected pressure value; a 13th solenoid valve (EV13) mounted on the gas supply pipe (T1) between the pressure sensing means (PG) and the non-reactive gas supply tank (20) and opening and closing the gas supply pipe (T1); a drain pipe (T4) that is detachably connected to the drain port (10b) of the canister (10) and drains the water filled inside the canister (10) into a drainage system; and 10th and 11th, each mounted on the ends of the drain pipe (T4) and each opening and closing the ends of the drain pipe (T4). A solenoid valve (EV10)(EV11); a drainage pump (DP) mounted on a drain pipe (T4) between the 10th and 11th solenoid valves (EV10)(EV11) and pumping and draining water filled in the canister (10); and a washing water supply tank (50) having a drain port in which washing water is stored, which supplies washing water into a flow path of water and air discharged through the drain port (10b) of the canister (10) to wash;A washing water supply pipe (WWT) that is branched out to communicate from the drain pipe (T4) between the 10th and 11th solenoid valves (EV10) (EV11) and connected to communicate with the drain of the washing water supply tank (50) to supply washing water into the drain pipe (T4); a second solenoid valve (EV2) mounted on the washing water supply pipe (WWT) and opening and closing the washing water supply pipe (WWT); a washing water supply pump (WWP) mounted on the washing water supply pipe (WWT) between the second solenoid valve (EV2) and the drain of the washing water supply tank (50) and pumping washing water within the washing water supply tank (50) so that washing water is supplied along the washing water supply pipe (WWT); and a sample analysis chamber filled with collected samples and a radionuclide analysis unit that analyzes radionuclides among the samples within the sample analysis chamber, and water discharged from the drain (10b) of the canister (10) and water collected from the air and A radionuclide analyzer (40) for analyzing radionuclides in an air sample; a water sample collection tube (WST) that branches off from the drain pipe (T4) between the 11th solenoid valve (EV11) and the drain pump (DP), is connected to the inlet of the sample analysis chamber of the radionuclide analyzer (40), and supplies a water sample collected from the drain pipe (T4) into the sample analysis chamber of the radionuclide analyzer (40); a 12th solenoid valve (EV12) mounted on the water sample collection tube (WST) and opens and closes the water sample collection tube (WST); a primary pressure reduction exhaust pipe (T2) that branches off from the drain pipe (T4) between the branch point with the wash water supply pipe (WWT) and the drain pump (DP), and exhausts air discharged along the drain pipe (T4) into an exhaust system; and a primary pressure reduction exhaust pipe (T2) mounted on the primary pressure reduction exhaust pipe (T2) and the primary pressure A sixth solenoid valve (EV6) for opening and closing the exhaust pipe (T2); a first pressure reducing pump (PRP1) mounted on the first pressure reducing exhaust pipe (T2) between the branch point with the drain pipe (T4) and the sixth solenoid valve (EV6), and pumping air inside the canister (10) to be exhausted into the exhaust system through the drain pipe (T4) and the first pressure reducing exhaust pipe (T2);A first air sample collection tube (AST1) branched from the first pressure reduction exhaust pipe (T2) between the sixth solenoid valve (EV6) and the first pressure reduction pump (PRP1) and connected to communicate with the sample analysis chamber of the radionuclide analysis device (40), and supplying an air sample collected from the first pressure reduction exhaust pipe (T2) into the sample analysis chamber of the radionuclide analysis device (40); a seventh solenoid valve (EV7) mounted on the first air sample collection tube (AST1) and opening and closing the first air sample collection tube (AST1); a second pressure reduction exhaust pipe (T3) branched to communicate with the drain pipe (T4) between the branch point of the wash water supply pipe (WWT) and the branch point of the first pressure reduction exhaust pipe (T2), and exhausting the air discharged along the drain pipe (T4) into the exhaust system; and a second pressure reduction exhaust pipe (T3) mounted on the second pressure reduction exhaust pipe (T3) and the second pressure An eighth solenoid valve (EV8) for opening and closing the exhaust pipe (T3); a secondary pressure reduction pump (PRP2) mounted on the secondary pressure reduction exhaust pipe (T3) between the branch point with the drain pipe (T4) and the eighth solenoid valve (EV8), and pumping air inside the canister (10) to be exhausted into the exhaust system through the drain pipe (T4) and the secondary pressure reduction exhaust pipe (T3); a second air sample collection pipe (AST2) branched from the secondary pressure reduction exhaust pipe (T3) between the eighth solenoid valve (EV8) and the secondary pressure reduction pump (PRP2), connected to communicate with the sample analysis chamber of the radionuclide analysis device (40), and supplying an air sample collected from the secondary pressure reduction exhaust pipe (T3) into the sample analysis chamber of the radionuclide analysis device (40); and a device mounted on the second air sample collection pipe (AST2) and for opening and closing the second air sample collection pipe (AST2). A ninth solenoid valve (EV9); and a radiation dose rate detection means (RD) mounted on a drain pipe (T4) between the branch point with the wash water supply pipe (WWT) and the branch point with the secondary pressure reduction exhaust pipe (T3), which detects the radiation dose rate of water and air discharged along the drain pipe (T4) through the drain pipe (10b) of the canister (10) in real time and transmits the detected value;The above pressure sensing means (PG), radiation dose rate detection means (RD), radionuclide analyzer (40), drainage pump (DP), wash water supply pump (WWP), primary and secondary pressure reduction pumps (PRP1) (PRP2), and second, sixth to ninth, tenth, eleventh, and thirteenth solenoid valves (EV2) (EV6 to EV9) (EV10) (EV11) (EV13) are each connected to the above pressure sensing means (PG), radiation dose rate detection means (RD), and radionuclide analyzer (40), and the operation of the drainage pump (DP), wash water supply pump (WWP), primary and secondary pressure reduction pumps (PRP1) (PRP2), and second, sixth to ninth, tenth, eleventh, and thirteenth solenoid valves (EV2) (EV6 to EV9) (EV10) (EV11) (EV13) is each controlled based on data received from the above pressure sensing means (PG), radiation dose rate detection means (RD), and radionuclide analyzer (40) and operation commands received. A drying system for a canister loaded with spent nuclear fuel, characterized by comprising: a control unit (60); a display unit for displaying received information; an input unit for inputting a worker's command; and an operation status display unit for outputting the system's operation status visually and audibly; a control panel (70) connected to the control unit (60) for displaying various information transmitted from the control unit (60) on the display unit, outputting normal, abnormal, and emergency statuses during system operation to the operation status display unit, and transmitting a worker's operation command through the input unit to the control unit (60). Claim 4 A drying system for a canister loaded with spent nuclear fuel, wherein, in any one of claims 1, 2, or 3, the drying system is further characterized by including a filter residue detection means (FRD) that is respectively mounted on a primary pressurized exhaust pipe (T2) between the 6th solenoid valve (EV6) and the exhaust system, a secondary depressurized exhaust pipe (T3) between the 8th solenoid valve (EV8) and the exhaust system, and a drain pipe (T4) between the 11th solenoid valve (EV11) and the drainage system, so as to be connected to a control unit (60), and simultaneously filters filter residues in the air exhausted to the exhaust system through the primary and secondary pressurized exhaust pipes (T2) (T3) and filter residues in the water drained to the drainage system through the drain pipe (T4), and simultaneously monitors the presence of residual material on the filter by taking and acquiring an image of the residual material on the filter and transmitting the acquired image to the control unit (60). Claim 5 In claim 4, the filter residue detection means (FRD) is characterized by comprising: a housing (F1) having connecting portions at both ends and having a hollow interior; a filter material (F2) embedded within the housing (F1) for filtering air; a camera means (F3) embedded within the housing (F1) connected to a control unit (60) to photograph the front surface of the filter material (F2) and transmitting the photographed image; and a lamp means (F4) embedded within the housing (F1) connected to a control unit (60) to illuminate the front surface of the filter material (F2). Claim 6 In any one of claims 1, 2, or 3, the radionuclide analysis device (40) comprises: a sample analysis chamber (41) having a transparent tube shape having an internal hollow, having two inlets (41a) (41b) formed on the upper surface for receiving a water sample or an air sample in the internal hollow, two outlets (41c) (41d) formed on the lower part for discharging the water sample or an air sample received in the internal hollow to the outside, and a solid scintillator layer (41e) which is mounted in close contact on the inner surface and emits fine visible light by colliding with radiation emitted as a radioactive nuclide contained in the water or air sample filled in the internal hollow decays; and a control unit (60) mounted on the end side of the sample analysis chamber (41) to be connected to the sample analysis chamber (41), detecting the water level inside the sample analysis chamber (41), and transmitting the detection signal. A water level sensing means (42); a pressure sensing means (43) mounted on the sample analysis chamber (41) to be connected to the control unit (60), which senses the pressure within the sample analysis chamber (41) and transmits the pressure signal; an inlet solenoid valve (IV1) (IV2) mounted on each of the two inlets (41a) (41b) of the sample analysis chamber (41) to be connected to the control unit (60) and which opens and closes the two inlets (41a) (41b) respectively; an outlet solenoid valve (OV1) (OV2) mounted on each of the two outlets (41c) (41d) of the sample analysis chamber (41) to be connected to the control unit (60) and which opens and closes the two outlets (41c) (41d) respectively; and a device mounted in close contact on the opposite outer surface of the sample analysis chamber (41) to be connected to the control unit (60), and A drying system for a canister loaded with spent nuclear fuel, characterized by comprising a plurality of optical sensors that detect visible light emitted from a solid scintillator layer (41e) and transmit the detection signal, and a radionuclide analysis unit (44) that analyzes radionuclides based on the visible light detection signal transmitted from the optical sensors and transmits the radionuclide analysis data to a control unit (60).

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