Verification system and method for off-core purge of high temperature gas-cooled reactor spoiler

Abstract

The present invention proposes a verification system and method for off-core purging of a high-temperature gas-cooled reactor baffle, which belongs to the technical field of high-temperature gas-cooled reactors. The verification system of the present invention includes: a mounting block, a purge air intake duct and a fan; a baffle is installed on the mounting block, one end of the purge air intake duct is connected to a ball receiving position or a ball delivery position of the baffle, and the fan is connected to the other end of the purge air intake duct to purge the dust in the baffle, and by establishing a relationship between the gas purge flow rate and the dust cleaning effect in the baffle, the minimum gas purge flow rate is determined, and the minimum gas purge speed under the effective dust cleaning condition of the baffle is obtained, providing data input for the regular purge work of the baffle on the demonstration project site, and after being applied to the regular purge work of the baffle in the demonstration project, the graphite dust accumulated in the equipment is effectively collected, and the expected purpose of regular cleaning is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of high temperature gas-cooled reactors, and in particular relates to a verification system and method for off-core purge of a spoiler of a high temperature gas-cooled reactor. Background Art

[0002] As an important equipment of high temperature gas-cooled reactor nuclear power plants, the baffle plays an important role in the unified transportation of spherical fuel elements and the effective distribution of gas flow between lifting pipelines. A total of six baffles are arranged in the demonstration project. Under rated operating conditions, a single baffle operates 6,000 times a day to ensure that the primary core can load new fuel, unload spent fuel, and circulate core fuel elements according to design requirements.

[0003] Since the high-temperature gas-cooled reactor demonstration project started nuclear operation in August 2021, the baffle has transported more than 1 million fuel elements. Due to its own functional requirements, the baffle is arranged at the lowest point of the nuclear island plant. During the operation of the reactor, the graphite dust generated during the movement of the spherical elements in the core and fuel loading and unloading system spherical flow pipelines inevitably falls into the baffle and the upstream and downstream connected pipelines. The baffle body and the upstream and downstream pipelines have accumulated a certain amount of radioactive doses. The accumulation of these graphite dusts inside the baffle not only affects the normal flow of the spherical elements, but may also cause the bearings inside the baffle to rotate and become stuck, further causing equipment failure.

[0004] Therefore, it is necessary to develop an online dust cleaning method to effectively remove the graphite dust accumulated inside the baffle and improve the continuous and stable operation capability of the equipment.

[0005] However, if the purge capability verification test is carried out on the baffle body, not only will foreign matter be introduced into the nuclear operation system, there will be uncontrollable risks in the test process, but also the test personnel will be inevitably exposed to radioactivity due to the disassembly and assembly of the equipment. In addition, the field of high-temperature nuclear power reactors has not yet carried out tests related to the gas purge flow rate and the dust cleaning effect in the inclined arrangement equipment, resulting in a lack of comparative test support for the regular purge work of the demonstration project baffle.

[0006] Therefore, it is necessary to carry out a spoiler purge capability verification test outside the reactor, that is, to develop a test system and test method suitable for off-reactor verification of spoiler purge capability based on the on-site installation and operation of the spoiler. Summary of the invention

[0007] The present invention aims to solve at least one of the technical problems existing in the prior art and provides a verification system and method for external purge of a high temperature gas-cooled reactor spoiler.

[0008] In one aspect of the present invention, a verification system for off-core purge of a high temperature gas-cooled reactor spoiler is provided, the verification system comprising:

[0009] A mounting block, on which a baffle is mounted;

[0010] A purge air intake pipeline, one end of which is connected to a ball receiving position or a ball delivering position of the baffle;

[0011] A fan is connected to the other end of the purge air inlet duct to purge the dust in the spoiler, and a minimum gas purge flow rate is determined by establishing a relationship between the gas purge flow rate and the dust cleaning effect in the spoiler.

[0012] Optionally, a buffer tank is further provided on the purge air intake pipeline;

[0013] The buffer tank is used to mix the gas in the purge air intake pipeline evenly and then output it to the baffle.

[0014] Optionally, a pressure reducing valve for reducing gas pressure is further provided on the purge air intake pipeline, and the pressure reducing valve is located between the buffer tank and the baffle.

[0015] Optionally, a flow meter for detecting gas flow is further provided on the purge air inlet pipeline, and the flow meter is located between the buffer tank and the fan.

[0016] Optionally, when the ball receiving position of the baffle is connected to the purge air intake duct, the ball delivering position of the baffle is connected to a purge air exhaust duct;

[0017] When the ball delivery position of the baffle is connected to the purge air intake pipeline, the ball receiving position of the baffle is connected to the purge air exhaust pipeline.

[0018] Another aspect of the present invention provides a verification method for the off-core purge of a high temperature gas-cooled reactor spoiler. According to the verification system described above, the verification method comprises:

[0019] scattering a preset mass of graphite dust linearly in the baffle;

[0020] Start the fan and set the gas purge flow rate to perform at least one purge test on the dust in the baffle until the dust retention in the baffle is less than the preset retention amount, and obtain the lowest gas purge flow rate under the condition of effective dust cleaning inside the baffle.

[0021] Optionally, the performing at least one purge test on the dust in the baffle comprises:

[0022] Set the initial gas purge flow rate to purge the dust in the baffle once;

[0023] Determining whether the actual amount of dust remaining in the baffle is less than a preset amount;

[0024] In response to the actual dust retention amount in the baffle being less than the preset dust retention amount, completing the purge test;

[0025] In response to the actual dust retention amount in the baffle being greater than the preset retention amount, the gas purge flow rate is gradually increased by a preset gas speed increment to perform a single purge on the dust in the baffle again.

[0026] Optionally, the preset gas velocity increment range is 2.0 m / s-3.0 m / s; and / or,

[0027] The single purge time ranges from 8 minutes to 12 minutes.

[0028] Optionally, the preset retention amount is 10% of the initial dust amount in the baffle.

[0029] Optionally, when the dust in the ball receiving position of the baffle is purged once, the initial gas purge flow rate ranges from 4m / s to 6m / s;

[0030] When the dust in the ball delivery position of the baffle is purged once, the initial gas purge flow rate ranges from 14m / s to 16m / s.

[0031] The present invention proposes a verification system and method for off-core purge of a high-temperature gas-cooled reactor baffle, the verification system comprising: a mounting block, on which a baffle is mounted; a purge air intake duct, one end of which is connected to a ball receiving position or a ball delivery position of the baffle; a blower, which is connected to the other end of the purge air intake duct, and by establishing a relationship between the gas purge flow rate and the dust cleaning effect inside the baffle, the minimum gas purge flow rate is determined. The present invention establishes a relationship between the purge flow rate of the purge pipeline of the baffle and the online cleaning effect of graphite dust, obtains the minimum gas purge speed under the effective dust cleaning condition inside the baffle, provides data input for the regular purge work of the baffle on the demonstration project site, and the graphite dust accumulated in the equipment is effectively collected, achieving the expected purpose of regular cleaning. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of a verification system for external purge of a high temperature gas-cooled reactor spoiler with a press switch according to an embodiment of the present invention;

[0033] Figure 2 It is a structural diagram of a verification system for external purge of a high temperature gas-cooled reactor spoiler in another embodiment of the present invention;

[0034] Figure 3 It is a flowchart of a verification system method for external purge of a high temperature gas-cooled reactor spoiler in another embodiment of the present invention. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present invention.

[0036] Unless otherwise specified, the technical terms or scientific terms used in the present invention shall have the common meanings understood by persons with ordinary skills in the field to which the present invention belongs. The words "include" or "comprises" used in the present invention neither limit the shapes, numbers, steps, actions, operations and / or groups thereof mentioned, nor exclude the presence or addition of one or more other different shapes, numbers, steps, actions, operations and / or groups thereof.

[0037] like Figure 1 and Figure 2 As shown, in one aspect of the present invention, a verification system 100 for off-core purging of a high-temperature gas-cooled reactor baffle is proposed, characterized in that the system comprises: a mounting block 110, a purge air inlet duct 120 and a fan 130; wherein a baffle 140 is mounted on the mounting block 110; one end of the purge air inlet duct 120 is connected to a ball receiving position or a ball delivering position of the baffle 140; the fan 130 is connected to the other end of the purge air inlet duct 120, and gas is blown into the baffle 140 through the purge air inlet duct 120 to purge the dust in the baffle 140, and the minimum gas purge flow rate is determined by establishing a relationship between the gas purge flow rate and the dust cleaning effect in the baffle.

[0038] The test data obtained by the present invention can be applied to the demonstration project. After the spoiler is regularly purged, the graphite dust accumulated in the equipment is effectively collected, achieving the expected purpose of regular cleaning.

[0039] It should be noted that, in this embodiment, according to the on-site installation layout of the baffles in the high-temperature gas-cooled reactor demonstration project, combined with the particle size and position distribution of graphite dust after long-term operation of the equipment, a test system for off-reactor verification of the baffle purge capability is formulated. The layout of the baffles corresponds to the demonstration project, that is, the baffles are installed on a mounting block. In order to make the baffles match the installation environment in the demonstration project, the mounting block can be tilted to form a structure similar to a wedge block, so that the baffle is located at the lowest point.

[0040] It still needs to be explained that the baffle has a ball receiving position and a ball delivering position. When verifying the purging capacity of the ball receiving position, the purge air intake pipe needs to be connected to the ball receiving position of the baffle. When verifying the purging capacity of the ball delivering position, the purge air intake pipe needs to be connected to the ball delivering position of the baffle.

[0041] Specifically, Figure 1 and Figure 2 As shown, the mounting block 110 is inclined from the first end at the top to the second end at the bottom, that is, the mounting block is inclined downward, and the baffle 140 is arranged on the inclined surface, so that the side of the baffle 140 facing the first end of the mounting block 110 is a ball receiving position, and the side facing the second end of the mounting block 110 is a ball delivering position.

[0042] Furthermore, if Figure 1 As shown, when the ball receiving position of the baffle 140 is connected to the purge air intake pipe 120, the ball delivery position of the baffle 140 is connected to the purge air exhaust pipe 150. Figure 2 As shown, when the ball delivery position of the baffle 140 is connected to the purge intake duct 120 , the ball receiving position of the baffle 140 is connected to the purge exhaust duct 150 .

[0043] It should be further explained that if the baffle purge capability verification test is carried out under helium atmosphere conditions, not only will the pipeline installation quality and welding quality be required to be high, which will increase the time cost, but also the test cost will be increased due to the high cost of the power device driven by helium. In addition, a large number of demonstration project practices have shown that during the large-flow purge of graphite dust, the purge effect is only related to the flow rate of the purge gas, and has nothing to do with the type of medium of the purge gas. Therefore, the purge capability verification test of the baffle in this embodiment is carried out in an air atmosphere, and the data obtained from the test is provided for on-site use in the demonstration project after scientific conversion.

[0044] In some preferred embodiments, the blower may be a Roots blower.

[0045] Furthermore, if Figure 1 and Figure 2 As shown, a buffer tank 160 is also provided on the purge air inlet pipeline 120 for mixing the gas uniformly.

[0046] It should be understood that when the gas is blown into the purge air inlet duct by the fan, there is gas unevenness. To address this, the present embodiment sets a buffer tank in the purge air inlet duct to first collect the gas in the purge air inlet duct, and then fully mix the gas in the buffer tank. After the gas is evenly mixed, it is supplied to the downstream baffle to maintain airflow balance.

[0047] Furthermore, if Figure 1 and Figure 2 As shown, a pressure reducing valve 170 is also provided on the purge air intake pipe 120. The pressure reducing valve 170 is located between the buffer tank 160 and the baffle 140. The pressure reducing valve 170 is used to reduce the gas pressure in the purge air intake pipe 120 to prevent damage to the baffle when the pressure is too high.

[0048] Furthermore, if Figure 1 and Figure 2 As shown, a flow meter 180 is also provided on the purge air intake pipeline 120 . The flow meter 180 is located between the buffer tank 160 and the fan 130 and is used to detect the gas flow in the purge air intake pipeline 120 .

[0049] Based on the verification system of the present invention, the cleaning effect of the dust in the baffle can be evaluated by setting the purge flow rate of the fan. In order to verify the relationship between the purge flow rate of the baffle purge pipeline and the online cleaning effect of graphite dust, the lowest gas purge speed under the effective dust cleaning condition inside the baffle is obtained, which provides data input for the regular purge work of the baffle at the demonstration project site.

[0050] like Figure 3 As shown, another aspect of the present invention, based on the verification system described above, proposes a verification method S200 for external purge of a high temperature gas-cooled reactor spoiler, including steps S210-S220, which will be specifically described in detail below.

[0051] It should be noted that when using the aforementioned verification system for verification, it is necessary to verify that each structure meets the following experimental conditions:

[0052] 1) The test bench for verifying the purge capability of the baffle under air atmosphere has been built;

[0053] 2) The baffle is installed on the test bench in the correct position and flow direction;

[0054] 3) The action control program in the choke driver has been compiled and the equipment is ready for operation;

[0055] 4) The Roots blower used as the power source for the test is in operating condition;

[0056] 5) The flow meter is within the validity period and meets the operating conditions;

[0057] 6) Graphite dust with a particle size less than 2 mm has been prepared.

[0058] After all the above conditions are met, the verification test will begin. The specific steps include:

[0059] S210, scattering a preset mass of graphite dust linearly in the baffle.

[0060] It should be noted that the preset mass of graphite dust can be set according to the ball delivery position and ball receiving position of the baffle. In the demonstration project, the residual dust corresponding to the ball receiving position is generally more than that of the ball delivery position.

[0061] It should be further explained that, since the ball receiving position and the ball delivery position of the baffle need to be purged separately, the position where the graphite dust is scattered needs to be specifically set. For example, when the ball receiving position of the baffle is purged, the graphite dust is scattered to the baffle rotor ball cup and the upstream pipeline. When the ball delivery position of the baffle is purged, the graphite dust is scattered to the baffle rotor ball cup and the downstream pipeline.

[0062] S220, start the fan and set the gas purge flow rate to perform at least one purge test on the dust in the baffle until the actual dust retention in the baffle is less than the preset retention amount, and the lowest gas purge flow rate under the condition of effective dust cleaning inside the baffle is obtained.

[0063] Specifically, after starting the fan, an initial gas purge flow rate can be set to perform a single purge on the dust in the baffle; after the single purge is completed, determine whether the actual dust retention amount in the baffle is less than the preset retention amount; in response to the actual dust retention amount in the baffle being less than the preset retention amount, complete the purge test; in response to the actual dust retention amount in the baffle being greater than the preset retention amount, gradually increase the gas purge flow rate with a preset gas speed increment, and perform a single purge on the dust in the baffle again, and so on, until the actual dust retention amount in the baffle is less than the preset retention amount.

[0064] It should be noted that by using different gas purge flow rates to purge the dust in the baffle, a correlation can be established between the actual amount of dust retained in the baffle and the gas purge flow rate. Based on the correlation, the minimum gas purge speed for effective internal dust cleaning conditions can be determined.

[0065] It should be further explained that the preset gas velocity increment is 2.0 m / s-3.0 m / s, the single purge time is 8 minutes-12 minutes, and the preset retention amount is 10% of the initial dust amount in the baffle.

[0066] It should be noted that when the dust in the receiving position of the baffle is purged once, the initial gas purge flow rate is 4m / s-6m / s; when the dust in the sending position of the baffle is purged once, the initial gas purge flow rate is 14m / s-16m / s.

[0067] The verification method of the present invention can guide the off-core verification test of the spoiler purge capacity. The test avoids the risk of personnel exposure caused by the introduction of radioactive substances and excessive test costs, and obtains the relationship between the purge flow rate and the online cleaning effect of graphite dust. Based on the test results, data input can be provided for the regular on-site purge work of the spoiler.

[0068] The verification method for the external purge of the high temperature gas-cooled reactor spoiler will be specifically described below in conjunction with a specific embodiment:

[0069] Example 1

[0070] This example takes the purging of the ball receiving position of the baffle as an example to explain, including the following steps:

[0071] 1) Move the choke and place the device in the ball receiving position;

[0072] 2) Scatter graphite dust linearly onto the rotor cup of the flow control device and the upstream pipeline, with the amount of dust placed being about 50g;

[0073] 3) Start the Roots blower to carry out the purge test. The purge direction is: upstream pipeline of the baffle → ball cup → inside the box → outside the baffle;

[0074] 4) The initial gas purge flow rate of the test was set to 5 m / s, and the purge time for a single test was 10 minutes;

[0075] 5) After the purge is completed, use an endoscope to check the dust retention inside the baffle. If the dust retention in the baffle exceeds the initial dust amount by about 10%, increase the flow rate and continue the test;

[0076] 6) The purge speed of a single test is gradually increased with 2.5 m / s as the purge gas speed increment step. The single test time at a single flow rate is 10 minutes; for example, after the initial purge, the purge gas speed is increased to 7.5 m / s to purge the dust in the baffle. After a single purge, determine again whether the actual dust retention is less than 10% of the initial dust amount. If it still does not meet the requirements, continue to increase it by 2.5%, that is, purge the dust in the baffle with a purge gas speed of 10 m / s.

[0077] 7) After the single purge test is completed, the endoscope inspection results show that the dust remaining in the baffle does not exceed 10% of the initial dust amount, and the test is completed.

[0078] Based on the above process, the minimum gas purge flow rate for effectively cleaning the graphite dust remaining in the equipment can be obtained when the baffle is in the ball-catching position.

[0079] Example 2

[0080] This example takes the purging of the ball delivery position of the baffle as an example to explain, including the following steps:

[0081] 1) Move the choke and place the device in the ball delivery position;

[0082] 2) Scatter graphite dust linearly into the rotor cup of the flow control device and the downstream pipeline, with the amount of dust placed being about 10g;

[0083] 3) Start the Roots blower to carry out the purge test. The purge direction is: downstream pipeline of the baffle → ball cup → inside the box → outside the baffle;

[0084] 4) The initial gas purge flow rate of the test was set to 15 m / s, and the purge time for a single test was 10 minutes;

[0085] 5) After the purge is completed, use an endoscope to check the dust retention inside the baffle. If the dust retention in the baffle exceeds the initial dust amount by about 10%, increase the flow rate and continue the test;

[0086] 6) The purge speed of a single test is gradually increased with 2.5 m / s as the purge gas speed increment step. The single test time at a single flow rate is 10 minutes; for example, after the initial purge, the purge gas speed is increased to 17.5 m / s to purge the dust in the baffle. After a single purge, determine again whether the actual dust retention is less than 10% of the initial dust amount. If it still does not meet the requirements, continue to increase it by 2.5%, that is, use a purge gas speed of 20 m / s to purge the dust in the baffle.

[0087] 7) After the single purge test is completed, the endoscope inspection results show that the dust remaining in the baffle does not exceed 10% of the initial dust amount, and the test is completed.

[0088] Based on the above process, the minimum gas purge flow rate for effectively cleaning the graphite dust remaining in the baffle device when the baffle is in the ball feeding position can be obtained.

[0089] The present invention also applied the verification system to a demonstration project for testing. Since the demonstration project was put into operation again, the system has been used to regularly purge the baffle. At present, the baffle has accumulated more than 500,000 balls, and no ball jam failure has occurred, and the continuous operation capacity of the equipment has been greatly improved. In order to verify the cleaning effect of gas purge on the dust in the baffle, the equipment was disassembled on site. After visual inspection, no obvious dust accumulation was found in the equipment, and the overall cleanliness was much higher than the cleanliness of the equipment before regular purge. The above situation can effectively illustrate that after the test data obtained by the present invention is applied to the regular purge of the baffle in the demonstration project, the graphite dust accumulated in the equipment is effectively collected, achieving the expected purpose of regular cleaning.

[0090] The present invention provides a verification system and method for off-core purge of a high-temperature gas-cooled reactor spoiler, which has the following beneficial effects:

[0091] First, the present invention establishes the relationship between the purge flow rate of the spoiler purge pipeline and the online cleaning effect of graphite dust, obtains the lowest gas purge speed under the working condition of effective dust cleaning inside the spoiler, provides data input for the regular purge work of the spoiler at the demonstration project site, and provides a technical basis for scientifically and effectively carrying out the regular purge work of the spoiler at the demonstration project site;

[0092] Second, after the test data obtained by the present invention is applied to the regular purge work of the baffle in the demonstration project, the graphite dust accumulated in the equipment is effectively collected, achieving the expected purpose of regular cleaning.

[0093] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A verification method for the off-core purge of a high temperature gas-cooled reactor spoiler, characterized in that: Verification system for external purge of spoiler in high temperature gas-cooled reactor; The verification system comprises: A mounting block, on which a baffle is mounted; A purge air intake pipeline, one end of which is connected to a ball receiving position or a ball delivering position of the baffle; A fan connected to the other end of the purge air inlet duct to purge the dust in the spoiler, and a minimum gas purge flow rate is determined by establishing a relationship between the gas purge flow rate and the dust cleaning effect in the spoiler; The verification method comprises: scattering a preset mass of graphite dust linearly in the baffle; Start the fan and set the gas purge flow rate to perform at least one purge test on the dust in the spoiler until the dust retention in the spoiler is less than the preset retention amount, and obtain the lowest gas purge flow rate under the condition of effective dust cleaning inside the spoiler; The dust in the baffle is purged at least once, including: Set the initial gas purge flow rate to purge the dust in the baffle once; when the dust in the baffle receiving position is purged once, the initial gas purge flow rate range is 4m / s-6m / s; when the dust in the baffle delivering position is purged once, the initial gas purge flow rate range is 14m / s-16m / s; Determining whether the actual amount of dust remaining in the baffle is less than a preset amount; In response to the actual dust retention amount in the baffle being less than the preset dust retention amount, completing the purge test; In response to the actual dust retention amount in the baffle being greater than the preset retention amount, the gas purge flow rate is gradually increased at a preset gas speed increment to perform a single purge on the dust in the baffle again.

2. The verification method for the off-core purge of the high temperature gas-cooled reactor spoiler according to claim 1, characterized in that: The preset gas velocity increment range is 2.0 m / s-3.0 m / s; and / or, The single purge time ranges from 8 minutes to 12 minutes.

3. The verification method for the off-core purge of the high temperature gas-cooled reactor spoiler according to claim 1, characterized in that: The preset retention amount is 10% of the initial dust amount in the baffle.

4. A verification system for high temperature gas-cooled reactor spoiler off-core purge, characterized in that: Using the verification method according to any one of claims 1 to 3, the verification system comprises: A mounting block, on which a baffle is mounted; A purge air intake pipeline, one end of which is connected to a ball receiving position or a ball delivering position of the baffle; A fan is connected to the other end of the purge air inlet duct to purge the dust in the spoiler, and a minimum gas purge flow rate is determined by establishing a relationship between the gas purge flow rate and the dust cleaning effect in the spoiler.

5. The verification system for high temperature gas-cooled reactor spoiler external purge according to claim 4, characterized in that: A buffer tank is also provided on the purge air intake pipeline; The buffer tank is used to mix the gas in the purge air intake pipeline evenly and then output it to the baffle.

6. The verification system for high temperature gas-cooled reactor spoiler external purge according to claim 5, characterized in that: A pressure reducing valve for reducing gas pressure is also provided on the purge air inlet pipeline, and the pressure reducing valve is located between the buffer tank and the baffle.

7. The verification system for high temperature gas-cooled reactor spoiler off-core purge according to claim 6, characterized in that: A flow meter for detecting gas flow is also provided on the purge air inlet pipeline, and the flow meter is located between the buffer tank and the fan.

8. The verification system for high temperature gas-cooled reactor spoiler external purge according to any one of claims 4 to 7, characterized in that: When the ball receiving position of the baffle is connected to the purge air intake pipeline, the ball delivering position of the baffle is connected to the purge air exhaust pipeline; When the ball delivery position of the baffle is connected to the purge air intake pipeline, the ball receiving position of the baffle is connected to the purge air exhaust pipeline.

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