Multi-functional Bench for Spent Fuel Storage and Transportation Containers and Its Working Method

Abstract

The present invention discloses a multi-functional bench for spent fuel storage and transportation containers and its working method. The multi-functional bench for spent fuel storage and transportation containers includes a bench main body and a discharging and cooling device. The bench main body includes a frame, a gas-water separator, a high-efficiency filter, an exhaust fan, a cooler, connecting pipelines and interface components arranged in the frame. The discharging and cooling device includes a shielding filter arranged outside the frame. The multi-functional bench for spent fuel storage and transportation containers of the present invention integrates the gas-water separator, the high-efficiency filter, the exhaust fan, the cooler, the connecting pipelines and each interface in a frame, and cooperates with the shielding filter outside the frame. Through the connecting pipelines, the connection between each device and interface is realized, and functions such as water filling and air exhausting, air filling and water discharging, and discharging and cooling of the spent fuel storage and transportation containers are achieved.

Description

Technical Field

[0001] The present invention relates to an auxiliary device for spent fuel transportation containers, and particularly to a multi-functional gantry for spent fuel storage and transportation containers and its working method. Background Art

[0002] Nuclear fuel that has been in operation in a nuclear reactor for a period of time is called spent fuel. Spent fuel has a high radiation level and decay heat, and requires special transportation containers for transfer and transportation. The loading and unloading operations of spent fuel transportation containers are complex. To improve work efficiency and reliability, it is necessary to develop a multi-functional gantry that can complete operations such as water filling and exhaust, gas filling and drainage, and unloading and cooling of spent fuel transportation containers. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a multi-functional gantry for spent fuel storage and transportation containers and its working method.

[0004] The technical solution adopted by the present invention to solve its technical problems is: to provide a multi-functional gantry for spent fuel storage and transportation containers, including a gantry main body and a unloading and cooling device. The gantry main body includes a frame, a gas-water separator, a high-efficiency filter, an exhaust fan, a cooler, connecting pipelines, and an interface assembly arranged inside the frame. The unloading and cooling device includes a shielding filter arranged outside the frame.

[0005] The interface assembly includes a water inlet interface for connecting a submersible pump, a drainage interface, an inlet and drainage interface and an inlet and exhaust interface for connecting a spent fuel storage and transportation container respectively, and an air inlet interface for connecting a gas source.

[0006] The connecting pipelines include a first pipeline, a second pipeline, a third pipeline, an exhaust pipeline, and a drainage pipeline.

[0007] One end of the first pipeline is connected to the inlet and drainage interface, and the other end is connected to the water inlet interface through a first three-way valve. A humidity sensor and a first liquid level switch are arranged on the first pipeline.

[0008] One end of the second pipeline is connected to the inlet and exhaust interface, and the other end is connected to the inlet of the gas-water separator. A second liquid level switch is arranged on the second pipeline. The air inlet interface is connected to the second pipeline through a second three-way valve.

[0009] The exhaust pipeline is connected between the air outlet of the gas-water separator and the exhaust fan, and the high-efficiency filter is arranged on the exhaust pipeline. One end of the drainage pipeline is connected to the first three-way valve, and the other end is connected to the drainage interface and the inlet of the gas-water separator through a third three-way valve.

[0010] The shell side of the cooler is connected to the first pipeline; one end of the third pipeline is connected to the air inlet and outlet interface, and the other end is connected to the inlet of the shielding filter through a fourth three-way valve. The tube side of the cooler is connected between the outlet of the shielding filter and the second pipeline; a pressure gauge and a temperature sensor are provided on the third pipeline.

[0011] Preferably, a humidity sensor and a first liquid level switch are provided on the first pipeline.

[0012] Preferably, a second liquid level switch is provided on the second pipeline.

[0013] Preferably, a pressure gauge and a temperature sensor are provided on the third pipeline.

[0014] Preferably, a flow meter is provided on the drain pipeline.

[0015] Preferably, a drain pipe is provided at the drain outlet of the gas-liquid separator for connection to the canning well.

[0016] Preferably, the first three-way valve to the fourth three-way valve are respectively electric three-way ball valves.

[0017] Preferably, the unloading and cooling device further includes a housing with a radiation shielding function, and the shielding filter is arranged inside the housing.

[0018] Preferably, the bench body further includes side plates arranged on each side surface of the frame; the side plates on at least one side surface are openable and closable.

[0019] Preferably, the bench body further includes an electrical cabinet installed inside the frame;

[0020] The electrical cabinet is respectively connected to the humidity sensor and the temperature sensor to collect and process the data detected by the humidity sensor and the temperature sensor.

[0021] Preferably, a lifting ring is provided at the top of the frame.

[0022] Preferably, universal wheels with braking devices are provided at the bottom of the frame.

[0023] Preferably, a handle is provided on at least one side surface of the frame.

[0024] Preferably, the bench body further includes a vacuum pumping device arranged inside the frame, a first interface and a second interface respectively used for connecting to the spent fuel storage and transportation container; the vacuum pumping device includes a vacuum pumping pipeline, a vacuum pump and a vacuum gauge;

[0025] One end of the vacuum pipeline is respectively connected to the first interface and the second interface, and the other end is connected to the vacuum pump. The vacuum gauge is arranged on the vacuum pipeline; the outlet of the vacuum pump is connected to the inlet of the high-efficiency filter.

[0026] The present invention also provides a working method for a multi-functional bench of a spent fuel storage and transportation container, including filling water and exhausting air, inflating and draining water, and unloading and cooling for the spent fuel storage and transportation container.

[0027] Preferably, filling water and exhausting air for the spent fuel storage and transportation container includes the following steps:

[0028] S1.1. Connect the submersible pump to the water inlet interface, place the submersible pump into the canning well, connect the first three-way valve to the water inlet interface and the first pipeline, and connect the water inlet and outlet interface and the air inlet and outlet interface to the spent fuel storage and transportation container respectively.

[0029] S1.2. Start the submersible pump, the submersible pump pumps water from the canning well, and the water flow sequentially passes through the submersible pump, the water inlet interface, the first pipeline and the water inlet and outlet interface and enters the spent fuel storage and transportation container.

[0030] S1.3. The gas discharged from the spent fuel storage and transportation container enters the second pipeline through the air inlet and outlet interface, sequentially passes through the second three-way valve and the second liquid level switch and enters the gas-water separator. After removing the moisture, it enters the plant ventilation system along the exhaust pipeline through the high-efficiency filter and the exhaust fan.

[0031] S1.4. After the spent fuel storage and transportation container is filled with water, the water overflows from the air inlet and outlet interface and triggers the second liquid level switch, and the submersible pump stops pumping water.

[0032] Preferably, inflating and draining water for the spent fuel storage and transportation container includes the following steps:

[0033] S2.1. Connect the first three-way valve to the first pipeline and the drainage pipeline, connect the drainage interface to the canning well, and connect the third three-way valve to the drainage interface and the drainage pipeline; connect the air inlet interface to the gas source; connect the second three-way valve to the air inlet interface and the air inlet and outlet interface, and connect the water inlet and outlet interface and the air inlet and outlet interface to the spent fuel storage and transportation container respectively.

[0034] S2.2. Start the gas source, and the compressed air enters the spent fuel storage and transportation container through the air inlet interface, the second pipeline and the air inlet and outlet interface; the gas pressure presses the water in the spent fuel storage and transportation container out from the water inlet and outlet interface, and enters the canning well along the first pipeline, the drainage pipeline and the drainage interface.

[0035] S2.3. When the first liquid level switch on the first pipeline detects that there is no water flow, the third three-way valve connects the drainage pipeline and the gas-water separator; start the exhaust fan, and the gas pressure presses the gas in the spent fuel storage and transportation container out and discharges it into the gas-water separator, and then the gas enters the plant ventilation system along the exhaust pipeline through the high-efficiency filter and the exhaust fan;

[0036] S2.4. After the humidity detected by the humidity sensor on the first pipeline reaches the humidity set value, the gas source stops supplying gas.

[0037] Preferably, the unloading and cooling of the spent fuel storage and transportation container includes the following steps:

[0038] S3.1. Water filling and exhaust cooling;

[0039] S3.1.1. Connect the submersible pump to the water inlet interface and place the submersible pump into the canning well. The first three-way valve connects the water inlet interface and the first pipeline, the third three-way valve connects the drainage pipeline and the gas-water separator, the fourth three-way valve connects the shielding filter and the third pipeline, and the water inlet and drainage interface and the air inlet and exhaust interface are respectively connected to the spent fuel storage and transportation container;

[0040] S3.1.2. The submersible pump pumps water from the canning well, and the water flow flows along the first pipeline, passes through the shell side of the cooler and then enters the spent fuel storage and transportation container through the water inlet and drainage interface;

[0041] S3.1.3. The gas in the spent fuel storage and transportation container is discharged from the air inlet and exhaust interface into the third pipeline, and then enters the second pipeline along the third pipeline successively through the shielding filter and the tube side of the cooler, flows along the second pipeline into the gas-water separator, and then is discharged into the plant ventilation system along the exhaust pipeline through the high-efficiency filter and the exhaust fan;

[0042] S3.2. Hot water replacement cooling;

[0043] S3.2.1. After the spent fuel storage and transportation container is filled with water, the water overflows from the air inlet and exhaust interface to trigger the second liquid level switch, and the submersible pump stops pumping water;

[0044] S3.2.2. The fourth three-way valve connects the third pipeline and the canning well. After the submersible pump starts, it pumps water from the canning well. The water flow flows along the first pipeline, passes through the shell side of the cooler and then enters the spent fuel storage and transportation container through the water inlet and drainage interface; the water in the spent fuel storage and transportation container is discharged from the air inlet and exhaust interface, and is discharged to the canning well along the third pipeline through the fourth three-way valve;

[0045] S3.2.3. After the temperature detected by the temperature sensor on the third pipeline is less than or equal to the temperature set value, the submersible pump stops pumping water.

[0046] Preferably, the working method of the multi-functional bench for fuel storage and transportation containers further includes evacuating the spent fuel storage and transportation container;

[0047] Evacuating the spent fuel storage and transportation container includes the following steps:

[0048] S4.1. Connect the first interface and the second interface to the spent fuel storage and transportation container respectively;

[0049] S4.2. Start the vacuum pump. The vacuum pump extracts the gas in the spent fuel storage and transportation container. The gas is output from the first interface and the second interface respectively, enters the high-efficiency filter through the vacuum pipeline and the vacuum pump, and then enters the plant ventilation system through the exhaust fan.

[0050] Advantages of the present invention: Integrate the water separator, high-efficiency filter, exhaust fan, cooler, connecting pipeline and each interface in a frame, cooperate with the shielding filter outside the frame, and realize the connection between each device and interface through the connecting pipeline, so as to realize functions such as filling water and exhausting gas, inflating and draining water, and unloading and cooling for the spent fuel storage and transportation container.

[0051] The present invention is helpful for the loading and unloading of high burn-up spent fuel assemblies and reduces radioactive hazards. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The present invention will be further described below in conjunction with the drawings and embodiments. In the drawings:

[0053] Figure 1 is a schematic structural diagram of the bench body in the multi-functional bench for spent fuel storage and transportation containers according to an embodiment of the present invention;

[0054] Figure 2 is Figure 1 a schematic side structural diagram of the shown bench body at an angle after removing the side plate;

[0055] Figure 3 is Figure 2 a top view of the shown bench body after removing the top plate;

[0056] Figure 4 is a connection schematic diagram of the multi-functional bench for spent fuel storage and transportation containers according to an embodiment of the present invention for filling water and exhausting gas (or inflating and draining water);

[0057] Figure 5 is a connection schematic diagram of the multi-functional bench for spent fuel storage and transportation containers according to an embodiment of the present invention for unloading and cooling;

[0058] Figure 6 is a connection schematic diagram of the multi-functional bench for spent fuel storage and transportation containers according to an embodiment of the present invention for evacuating the vacuum. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0059] For a clearer understanding of the technical features, objectives, and effects of the present invention, the specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0060] As Figures 1 - 3 shown, the multi-functional bench for spent fuel storage and transportation containers according to an embodiment of the present invention includes a bench main body and a discharging and cooling device. The bench main body includes a frame 10, a gas-water separator 1, a high-efficiency filter 2, an exhaust fan 3, a cooler 4, connecting pipelines, an interface assembly, and an electrical cabinet 20 disposed within the frame 10; the discharging and cooling device includes a shielding filter 5 disposed outside the frame 10.

[0061] Among them, as Figure 1 shown, the frame 10 is integrally in a frame structure, and the internal space is used to accommodate the frame 10, the gas-water separator 1, the high-efficiency filter 2, the exhaust fan 3, the cooler 4, the connecting pipelines, and the interface assembly, etc. Side plates 11 are respectively provided on each side surface of the frame 10, and the side plates 11 enclose the side surfaces of the frame 10, playing a certain protective role, etc. Preferably, the side plates 11 on at least one side surface are provided to be openable and closable, so as to be able to open and close the side surface of the frame 10, facilitating operations such as the replacement and maintenance of internal components.

[0062] In addition, a lifting ring 12 may be provided at the top of the frame 10 to facilitate the handling and hoisting of the bench main body. Universal wheels 13 are provided at the bottom of the frame 10, and the universal wheels 13 are equipped with a braking device to facilitate the free movement and positioning of the bench main body in the plant. A handle (not shown) may also be provided on at least one side surface of the frame 10 to facilitate the use when moving the bench main body.

[0063] Within the frame 10, the gas-water separator 1, the high-efficiency filter 2, the exhaust fan 3, the cooler 4, and the interface assembly are connected through connecting pipelines, having functions such as transporting and discharging water and gas, drying, and air filtering for the spent fuel storage and transportation container 200. The shielding filter 5 is a large-capacity filter with a shielding function, with a pressure resistance level of 1 Mpa, and is connected to the components within the frame 10 through connecting pipelines to achieve discharging and cooling of the spent fuel storage and transportation container 200, meeting the functional requirements of the multi-functional bench.

[0064] Specifically, the connecting pipelines at least include a first pipeline 21, a second pipeline 22, a third pipeline 23, an exhaust pipeline 24, and a drainage pipeline 25; the interface assembly at least includes a water inlet interface 31, a drainage interface 32, a water inlet and drainage interface 33, an air inlet and exhaust interface 34, and an air inlet interface 35. The water inlet interface 31 is used to connect to a submersible pump 100 to access the water in the filling well; the water inlet and drainage interface 33 and the air inlet and exhaust interface 34 are respectively used to connect to different interfaces on the spent fuel storage and transportation container 200, and the air inlet interface 35 is used to connect to a gas source to access the required gas.

[0065] Combined with Figure 2 andFigure 4 One end of the first pipeline 21 is connected to the water inlet and outlet interface 33, and the other end is connected to the water inlet interface 31 through the first three-way valve 41. Moreover, a humidity sensor 6 and a first liquid level switch 71 are provided on the first pipeline 21; the humidity sensor 6 is used to detect the humidity value in the first pipeline 21, and the first liquid level switch 71 can generate a switch signal according to the liquid level condition in the first pipeline 21.

[0066] One end of the second pipeline 22 is connected to the air inlet and outlet interface 34, and the other end is connected to the inlet of the gas-liquid separator 1. A second liquid level switch 72 is provided on the second pipeline 22.

[0067] The air inlet interface 35 is connected to the second pipeline 22 through the second three-way valve 42, so that when inflation is required, the gas source will pass the gas through the air inlet interface 35, the second three-way valve 42, the second pipeline 22 and the air inlet and outlet interface 34 into the spent fuel storage and transportation container 200.

[0068] The exhaust pipeline 24 is connected between the gas outlet of the gas-liquid separator 1 and the exhaust fan 3. The high-efficiency filter 2 is provided on the exhaust pipeline 24 and is used to filter the gas discharged after being separated by the gas-liquid separator 1. The outlet end of the exhaust fan 3 is used to be connected to the plant ventilation system, so as to transport the gas discharged after being separated by the gas-liquid separator 1 to the plant ventilation system.

[0069] Preferably, the filter element of the high-efficiency air filter 2 uses fiberglass filter paper as the filter material, the continuous working temperature of the filter element reaches 120 °C, and the filtration efficiency reaches 99.99%.

[0070] One end of the drain pipeline 25 is connected to the first three-way valve 41, and the other end is connected to the drain interface 32 and the inlet of the gas-liquid separator 1 through the third three-way valve 43. The drain interface 32 is used to be connected to the canning well through a hose or the like, so as to be able to transport the discharged water into the canning well. A flow meter 81 is provided on the drain pipeline 25 and is used to detect the flow rate.

[0071] As Figure 4 shown, the three interfaces of the first three-way valve 41 are respectively connected to the water inlet interface 31, the first pipeline 21 and the drain pipeline 25. Through the action of the first three-way valve 41, the connection between the water inlet interface 31 and the first pipeline 21, the connection between the first pipeline 21 and the drain pipeline 25, or the connection between the water inlet interface 31 and the drain pipeline 25 can be realized. The second three-way valve 42 is provided on the second pipeline 22. Therefore, its two interfaces are respectively connected to the second pipeline 22, and the other interface is connected to the air inlet interface 35 to realize the connection or disconnection between the second pipeline 22 and the gas source. The three interfaces of the third three-way valve 43 are respectively connected to the drain pipeline 25, the drain interface 32 and the inlet of the gas-liquid separator 1. Through the action of the third three-way valve 43, the connection between the drain pipeline 25 and the drain interface 32, or the connection between the drain pipeline 25 and the inlet of the gas-liquid separator 1 can be realized.

[0072] In addition, one end of the second pipeline 22 far from the air inlet and outlet interface 34 is also connected to the drain pipeline 25 through a three-way joint, so that the second pipeline 22 can also be connected to the inlet of the gas-liquid separator 1 through the third three-way valve 43.

[0073] A drain pipe is provided at the drain outlet at the bottom of the gas-liquid separator 1 for connecting to the canning well, and the water after gas-liquid separation is discharged into the canning well through the drain outlet.

[0074] The unloading cooling device is mainly used during the unloading cooling process. The shielding filter 5 is mainly used to filter possible radioactive dust particles during the unloading cooling process. The unloading cooling device further includes a housing with a radiation shielding function. The shielding filter 5 is arranged inside the housing, and the housing provides special protection for the shielding filter 5 to ensure the safety of on-site operators.

[0075] Combined with Figure 2 and Figure 5 , one end of the third pipeline 23 is connected to the air inlet and outlet interface 34, and the other end is connected to the inlet of the shielding filter 5 through the fourth three-way valve 44. The shell side of the cooler 4 is connected to the first pipeline 21; the tube side of the cooler 4 is connected between the outlet of the shielding filter 5 and the second pipeline 22, so that the media entering the shell side and the tube side of the coolant 4 can perform heat exchange.

[0076] A pressure gauge 7, a temperature sensor 8 and a third liquid level switch 73 are also provided on the third pipeline 23.

[0077] Preferably, the first three-way valve 41 to the fourth three-way valve 44 are respectively electric three-way ball valves.

[0078] Detection devices such as the humidity sensor 6 and the temperature sensor 8 are respectively connected to the electrical cabinet 20 to transmit the detected humidity and temperature data to the electrical cabinet 20. The electrical cabinet 20 collects and processes the received data, so as to control the corresponding devices to perform corresponding actions, such as starting and stopping of pumps, opening and closing of valves, etc.

[0079] In the connecting pipelines, the first pipeline 21, the second pipeline 22, the third pipeline 23, the exhaust pipeline 24 and the drain pipeline 25 can be respectively formed by stainless steel pipelines, which enhances the setting stability and compact layout of the gas-liquid separator 1, the high-efficiency filter 2, the exhaust fan 3, the cooler 4 and the interface assembly in the frame 10. The gas-liquid separator 1, the high-efficiency filter 2, the exhaust fan 3, the cooler 4 and the interface assembly can be arranged vertically in the space of the frame 10 according to the required installation space, and each device is staggered from each other in the horizontal or vertical direction to meet the reasonable layout and connection of the connecting pipelines.

[0080] Electric valves and / or manual valves are also respectively provided on the connecting pipelines to realize the opening and closing of each pipeline.

[0081] The shielding filter 5 is selected with a stainless steel outer frame and a full-metal filter mesh, which is resistant to high temperature and high humidity, reducing the frequency of filter cleaning and maintenance. Among them, the multi-layer corrugated aluminum mesh has the advantages of low initial resistance, high dust capacity, long service life, light weight, compact structure, and convenient for mobile installation, filtering particles ≥5μm. It can be washed with compressed air or cleaned with cleaning liquid for multiple times and reused.

[0082] Further, as Figure 2 and Figure 6 shown, the bench body further includes a vacuum pumping device arranged in the frame 10, a first interface 36 and a second interface 37 respectively used for connecting with the spent fuel storage and transportation container 200. The vacuum pumping device includes a vacuum pumping pipeline 91, a vacuum pump 92 and a vacuum gauge 93.

[0083] One end of the vacuum pumping pipeline 91 is respectively connected to the first interface 36 and the second interface 37, the other end is connected to the vacuum pump 92, and the vacuum gauge 93 is arranged on the vacuum pumping pipeline 91; the outlet of the vacuum pump 92 is connected to the inlet of the high-efficiency filter 2.

[0084] Combined with Figure 3 and Figure 6 , the vacuum pumping device may further include an oil filter 94, connected to the outlet end of the vacuum pump 92, filtering the gas pumped out by the vacuum pump 92 and then sending it to the high-efficiency filter 2.

[0085] The vacuum pumping pipeline 91 also has an interface for accessing a gas source (such as a helium gas cylinder) 300. The first interface 36 and the second interface 37 can also be connected to the gas source (such as a helium gas cylinder) 300 through the vacuum pumping pipeline 91 to realize helium filling of the spent fuel storage and transportation container 200. Valves 361 and 362 are respectively arranged on the branches of the vacuum pumping pipeline 91 connected to the first interface 36 and the second interface 37 to control the on-off.

[0086] The vacuum pumping device is used to pump vacuum for the spent fuel storage and transportation container 200. After the spent fuel storage and transportation container 200 is pumped to vacuum, it can be filled with helium gas in cooperation with the helium gas cylinder. A valve 901 is arranged between the vacuum gauge 93 and the vacuum pump 92, and this valve 901 is closed when helium gas needs to be filled.

[0087] The working method of the multi-functional bench for the spent fuel storage and transportation container of the present invention includes filling water and exhausting air, filling gas and draining water, and discharging and cooling for the spent fuel storage and transportation container 200, and is applicable to fuel plants of various reactor types and spent fuel storage and transportation containers of various models.

[0088] Filling the spent fuel storage and transportation container 200 with water and exhausting air is a process of filling the empty spent fuel storage and transportation container 200 with water to discharge the internal gas. Specifically, the submersible pump 100 pumps the water in the water pool into the spent fuel storage and transportation container 200 through the pipeline and the water inlet and outlet interface 33, and presses the gas in the spent fuel storage and transportation container 200 out through the air inlet and outlet 34, and after gas-water separation and filtration, it is discharged to the plant ventilation system until the spent fuel storage and transportation container 200 is filled with water, providing shielding and cooling functions for the next step of loading spent fuel.

[0089] Reference Figure 2 and Figure 4 , filling the spent fuel storage and transportation container 200 with water and exhausting air may include the following steps:

[0090] S1.1. Connect the submersible pump 100 to the water inlet interface 31 and place the submersible pump 100 into the canning well. The first three-way valve 41 connects the water inlet interface 31 and the first pipeline 21, and the water inlet and outlet interface 33 and the air inlet and outlet interface 34 are respectively connected to the spent fuel storage and transportation container 200.

[0091] In step S1.1, first remove the outer cover of the spent fuel storage and transportation container 200, then remove the air inlet and outlet hole cover and the water inlet and outlet hole cover on the inner cover of the spent fuel storage and transportation container 200, connect the water inlet and outlet pipes and the air inlet and outlet pipes to the water inlet and outlet interface 33 and the air inlet and outlet interface 34 and the corresponding water inlet and outlet and air inlet and outlet of the spent fuel storage and transportation container 200 respectively, and confirm that the exhaust fan 3 has been connected to the plant ventilation system through the exhaust duct.

[0092] Flow regulating valves 101 and flow meters 102 are also respectively provided on the connecting pipeline between the submersible pump 100 and the water inlet interface 31.

[0093] S1.2. Start the submersible pump 100. The submersible pump 100 pumps water from the canning well, and the water flow sequentially passes through the submersible pump 100, the water inlet interface 31, the first pipeline 21 and the water inlet and outlet interface 33 into the spent fuel storage and transportation container 200.

[0094] Among them, before starting the submersible pump 100, first start the exhaust fan 3, and the third three-way valve 43 connects the second pipeline 22 and the inlet of the gas-water separator 1.

[0095] The gas discharged from the spent fuel storage and transportation container 200 enters the second pipeline 22 through the air inlet and outlet interface 34, sequentially passes through the second three-way valve 42 and the second liquid level switch 72 into the gas-water separator 1, and after removing the moisture, it enters the plant ventilation system through the exhaust pipeline 24, the high-efficiency filter 2 and the exhaust fan 3.

[0096] The water at the bottom of the gas-water separator 1 is automatically discharged to the canning well through the solenoid valve and the drain pipe.

[0097] S1.4. After the spent fuel storage and transportation container 200 is filled with water, the water overflows from the air inlet and outlet interface 34, triggering the second liquid level switch 72, and the submersible pump 100 stops pumping water, completing the water filling and air exhausting work. The exhaust fan 3 stops automatically after running for a period of time.

[0098] Inflating and draining the spent fuel storage and transportation container 200 is a process of discharging the cooling water inside the spent fuel storage and transportation container 200 filled with spent fuel by injecting gas. Specifically, the plant compressed air is decompressed by the pressure reducing valve to meet the requirements and then filled into the spent fuel storage and transportation container 200 through the pipeline from the air inlet and outlet 34. The cooling water in the spent fuel storage and transportation container 200 is discharged to the water pool through the pipeline from the water inlet and outlet 33 by the gas pressure, preparing for the next step of drying the spent fuel storage and transportation container 200.

[0099] Reference Figure 2 and Figure 4 , the inflating and draining of the spent fuel storage and transportation container 200 includes the following steps:

[0100] S2.1. Connect the first three-way valve 41 to the first pipeline 21 and the drainage pipeline 25, connect the drainage interface 32 to the canning well, and connect the third three-way valve 43 to the drainage interface 32 and the drainage pipeline 25. The air inlet interface 35 is connected to the air source (plant air source) through the solenoid valve 202 and the pressure reducing valve 201. The second three-way valve 42 connects the air inlet interface 35 and the air inlet and outlet interface 34, and the water inlet and outlet interface 33 and the air inlet and outlet interface 34 are respectively connected to the spent fuel storage and transportation container 200.

[0101] S2.2. Start the air source. The compressed air enters the spent fuel storage and transportation container 200 through the air inlet interface 35, the second pipeline 22 and the air inlet and outlet interface 34. The gas pressure presses the water in the spent fuel storage and transportation container 200 out of the water inlet and outlet interface 33, along the first pipeline 21, successively through the first liquid level switch 71 and the humidity sensor 6 and the first three-way valve 41 into the drainage pipeline 25, and then through the third three-way valve 43 and the drainage interface 32 along the drainage pipeline 25 into the canning well.

[0102] S2.3. When the first liquid level switch 71 on the first pipeline 21 detects that there is no water flow passing through, the solenoid valve 202 cuts off the air source. At the same time, the third three-way valve 43 connects the drainage pipeline 25 and the air-water separator 1. Start the exhaust fan 3, and then the solenoid valve 202 reconnects the air source. The gas pressure presses the gas in the spent fuel storage and transportation container 200 out, successively through the first liquid level switch 71, the humidity sensor 6 and the first three-way valve 41 into the drainage pipeline 25, and then discharged to the air-water separator 1 along the drainage pipeline 25 through the third three-way valve 43. The gas separated by the air-water separator 1 then enters the plant ventilation system through the exhaust pipeline 24, the high-efficiency filter 2 and the exhaust fan 3.

[0103] The water precipitated in the gas-water separator 1 is automatically discharged into the canning well through the solenoid valve and the drain pipe.

[0104] S2.4. Continuously charge the spent fuel storage and transportation container 200 with gas. After the humidity detected by the humidity sensor 6 on the first pipeline 21 reaches the humidity set value, it indicates that the spent fuel assembly inside the spent fuel storage and transportation container 200 has been dried, and the inflation drying process ends. The solenoid valve 202 cuts off the gas source, and the gas source stops supplying gas. The exhaust fan 3 stops running after running for a period of time.

[0105] Continuously charge the compressed air into the spent fuel storage and transportation container 200 after the above inflation and drainage to air-dry the inner surface of the spent fuel storage and transportation container 200 and the outer surface of the fuel assembly, so as to realize the inflation drying of the spent fuel storage and transportation container 200 and prepare for the next step of vacuum pumping.

[0106] The inflation drying and inflation drainage are a continuous process, using dry gas to displace the water vapor in the gasified and dispersed state in the container to dry the outer surface of the spent fuel assembly and the inner surface of the container. During this process, the solenoid valve at the drain port of the gas-water separator 1 is closed to prevent the radioactive gas inside the gas-water separator 1 from escaping.

[0107] Reference Figure 2 And Figure 5 , the unloading and cooling of the spent fuel storage and transportation container 200 includes the following steps:

[0108] S3.1. Water filling and exhaust cooling, including:

[0109] S3.1.1. Connect the submersible pump 100 to the water inlet interface 31 and place the submersible pump 100 into the canning well. The first three-way valve 41 connects the water inlet interface 31 and the first pipeline 21, the third three-way valve 43 connects the drain pipeline 25 and the gas-water separator 1, the fourth three-way valve 44 connects the shielding filter 5 and the third pipeline 23, and the water inlet and outlet interface 33 and the air inlet and outlet interface 34 are respectively connected to the spent fuel storage and transportation container 200.

[0110] In step S3.1.1, first remove the outer cover of the spent fuel storage and transportation container 200, then remove the air inlet and outlet hole cover and the water inlet and outlet hole cover on the inner cover of the spent fuel storage and transportation container 200, connect the water inlet and outlet pipes and the air inlet and outlet pipes to the water inlet and outlet interface 33 and the air inlet and outlet interface 34 and the corresponding water inlet and outlet ports and air inlet and outlet ports of the spent fuel storage and transportation container 200 respectively, and confirm that the exhaust fan 3 is connected to the plant ventilation system through the exhaust duct.

[0111] A flow regulating valve 101 and a flowmeter 102 are respectively provided on the connecting pipeline between the submersible pump 100 and the water inlet interface 31.

[0112] S3.1.2. The submersible pump 100 pumps water from the canning well, and the water flow follows the first pipeline 21, successively passes through the humidity sensor 6 and the first liquid level switch 71, flows through the shell side of the cooler 4, and then enters the spent fuel storage and transportation container 200 through the water inlet and outlet interface 33.

[0113] Among them, before starting the submersible pump 100, start the exhaust fan 3 first.

[0114] S3.1.3. The gas in the spent fuel storage and transportation container 200 is discharged from the air inlet and outlet interface 34 into the third pipeline 23, and follows the third pipeline 23 to successively pass through the pressure gauge 7, the temperature sensor 8, the third liquid level switch 73, the shielding filter 5 and the tube side of the cooler 4, enters the second pipeline 22, follows the second pipeline 22 into the gas-water separator 1, and then follows the exhaust pipeline 24 to be discharged into the plant ventilation system through the high-efficiency filter 2 and the exhaust fan 3.

[0115] S3.2. Hot water replacement cooling, including:

[0116] S3.2.1. After the spent fuel storage and transportation container 200 is filled with water, the water overflows from the air inlet and outlet interface 34 to trigger the second liquid level switch 72, and the submersible pump 100 stops pumping water.

[0117] S3.2.2. The fourth three-way valve 44 connects the third pipeline 23 and the canning well. After the submersible pump 100 is started, it pumps water from the canning well. The water flow follows the first pipeline 21, flows through the shell side of the cooler 4, and then enters the spent fuel storage and transportation container 200 through the water inlet and outlet interface 33. The water in the spent fuel storage and transportation container 200 is discharged from the air inlet and outlet interface 34, and follows the third pipeline 23 to successively pass through the pressure gauge 7, the temperature sensor 8, the third liquid level switch 73 and the fourth three-way valve 44 and is discharged to the canning well.

[0118] S3.2.3. After the temperature detected by the temperature sensor 8 on the third pipeline 23 is less than or equal to the temperature set value (not greater than the threshold value), the hot water replacement cooling is completed, and the submersible pump 100 stops pumping water.

[0119] Furthermore, the working method of the multi-functional bench for the spent fuel storage and transportation container of the present invention further includes evacuating the spent fuel storage and transportation container 200.

[0120] Combined Figure 3 and Figure 6 , evacuating the spent fuel storage and transportation container 200 includes the following steps:

[0121] S4.1. Connect the first interface 36 and the second interface 37 to the spent fuel storage and transportation container 200 respectively.

[0122] S4.2. Start the vacuum pump 92. The vacuum pump 92 extracts the gas in the spent fuel storage and transportation container 200. The gas is output from the first interface 36 and the second interface 37 respectively, enters the high-efficiency filter 2 through the vacuum pipeline 91 and the vacuum pump 92, and then enters the plant ventilation system through the exhaust fan 3.

[0123] When the vacuum gauge 93 detects that the pressure in the spent fuel storage and transportation container 200 drops to 300 Pa, continue to evacuate for a period of time (such as one hour), and then the evacuation is completed.

[0124] After the evacuation is completed, close the valve connecting the vacuum pump 92 (located between the vacuum gauge 93 and the vacuum pump 92) to ensure the vacuum degree inside the spent fuel storage and transportation container 200, and then connect helium gas to perform the helium gas filling operation at 0.1 MPa. The helium gas from the gas source (helium gas cylinder) 300 passes through the solenoid valve 301, the valve 302 and the pressure gauge 303 in sequence, and enters the spent fuel storage and transportation container 200 from the first interface 36 and the second interface 37.

[0125] In addition, through the multi-functional bench for the spent fuel storage and transportation container of the present invention, operations such as temporary pressure relief, leak detection, and auxiliary drainage of the spent fuel storage and transportation container 200 can also be carried out.

[0126] For temporary pressure relief, connect the spent fuel storage and transportation container 200 through the second pipeline 22 and the air inlet and outlet interface 34 to allow the gas in the spent fuel storage and transportation container 200 to be discharged and drained into the gas-water separator 1, and finally discharged into the plant ventilation system through the exhaust fan 3.

[0127] For leak detection, the pressure drop method or the mass spectrometer vacuum method can be used.

[0128] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A multi-functional bench for spent fuel storage and transportation containers, characterized in that, It includes a bench body and a discharging and cooling device. The bench body includes a frame, a gas-water separator, a high-efficiency filter, an exhaust fan, a cooler, connecting pipelines and an interface assembly arranged in the frame. The discharging and cooling device includes a shielding filter arranged outside the frame. The interface assembly includes a water inlet interface for connecting a submersible pump, a drain interface, water inlet and drain interfaces and air inlet and exhaust interfaces respectively for connecting a spent fuel storage and transportation container, and an air inlet interface for connecting an air source. The connecting pipelines include a first pipeline, a second pipeline, a third pipeline, an exhaust pipeline and a drain pipeline. One end of the first pipeline is connected to the water inlet and drain interface, and the other end is connected to the water inlet interface through a first three-way valve. One end of the second pipeline is connected to the air inlet and exhaust interface, and the other end is connected to the inlet of the gas-water separator. The air inlet interface is connected to the second pipeline through a second three-way valve. The exhaust pipeline is connected between the air outlet of the gas-water separator and the exhaust fan, and the high-efficiency filter is arranged on the exhaust pipeline. One end of the drain pipeline is connected to the first three-way valve, and the other end is connected to the drain interface and the inlet of the gas-water separator through a third three-way valve. The shell side of the cooler is connected to the first pipeline. One end of the third pipeline is connected to the air inlet and exhaust interface, and the other end is connected to the inlet of the shielding filter through a fourth three-way valve. The tube side of the cooler is connected between the outlet of the shielding filter and the second pipeline. A humidity sensor and a first liquid level switch are arranged on the first pipeline. A second liquid level switch is arranged on the second pipeline. A pressure gauge and a temperature sensor are arranged on the third pipeline. The bench body further includes a vacuum pumping device arranged in the frame, a first interface and a second interface respectively for connecting with a spent fuel storage and transportation container. The vacuum pumping device includes a vacuum pumping pipeline, a vacuum pump and a vacuum gauge. One end of the vacuum pumping pipeline is respectively connected to the first interface and the second interface, and the other end is connected to the vacuum pump. The vacuum gauge is arranged on the vacuum pumping pipeline. The outlet of the vacuum pump is connected to the inlet of the high-efficiency filter.

2. The multi-functional bench for spent fuel storage and transportation containers according to claim 1, characterized in that A flowmeter is arranged on the drain pipeline.

3. The multi-functional bench for spent fuel storage and transportation containers according to claim 1, characterized in that, A drain pipe is arranged at the drain outlet of the gas-water separator for connecting to a canning well.

4. The multi-functional bench for spent fuel storage and transportation containers according to claim 1, characterized in that The first three-way valve to the fourth three-way valve are respectively electric three-way ball valves.

5. The multi-functional bench for spent fuel storage and transportation containers according to claim 1, characterized in that, The discharging and cooling device further includes a housing with a radiation shielding function, and the shielding filter is arranged in the housing.

6. The multi-functional bench for spent fuel storage and transportation containers according to claim 1, characterized in that, The bench body further includes side plates arranged on each side surface of the frame. The side plates of at least one side surface can be opened and closed.

7. The multi-functional bench for spent fuel storage and transportation containers according to claim 1, characterized in that, The bench body further includes an electric cabinet installed in the frame. The electric cabinet is respectively connected to the humidity sensor and the temperature sensor to collect and process the data detected by the humidity sensor and the temperature sensor.

8. The multi-functional bench for spent fuel storage and transportation containers according to any one of claims 1-7, characterized in that Lifting rings are arranged at the top of the frame.

9. The multi-functional bench for spent fuel storage and transportation containers according to any one of claims 1-7, characterized in that Universal wheels with braking devices are arranged at the bottom of the frame.

10. The multi-functional bench for spent fuel storage and transportation containers according to any one of claims 1-7, characterized in that, Handles are arranged on at least one side surface of the frame.

11. A working method of the multi-functional bench for spent fuel storage and transportation containers according to any one of claims 1-10, characterized in that, It includes filling water and exhausting air, filling air and draining water, and discharging and cooling for a spent fuel storage and transportation container. Filling water and exhausting air for a spent fuel storage and transportation container includes the following steps: S1.

1. Connect the submersible pump to the water inlet interface and place the submersible pump into the canning well. Connect the first three-way valve to the water inlet interface and the first pipeline, and connect the water inlet and drainage interface and the air inlet and exhaust interface to the spent fuel storage and transportation container respectively. S1.

2. Start the submersible pump. The submersible pump pumps water from the canning well, and the water flow passes through the submersible pump, the water inlet interface, the first pipeline, and the water inlet and drainage interface in sequence and enters the spent fuel storage and transportation container. S1.

3. The gas discharged from the spent fuel storage and transportation container enters the second pipeline through the air inlet and exhaust interface, and passes through the second three-way valve and the second liquid level switch in sequence and enters the gas-water separator. After removing the moisture, it enters the plant ventilation system along the exhaust pipeline through the high-efficiency filter and the exhaust fan. S1.

4. After the spent fuel storage and transportation container is filled with water, the water overflows from the air inlet and exhaust interface and triggers the second liquid level switch, and the submersible pump stops pumping water. The steps for filling the spent fuel storage and transportation container with gas and draining water include the following steps: S2.

1. Connect the first three-way valve to the first pipeline and the drainage pipeline, connect the drainage interface to the canning well, and connect the third three-way valve to the drainage interface and the drainage pipeline; connect the air inlet interface to the gas source; connect the second three-way valve to the air inlet interface and the air inlet and exhaust interface, and connect the water inlet and drainage interface and the air inlet and exhaust interface to the spent fuel storage and transportation container respectively. S2.

2. Start the gas source. Compressed air enters the spent fuel storage and transportation container through the air inlet interface, the second pipeline, and the air inlet and exhaust interface; the gas pressure presses the water in the spent fuel storage and transportation container out from the water inlet and drainage interface, and enters the canning well along the first pipeline, the drainage pipeline, and the drainage interface. S2.

3. When the first liquid level switch on the first pipeline detects that there is no water flow passing through, connect the third three-way valve to the drainage pipeline and the gas-water separator; start the exhaust fan, and the gas pressure presses the gas in the spent fuel storage and transportation container out and discharges it into the gas-water separator, and the gas then enters the plant ventilation system along the exhaust pipeline through the high-efficiency filter and the exhaust fan. S2.

4. After the humidity detected by the humidity sensor on the first pipeline reaches the humidity set value, the gas source stops supplying gas. The steps for discharging and cooling the spent fuel storage and transportation container include the following steps: S3.

1. Fill with water, exhaust gas, and cool down. S3.1.

1. Connect the submersible pump to the water inlet interface and place the submersible pump into the canning well. Connect the first three-way valve to the water inlet interface and the first pipeline, connect the third three-way valve to the drainage pipeline and the gas-water separator, connect the fourth three-way valve to the shielding filter and the third pipeline, and connect the water inlet and drainage interface and the air inlet and exhaust interface to the spent fuel storage and transportation container respectively. S3.1.

2. The submersible pump pumps water from the canning well, and the water flow passes through the first pipeline, flows through the shell side of the cooler, and then enters the spent fuel storage and transportation container through the water inlet and drainage interface. S3.1.

3. The gas in the spent fuel storage and transportation container is discharged from the air inlet and exhaust interface and enters the third pipeline. It passes through the shielding filter and the tube side of the cooler in sequence along the third pipeline and enters the second pipeline. It enters the gas-water separator along the second pipeline, and then enters the plant ventilation system along the exhaust pipeline through the high-efficiency filter and the exhaust fan. S3.

2. Replace with hot water and cool down. S3.2.

1. After the spent fuel storage and transportation container is filled with water, the water overflows from the air inlet and outlet interface to trigger the second liquid level switch, and the submersible pump stops pumping water. S3.2.

2. The fourth three-way valve connects the third pipeline and the canning well. After the submersible pump starts, it pumps water from the canning well. The water flows along the first pipeline, passes through the shell side of the cooler, and then enters the spent fuel storage and transportation container through the air inlet and outlet interface. The water in the spent fuel storage and transportation container is discharged from the air inlet and outlet interface, and is discharged to the canning well along the third pipeline through the fourth three-way valve. S3.2.

3. After the temperature detected by the temperature sensor on the third pipeline is less than or equal to the temperature set value, the submersible pump stops pumping water.

12. The working method of the multi-functional bench for spent fuel storage and transportation containers according to claim 11, characterized in that, It also includes evacuating the spent fuel storage and transportation container. Evacuating the spent fuel storage and transportation container includes the following steps: S4.

1. Connect the first interface and the second interface to the spent fuel storage and transportation container respectively. S4.

2. Start the vacuum pump. The vacuum pump extracts the gas in the spent fuel storage and transportation container. The gas is output from the first interface and the second interface respectively, enters the high-efficiency filter through the vacuum pipeline and the vacuum pump, and then enters the plant ventilation system through the exhaust fan.

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