A method for solving the blockage upstream of the choke of a high temperature gas cooled reactor fuel handling system

Abstract

This invention provides a method for resolving upstream blockage of a flow restrictor in a high-temperature gas-cooled reactor fuel loading and unloading system, comprising the following steps: establishing a purging branch, the purging branch including an inlet pipe and a return pipe; the input end of the inlet pipe is connected to the outlet of a helium compressor, and the output end is connected to the flow restrictor; the input end of the return pipe is connected to the new fuel loading pipeline; closing the first isolation valve near the primary loop on the core main cycle unloading pipeline; opening the second isolation valve on the new fuel loading pipeline, thereby forming a passage between the inlet pipe, the flow restrictor, the connection between the new fuel loading pipeline and the core main cycle unloading pipeline, the new fuel loading pipeline, and the return pipe; helium generated by the helium compressor sequentially passes through the inlet pipe and the flow restrictor into the connection between the new fuel loading pipeline and the core main cycle unloading pipeline to purge the bridging. One technical advantage of this invention is that it can quickly resolve upstream blockage of the flow restrictor and offers high safety.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature gas-cooled reactor technology, specifically relating to a method for solving the upstream blockage of the flow restrictor in the fuel loading and unloading system of a high-temperature gas-cooled reactor. Background Technology

[0002] High-temperature gas-cooled reactors (HTGRs) require continuous fuel cycling to maintain sufficient residual reactivity in the reactor core. This involves unloading spent fuel that has reached burnup and loading enough new fuel pellets to compensate for the loss of residual reactivity due to the daily unloading and burnup of spent fuel pellets. The main circulation pipeline measures the burnup of the unloaded fuel pellets. Fuel pellets that have reached the burnup standard are identified as spent fuel pellets and sent to a dedicated unloading pipeline. Fuel pellets that have not reached the burnup standard are sent from the main circulation unloading pipeline to the upstream of the main circulation baffle. The baffle activates and sends them to the main circulation lift pipeline, from where they are returned to the core. Simultaneously, when new fuel pellets need to be loaded, they can be sent upstream of the main circulation baffle via a new fuel pellet storage device. The baffle activates and sends them to the main circulation lift pipeline, thus delivering the new fuel to the core. Therefore, the upstream of the baffle connects both the main circulation unloading pipeline and the new fuel loading pipeline. However, when the main cycle unloading pipeline and the new fuel loading pipeline pass through fuel balls simultaneously, there is a possibility of bridging at the connection between the new fuel loading pipeline and the main cycle unloading pipeline, which could lead to blockage upstream of the flow restrictor; or, if there are too many fuel balls upstream of the flow restrictor, bridging may occur at the connection between the new fuel loading pipeline and the main cycle unloading pipeline, which could also lead to blockage upstream of the flow restrictor.

[0003] Currently, the method for resolving blockages upstream of the flow restrictor is to shut down the fuel loading and unloading system. This involves first switching the atmosphere in the fuel loading and unloading system, and then opening the pipeline for unblocking. However, the atmosphere switching process for the fuel loading and unloading system takes a considerable amount of time, and when combined with maintenance and system recovery time, the overall process is lengthy, resulting in low efficiency in resolving the blockage. If the fuel loading and unloading system is unavailable for an extended period, it may lead to reduced unit load. Furthermore, if there are burnt fuel balls at the blockage location upstream of the flow restrictor, maintenance personnel will be exposed to significant radiation doses when performing maintenance through system openings, posing a safety risk. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art, and to provide a new technical solution for solving the upstream blockage of the flow restrictor in the fuel loading and unloading system of a high-temperature gas-cooled reactor.

[0005] According to one aspect of the present invention, a method for resolving upstream blockage of a flow restrictor in a high-temperature gas-cooled reactor fuel loading and unloading system is provided, comprising the following steps:

[0006] Step S100: Establish a purging branch, which includes an inlet pipe and a return pipe; the inlet pipe is connected to the outlet of the helium compressor and the outlet is connected to a flow restrictor; the inlet pipe is connected to the new fuel charging line and the outlet is connected to the return port of the helium compressor.

[0007] Step S200: Close the first isolation valve on the main circulation unloading pipeline of the reactor core near the primary loop; wherein, the first isolation valve is used to control the on / off state between the primary loop and the main circulation unloading pipeline of the reactor core.

[0008] Step S300: Open the second isolation valve on the new fuel charging pipeline; the connection between the air inlet pipe, the flow restrictor, the new fuel charging pipeline and the core main circulation unloading pipeline;

[0009] The new fuel loading pipeline and return gas pipeline can form a passageway;

[0010] In step S400, the helium generated by the helium compressor passes through the inlet pipe and the flow barrier in sequence and enters the connection between the new fuel charging pipeline and the core main circulation unloading pipeline to purge the bridging and resolve the blockage upstream of the flow barrier.

[0011] Optionally, the new fuel charging pipeline is connected to the new fuel temporary storage device, and the connection point between the return gas pipe and the new fuel charging pipeline is located between the new fuel temporary storage device and the second isolation valve.

[0012] Optionally, the fuel ball downstream of the flow stopper may be emptied before the blockage upstream of the flow stopper is resolved.

[0013] Optionally, a pellet separator and a distributor are sequentially installed on the main circulation unloading pipeline of the core; the first isolation valve is located between the primary loop and the pellet separator.

[0014] Optionally, a return valve is provided on the return pipe;

[0015] The return air valve is used to control the opening or closing of the return air pipe;

[0016] When resolving the blockage upstream of the flow restrictor, the return gas valve is in the open state to form a passage between the inlet pipe, the flow restrictor, the connection between the new fuel charging line and the core main circulation unloading line, the new fuel charging line, and the return gas pipe.

[0017] Optionally, the outlet of the helium compressor is connected to a main pipeline and a bypass pipeline, the main pipeline being used to connect to the main circulation boost pipeline; the bypass pipeline being used to connect to the inlet pipeline.

[0018] Optionally, the main pipeline can be shut off and the bypass pipeline can be opened before the blockage upstream of the flow restrictor is resolved.

[0019] Optionally, an intake electric valve is provided on the intake pipe.

[0020] Optionally, the helium compressor is equipped with a main gas supply valve;

[0021] When resolving the blockage upstream of the flow restrictor, first open the main air supply valve, and then open the aforementioned electric air intake valve.

[0022] Optionally, during the process of purging the bridging at the connection between the helium generated by the helium compressor and the connection between the new fuel charging pipeline and the core main circulation unloading pipeline, a listening device is used to judge the disturbance of the fuel ball bridging. When the collision sound of the fuel ball and the pipeline is heard, the purging is stopped.

[0023] One technical advantage of this invention is that:

[0024] In this embodiment, when bridging occurs at the connection between the new fuel loading pipeline upstream of the flow restrictor and the core main circulation unloading pipeline, the blockage upstream of the flow restrictor is quickly resolved by online purging, avoiding the shutdown of the fuel loading and unloading system, effectively improving the utilization rate of the fuel loading and unloading system, and thus ensuring the unit's load rate.

[0025] In addition, this method for resolving upstream blockage of the flow restrictor in the fuel loading and unloading system of a high-temperature gas-cooled reactor does not require maintenance through system openings, effectively avoiding excessive radiation doses to personnel and ensuring high safety. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating a method for resolving upstream blockage of a flow restrictor in a high-temperature gas-cooled reactor fuel loading and unloading system, according to an embodiment of the present invention.

[0027] Figure 2 This is a schematic diagram of the connection relationship of the flow restrictor in a method for solving upstream blockage of the flow restrictor in a fuel loading and unloading system of a high-temperature gas-cooled reactor according to an embodiment of the present invention.

[0028] In the diagram: 1. Inlet pipe; 2. Return pipe; 3. Flow baffle; 4. New fuel loading line; 5. First isolation valve; 6. Second isolation valve; 7. Core main circulation unloading line;

[0029] 8. New fuel storage device; 9. Particle separator; 10. Distributor; 11. Return gas valve;

[0030] 12. Intake electric valve; 13. Downstream of the flow restrictor; 14. Primary circuit. Detailed Implementation

[0031] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0032] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0033] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0034] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0035] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0036] See Figure 1 and Figure 2According to one aspect of the present invention, a method for resolving upstream blockage of a flow restrictor in a high-temperature gas-cooled reactor fuel loading and unloading system is provided, which is used to resolve upstream blockage of a flow restrictor in a high-temperature gas-cooled reactor fuel loading and unloading system.

[0037] Specifically, the method for resolving upstream blockage of the flow restrictor in the fuel loading and unloading system of a high-temperature gas-cooled reactor includes the following steps:

[0038] Step S100: Establish a purging branch, which includes an inlet pipe 1 and a return pipe 2. The inlet pipe 1 is connected to the outlet of the helium compressor at its input end and to a flow restrictor 3 at its output end. The return pipe 2 is connected to the new fuel loading line 4 at its input end and to the return port of the helium compressor at its output end. The inlet pipe 1 and the return pipe 2 are part of the purging circuit.

[0039] Step S200: Close the first isolation valve 5 on the main core circulation unloading pipeline 7 near the primary loop 14; wherein, the first isolation valve 5 is used to control the on / off state between the primary loop 14 and the main core circulation unloading pipeline 7. Closing the first isolation valve 5 can prevent the purging process from affecting the fuel balls in the upper part of the main core circulation unloading pipeline 7, such as the pellet separator 9 and the distributor 10.

[0040] In step S300, the second isolation valve 6 on the new fuel charging pipeline 4 is opened, and the inlet pipe 1, the flow obstructor 3, the connection between the new fuel charging pipeline 4 and the core main circulation unloading pipeline 7, the new fuel charging pipeline 4, and the return gas pipe 2 can form a passage. The helium compressor, inlet pipe 1, flow obstructor 3, the connection between the new fuel charging pipeline 4 and the core main circulation unloading pipeline 7, the new fuel charging pipeline 4, and the return gas pipe 2 constitute a complete purging circuit.

[0041] In step S400, the helium generated by the helium compressor passes through the inlet pipe 1 and the flow barrier 3 in sequence and enters the connection between the new fuel charging pipeline 4 and the core main circulation unloading pipeline 7 to purge the bridging and resolve the blockage upstream of the flow barrier.

[0042] In this embodiment, when bridging occurs at the connection between the new fuel loading pipeline 4 upstream of the flow restrictor and the core main circulation unloading pipeline 7, the blockage upstream of the flow restrictor is quickly resolved by online purging, avoiding the shutdown of the fuel loading and unloading system, effectively improving the utilization rate of the fuel loading and unloading system, and thus ensuring the unit's load rate.

[0043] In addition, this method for resolving upstream blockage of the flow restrictor in the fuel loading and unloading system of a high-temperature gas-cooled reactor does not require maintenance through system openings, effectively avoiding excessive radiation doses to personnel and ensuring high safety.

[0044] It should be noted that the method for solving the upstream blockage of the flow restrictor in the fuel loading and unloading system of the high-temperature gas-cooled reactor utilizes part of the purging pipeline of the fuel loading and unloading system. Through the flow restrictor 3 of the main circulation, the bridging at the connection between the new fuel loading pipeline 4 and the core main circulation unloading pipeline 7 upstream of the flow restrictor is purged in reverse. The high-pressure helium flow rate with a sufficiently large flow rate can destroy the stable structure at the bridging point and enable it to flow, thereby solving the problem of fuel ball blockage.

[0045] In one embodiment, the baffle housing and the baffle rotor have openings to form a purging channel. The purging circuit can only be purged when the baffle rotor rotates to a preset position. During purging, the rotor remains stationary. When the rotor is in the ball-receiving position, the purging airflow rises; when the rotor is in the ball-feeding position, the purging airflow rises. In this embodiment, during the process of contacting the baffle blockage, the baffle rotor rotates to the ball-feeding position.

[0046] Optionally, the new fuel charging line 4 is connected to the new fuel storage device 8, and the connection point between the return gas pipe 2 and the new fuel charging line 4 is located between the new fuel storage device 8 and the second isolation valve 6. The second isolation valve 6 can control the opening or closing of the new fuel charging line 4, thereby easily purging the circuit to an open or closed state.

[0047] Optionally, the fuel ball downstream of the flow stopper 13 may be emptied before the blockage upstream of the flow stopper is resolved.

[0048] In the above embodiment, the downstream of the flow restrictor 13 is connected to the main circulation lift pipeline. Before the blockage upstream of the flow restrictor is resolved, the fuel ball downstream of the flow restrictor 13 is emptied, which effectively avoids the disturbance of the fuel ball upstream of the flow restrictor during the purging process and ensures the safety of the purging process.

[0049] Optionally, a pellet separator 9 and a distributor 10 are sequentially installed on the main core circulation unloading pipeline 7; the first isolation valve 5 is located between the primary loop 14 and the pellet separator 9. The main core circulation unloading pipeline 7 can be directly connected to the pressure vessel of the primary loop 14. The opening and closing of the main core circulation unloading pipeline 7 can be controlled by the first isolation valve 5, and when the first isolation valve 5 is closed, it effectively prevents disturbance of the fuel pellets upstream of the flow restrictor during the purging process, ensuring the safety of the purging process.

[0050] Optionally, a return air valve 11 is provided on the return air pipe 2;

[0051] The return air valve 11 is used to control the opening or closing of the return air pipe 2;

[0052] When resolving the blockage upstream of the flow restrictor, the return gas valve 11 is in the open state to form a passage between the inlet pipe 1, the flow restrictor 3, the new fuel charging line 4 and the core main circulation unloading line 7, the new fuel charging line 4 and the return gas pipe 2.

[0053] In the above embodiment, the return gas valve 11 can quickly control the opening or closing of the return gas pipe 2, and also helps to form a passage between the inlet pipe 1, the flow obstructor 3, the new fuel charging pipe 4 and the core main cycle unloading pipe 7, the new fuel charging pipe 4 and the return gas pipe 2, so as to help purge the bridging at the connection between the new fuel charging pipe 4 and the core main cycle unloading pipe 7.

[0054] Optionally, the outlet of the helium compressor is connected to a main pipeline and a bypass pipeline. The main pipeline is used to connect to the main circulation boost pipeline, and the bypass pipeline is used to connect to the inlet pipe 1.

[0055] Optionally, the main pipeline can be shut off and the bypass pipeline can be opened before the blockage upstream of the flow restrictor is resolved.

[0056] In the above implementation, the bypass pipeline is opened by the bypass valve on the bypass pipeline, and all the lifting gas supply valves on the main pipeline used to lift the fuel balls in the main circulation lifting pipeline are closed, so as to ensure that the airflow of all helium compressors is used for purging and blockage removal, thereby improving the efficiency of solving the upstream blockage of the flow restrictor in the fuel loading and unloading system of the high-temperature gas-cooled reactor.

[0057] Optionally, an intake electric valve 12 is provided on the intake pipe 1. The intake electric valve 12 can easily and quickly control the opening or closing of the intake pipe 1, making the operation very simple.

[0058] Optionally, the helium compressor is equipped with a main gas supply valve;

[0059] When resolving the blockage upstream of the flow restrictor, first open the main air supply valve, and then open the intake electric valve 12.

[0060] In the above embodiment, the main gas supply valve for purging is opened first, then the inlet electric valve 12 for reverse purging of the ring choke 3 is opened, and finally, the return gas valve 11 and the return gas valve of the corresponding helium compressor are opened to ensure that the purging circuit is in a closed state.

[0061] For example, the purging flow rate is increased by adjusting the speed of the helium compressor until the blockage at the bridging point is successfully resolved. After purging, a ball test can be performed using the operation of the flow deflector 3 to verify whether there is a blockage upstream of the flow deflector. If a fuel ball is confirmed to be falling at the flow deflector 3, it indicates that the blockage upstream of the flow deflector has been successfully resolved.

[0062] Optionally, during the purging process of the bridging at the connection between the helium generated by the helium compressor and the connection between the new fuel loading pipeline 4 and the core main circulation unloading pipeline 7, a listening device is used to judge the disturbance of the fuel ball in the bridging. When the collision sound of the fuel ball and the pipeline is heard, the purging is stopped.

[0063] In the above implementation, when a loud collision sound is heard between the fuel ball and the pipeline, the flow restrictor 3 can be activated to verify whether there is a blockage upstream of the flow restrictor.

[0064] In the embodiments of this application, the method for resolving upstream blockage of the flow restrictor in the fuel loading and unloading system of a high-temperature gas-cooled reactor has been verified when blockage occurred in a high-temperature gas-cooled reactor demonstration project. It can achieve online pneumatic unblocking, avoid the shutdown of the fuel loading and unloading system, and reduce the radiation dose received by personnel during maintenance work.

[0065] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled 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 method for resolving upstream blockage of a flow restrictor in a high-temperature gas-cooled reactor fuel loading and unloading system, characterized in that, Includes the following steps: Step S100: Establish a purging branch, which includes an inlet pipe and a return pipe; the inlet pipe is connected to the outlet of the helium compressor and to a flow restrictor; the return pipe is connected to the new fuel charging line and to the return port of the helium compressor; the outlet of the helium compressor is connected to a main pipeline and a bypass pipeline, the main pipeline being used to connect to the main circulation booster pipeline; the bypass pipeline being used to connect to the inlet pipe. Step S200: Close the first isolation valve on the main circulation unloading pipeline of the reactor core near the primary loop; wherein, the first isolation valve is used to control the on / off state between the primary loop and the main circulation unloading pipeline of the reactor core. Step S300: Open the second isolation valve on the new fuel charging pipeline, and the air inlet pipe, flow restrictor, connection between the new fuel charging pipeline and the core main circulation unloading pipeline, the new fuel charging pipeline, and the return gas pipe can form a passage. Before resolving the blockage upstream of the flow restrictor, shut off the main pipeline and open the bypass pipeline; In step S400, the helium generated by the helium compressor passes through the inlet pipe and the flow barrier in sequence and enters the connection between the new fuel charging pipeline and the core main circulation unloading pipeline to purge the bridging and resolve the blockage upstream of the flow barrier. During the purging of the bridging at the connection point between the helium compressor-generated helium entering the new fuel loading pipeline and the core main circulation unloading pipeline, a listening device is used to judge the disturbance of the fuel balls in the bridging. When the collision sound of the fuel balls hitting the pipeline is heard, the purging is stopped.

2. The method for resolving upstream blockage of the flow restrictor in a high-temperature gas-cooled reactor fuel loading and unloading system according to claim 1, characterized in that, The new fuel loading pipeline is connected to the new fuel temporary storage device, and the connection point between the return gas pipe and the new fuel loading pipeline is located between the new fuel temporary storage device and the second isolation valve.

3. The method for resolving upstream blockage of the flow restrictor in a high-temperature gas-cooled reactor fuel loading and unloading system according to claim 1, characterized in that, Before resolving the blockage upstream of the flow stopper, empty the fuel ball downstream of the flow stopper.

4. The method for resolving upstream blockage of the flow restrictor in a high-temperature gas-cooled reactor fuel loading and unloading system according to claim 1, characterized in that, A pellet separator and a distributor are sequentially installed on the main circulation unloading pipeline of the reactor core; the first isolation valve is located between the primary loop and the pellet separator.

5. The method for resolving upstream blockage of the flow restrictor in a high-temperature gas-cooled reactor fuel loading and unloading system according to claim 1, characterized in that, A return valve is installed on the return pipe; The return air valve is used to control the opening or closing of the return air pipe; When resolving the blockage upstream of the flow restrictor, the return gas valve is in the open state to form a passage between the inlet pipe, the flow restrictor, the connection between the new fuel charging line and the core main circulation unloading line, the new fuel charging line, and the return gas pipe.

6. The method for resolving upstream blockage of the flow restrictor in a high-temperature gas-cooled reactor fuel loading and unloading system according to claim 1, characterized in that, An electric intake valve is installed on the intake pipe.

7. The method for resolving upstream blockage of the flow restrictor in a high-temperature gas-cooled reactor fuel loading and unloading system according to claim 6, characterized in that, The helium compressor is equipped with a main gas supply valve; When resolving the blockage upstream of the flow restrictor, first open the main air supply valve, and then open the aforementioned electric air intake valve.

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