Method for loading reactor fuel assemblies and method for loading lead-bismuth stacks

Abstract

The embodiment of the invention relates to the field of reactor fuel elements and assembly thereof, in particular to a loading method of a reactor fuel assembly and a loading method of a lead-bismuth reactor. The loading method of the fuel assembly comprises the following steps: S10, a reactor body is installed, a neutron source assembly and a simulation assembly are loaded into preset positions, the fuel assembly is transported to a loading site, a reactivity control system, a nuclear measurement instrument and a special loading tool are debugged, and an experimenter is ready; s20, the control rod is inserted into the reactor core, and the reading of the nuclear measurement instrument is read and recorded; s30, operating the special loading tool, taking out the simulation assembly at the preset position, and putting the fuel assembly into the simulation assembly; s40, the step S30 is repeated until loading of a preset number of fuel assemblies is completed, and the reading of the nuclear measurement instrument is read and recorded; and S50, the steps S30-S40 are repeated, and loading of all the fuel assemblies is completed. The method for loading the fuel assembly of the reactor provided by the embodiment of the invention is beneficial to ensuring that the reactor safely reaches the full load of the fuel assembly.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of reactor fuel elements and their assembly, and specifically to a method for loading a reactor fuel assembly and a method for loading a lead-bismuth pile. Background Art

[0002] The statements herein merely provide background information related to the present application and do not necessarily constitute prior art.

[0003] The lead-cooled fast reactor (LFR) uses lead or lead-bismuth alloy as coolant, has excellent neutron physics, thermal hydraulics, and system safety properties, and has the advantages of high resource utilization, good safety, and good economy, and has broad application prospects.

[0004] The lead-bismuth reactor usually includes a reactor core and a fuel assembly. When assembling the lead-bismuth reactor, the fuel assembly needs to be loaded into a predetermined position of the reactor core. However, since the characteristics of the lead-bismuth reactor are different from those of other reactors, the existing method of loading the fuel assembly of the reactor is not fully applicable to the loading of the fuel assembly of the lead-bismuth reactor. Summary of the invention

[0005] A brief overview of the present application is provided below in order to provide a basic understanding of certain aspects of the present application. It should be understood that this overview is not an exhaustive overview of the present application. It is not intended to identify the key or important parts of the present application, nor is it intended to limit the scope of the present application. Its purpose is merely to present certain concepts in a simplified form as a prelude to a more detailed description discussed later.

[0006] In response to the above problems, embodiments of the present application provide a method for loading a reactor fuel assembly and a method for loading a lead-bismuth stack.

[0007] In the first aspect, an embodiment of the present application provides a method for loading a reactor fuel assembly, which includes the following steps: S10: the reactor body is installed and the neutron source assembly and the simulation assembly of the reactor have been loaded into the predetermined position of the reactor core, the reactivity control system of the reactor has been debugged and controlled normally, the fuel assembly has been transported to the site where the reactor body is loaded, the nuclear measurement instrument has been debugged, the special loading tool has been debugged, and the experimenter is ready; S20: the control rod of the reactor is inserted into the core, and the experimenter reads the indication of the nuclear measurement instrument and records it; S30: the experimenter operates the special loading tool to take out the simulation assembly at the predetermined position of the reactor core, and puts the fuel assembly into the position where the simulation assembly is located; S40: repeat step S30 until the loading of the predetermined number of fuel assemblies is completed, and the experimenter reads the indication of the nuclear measurement instrument and records it; S50: repeat steps S30-S40 until all fuel assemblies are loaded.

[0008] The method for loading the reactor fuel assemblies provided in the embodiments of the present application can load all the fuel assemblies into the core in batches, and can use nuclear testing instruments to detect the entire loading process of the fuel assemblies, which is beneficial to ensuring that the loading process of the fuel assemblies is safe and reliable, and further helps to ensure that the reactor safely reaches full load of fuel assemblies.

[0009] In a second aspect, an embodiment of the present application provides a method for loading a lead-bismuth stack, which comprises the following steps: completing the loading of the fuel assembly of the lead-bismuth stack using the method provided in the embodiment of the first aspect of the present application; and filling the lead-bismuth stack with the loaded fuel assembly with coolant.

[0010] The method for loading the lead-bismuth pile provided in the embodiment of the present application can separate the fuel loading process and the coolant filling process by first loading the fuel assembly of the lead-bismuth pile and then filling the coolant into the lead-bismuth pile with the loaded fuel assembly, which is beneficial to the safe assembly of the lead-bismuth pile and the improvement of assembly efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Other objects and advantages of the present application will become apparent from the following description of the embodiments of the present application with reference to the accompanying drawings, and will help to provide a comprehensive understanding of the present application.

[0012] Figure 1 It is a schematic flow chart of a method for loading a fuel assembly of a reactor provided in an embodiment of the present application.

[0013] Figure 2 It is a schematic flow chart of the method for loading a lead-bismuth pile provided in an embodiment of the present application.

[0014] It should be noted that the drawings are not necessarily drawn to scale, but are merely shown in a schematic manner that does not affect the reader's understanding. DETAILED DESCRIPTION

[0015] Exemplary embodiments of the present application will be described below in conjunction with the accompanying drawings. For the sake of clarity and conciseness, not all features of the actual implementation are described in the specification. However, it should be understood that many implementation-specific decisions must be made in the process of developing any such actual implementation in order to achieve the developer's specific goals, such as meeting those constraints related to the system and business, and these constraints may vary from implementation to implementation. In addition, it should be understood that although the development work may be very complex and time-consuming, it is only a routine task for those skilled in the art who benefit from the content of this application.

[0016] It is also necessary to explain here that, in order to avoid obscuring the present application due to unnecessary details, only the device structure and / or processing steps closely related to the scheme according to the present application are shown in the accompanying drawings, while other details that are not very relevant to the present application are omitted.

[0017] In the related art, when loading fuel assemblies into a reactor, the reactor is usually inspected at the beginning and after loading, but inspections are rarely performed during the loading process of the fuel assemblies, resulting in certain safety hazards during the loading process of the fuel assemblies.

[0018] In response to the above problems, embodiments of the present application provide a method for loading a reactor fuel assembly and a method for loading a lead-bismuth stack.

[0019] See also Figure 1 , Figure 1 It is a flow chart of a method for loading a reactor fuel assembly provided in an embodiment of the present application. The method for loading a reactor fuel assembly provided in an embodiment of the present application may include the following steps: S10: the reactor body is installed and the neutron source assembly and the simulation assembly of the reactor have been loaded into the predetermined position of the reactor core, the reactivity control system of the reactor is debugged and controlled normally, the fuel assembly has been transported to the site where the reactor body is loaded, the nuclear measurement instrument has been debugged, the special loading tool has been debugged, and the experimenter is ready; S20: the control rod of the reactor is inserted into the core, and the experimenter reads the indication of the nuclear measurement instrument and records it; S30: the experimenter operates the special loading tool to take out the simulation assembly at the predetermined position of the reactor core, and puts the fuel assembly into the position where the simulation assembly is located; S40: repeat step S30 until the loading of the predetermined number of fuel assemblies is completed, and the experimenter reads the indication of the nuclear measurement instrument and records it; S50: repeat steps S30-S40 until all fuel assemblies are loaded.

[0020] The method for loading the reactor fuel assemblies provided in the embodiments of the present application can load all the fuel assemblies into the core in batches, and can use nuclear testing instruments to detect the entire loading process of the fuel assemblies, which is beneficial to ensuring that the loading process of the fuel assemblies is safe and reliable, and further helps to ensure that the reactor safely reaches full load of fuel assemblies.

[0021] In some embodiments, the method for loading fuel assemblies for a reactor provided by the embodiments of the present application can be used for loading fuel assemblies for a megawatt-class lead-bismuth reactor.

[0022] In some embodiments, the fuel assemblies and other components within the core may be inspected prior to loading the fuel assemblies.

[0023] In some embodiments, the core can be divided into an inner ring and an outer ring according to the enrichment degree of the fuel assembly, the inner ring of the fuel assembly has a high enrichment degree, and the outer ring of the fuel assembly has a low enrichment degree. In some embodiments, in step S30, the fuel assemblies are loaded in the order from the inner ring of the core to the outer ring of the core. In such an embodiment, the fuel assemblies are loaded in the order from the inner ring of the core to the outer ring of the core, so that the loading of the fuel assemblies in the area with a high enrichment degree can be completed first, and then the loading of the fuel assemblies in the area with a low enrichment degree can be carried out, which is conducive to ensuring the safety and reliability of the loading process of the fuel assemblies.

[0024] In some embodiments, in step S30, during the process of loading the fuel assemblies in circles, the fuel assemblies are loaded into the symmetrical positions of each circle one by one. In such an embodiment, the above arrangement enables uniform loading of the fuel assemblies of the reactor, which is beneficial to ensuring the safety of the reactor.

[0025] In some embodiments, in step S30, when loading the fuel assembly into the core, the fuel with high value is loaded first, and then the fuel with low value is loaded. In such an embodiment, the fuel assembly is loaded in the order from the inner ring of the core to the outer ring of the core, so that the fuel with high value can be loaded first, and then the fuel with low value can be loaded, which is conducive to ensuring the safety and reliability of the loading process of the fuel assembly.

[0026] In some embodiments, in step S10, two monitoring systems are respectively provided, and the two monitoring systems are provided to be independent of each other. In such an embodiment, by providing two monitoring systems, it is beneficial to expand the monitoring scope to ensure that the entire loading process of the fuel assembly is under the monitoring of the monitoring system; at the same time, the two independent monitoring systems ensure that when one monitoring system fails, the other monitoring system can still work normally without completely failing.

[0027] In some embodiments, the monitoring system may be a neutron counting device, which can monitor and record the neutron counting rate. In some embodiments, two monitoring systems may be installed on the right side of the core, and the heights of the two monitoring systems are aligned with the plane where the fuel active area of ​​the core is located, so that the neutrons emitted by the neutron source can reach the monitoring system after passing through the entire core. In some embodiments, when the core size of the reactor is small, the neutron counting device may be 3 He counter tube or BF3 counter tube.

[0028] In some embodiments, during the loading process of the fuel assembly, the nuclear measurement instrument should avoid monitoring blind spots, that is, during the loading process in the fuel assembly, the neutron count rate measured by the monitoring system should be greater than or equal to 2cps.

[0029] In some embodiments, in step S10, the neutron source of the reactor is installed at the center of the neutron source assembly. Since the inherent neutron radiation level of the fuel assembly of the core is low, in order to meet the core monitoring requirements during the loading process, it is necessary to set the neutron source assembly in the core. In order to enable the neutron source assembly to be used for a long time during the operation of the reactor, the position setting of the neutron source needs to be considered when setting the neutron source assembly. The embodiments of the present application, by installing the neutron source at the center of the neutron source assembly, are conducive to meeting the core monitoring requirements for startup after shutdown throughout the life cycle.

[0030] In some embodiments, in step S10, the height of the neutron source is set to be aligned with the plane where the fuel active area of ​​the reactor is located. In such an embodiment, the neutron source arranged to be aligned with the plane where the fuel active area of ​​the reactor is located is also conducive to meeting the core monitoring requirements for startup after shutdown throughout the life cycle.

[0031] See also Figure 2 , Figure 2 It is a flow chart of the method for loading a lead-bismuth pile provided in an embodiment of the present application. The method for loading a lead-bismuth pile provided in an embodiment of the present application may include the following steps: S101, using the method for loading reactor fuel assemblies provided in any embodiment of the present application to complete the loading of fuel assemblies of the lead-bismuth pile; S102, filling coolant into the lead-bismuth pile with the loaded fuel assemblies.

[0032] The method for loading the lead-bismuth pile provided in the embodiment of the present application can separate the fuel loading process and the coolant filling process by first loading the fuel assembly of the lead-bismuth pile and then filling the coolant into the lead-bismuth pile with the loaded fuel assembly, which is beneficial to the safe assembly of the lead-bismuth pile and the improvement of assembly efficiency.

[0033] In some embodiments, the lead-bismuth stack uses UO2 fuel. Since the lead-bismuth stack has a long operating life, the embodiments of the present application use UO2 fuel to meet the needs of long-term operation of the lead-bismuth stack.

[0034] In some embodiments, the lead-bismuth reactor uses an isotope neutron source with a longer half-life. In order to enable the neutron source assembly to be used for a long time during the operation of the reactor, the type of neutron source needs to be considered when setting the neutron source assembly. The embodiments of the present application, by using an isotope neutron source with a longer half-life, are conducive to meeting the core monitoring requirements for startup after shutdown throughout the life cycle.

[0035] Regarding the embodiments of the present application, it should also be noted that, in the absence of conflict, the embodiments of the present application and the features therein can be combined with each other to obtain new embodiments.

[0036] The above are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. The protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for loading a reactor fuel assembly, characterized in that: It includes the following steps: S10: The reactor body is installed, the neutron source assembly and the simulation assembly of the reactor are loaded into the predetermined position of the reactor core, the reactivity control system of the reactor is debugged and controlled normally, the fuel assembly has been transported to the site where the reactor body is loaded, the nuclear measurement instrument has been debugged, the loading special tool has been debugged, and the experimenter is ready; S20: inserting the control rod of the reactor into the core, and the experimenter reads and records the indication of the nuclear measuring instrument; S30: the experimenter operates the special loading tool to take out the simulation component at a predetermined position of the core of the reactor, and puts the fuel assembly at the position where the simulation component is located; S40: Repeat step S30 until the predetermined number of fuel assemblies are loaded, and the experimenter reads and records the number displayed on the nuclear test instrument; S50: Repeat steps S30-S40 until all the fuel assemblies are loaded.

2. The method according to claim 1, characterized in that In step S30, the fuel assemblies are loaded in order from the inner circle of the core to the outer circle of the core.

3. The method according to claim 2, characterized in that In step S30, during the process of loading the fuel assemblies in circles, the fuel assemblies are loaded into the symmetrical positions of each circle one by one.

4. The method according to claim 1, characterized in that In step S30, when the fuel assembly is loaded into the core, the fuel with high value is loaded first, and then the fuel with low value is loaded.

5. The method according to any one of claims 1 to 4, characterized in that: In step S10, two monitoring systems are respectively set up, and the two monitoring systems are set up to be independent of each other.

6. The method according to claim 1, characterized in that In step S10, the neutron source of the reactor is installed at the center of the neutron source assembly.

7. The method according to claim 6, characterized in that In step S10, the height of the neutron source is set to be aligned with the plane where the fuel active area of ​​the reactor is located.

8. A method for loading a lead-bismuth pile, characterized in that: It includes the following steps: The method according to any one of claims 1 to 7 is used to complete the loading of the fuel assembly of the lead-bismuth stack; The lead-bismuth pile loaded with the completed fuel assembly is filled with coolant.

9. The method according to claim 8, characterized in that The lead-bismuth stack uses UO2 fuel.

10. The method according to claim 8 or 9, characterized in that: The lead-bismuth pile adopts an isotope neutron source with a relatively long half-life.

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