Method for loading of a reactor fuel assembly and method for loading of a lead bismuth reactor

Abstract

The embodiment of the application relates to the field of reactor fuel elements and assembly thereof, in particular to a method for loading a reactor fuel assembly and a method for loading a lead-bismuth reactor. The method for loading the fuel assembly comprises the following steps: S10, reactor body installation is completed, a neutron source assembly and a simulation assembly are loaded into predetermined positions, a fuel assembly is transported to a loading site, a reactivity control system, nuclear measuring instruments and loading special tools are debugged, and experimental personnel are prepared; S20, a control rod is inserted into a reactor core, a reading of the nuclear measuring instruments is taken and recorded; S30, the loading special tools are operated, the simulation assembly in the predetermined position is taken out and placed into the fuel assembly; S40, the step S30 is repeated until loading of a predetermined number of fuel assemblies is completed, a reading of the nuclear measuring instruments is taken and recorded; and S50, the steps S30-S40 are repeated to complete loading of all fuel assemblies. The method for loading the fuel assembly of the reactor provided by the embodiment of the application is beneficial to ensuring that the reactor is safely loaded with the fuel assembly.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the field of reactor fuel elements and their assembly, in particular to a method for loading a reactor fuel assembly and a method for loading a lead-bismuth reactor. BACKGROUND

[0002] The statements herein are merely provided to give general background information on the present application, and do not necessarily constitute the prior art.

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

[0004] A lead-bismuth reactor generally 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, due to the different characteristics of the lead-bismuth reactor from other reactors, the existing method for loading the fuel assembly of the reactor cannot be completely applied to the loading of the fuel assembly of the lead-bismuth reactor. SUMMARY

[0005] In the following, a brief overview of the present application is given to provide a basic understanding of some aspects of the present application. It should be understood that this overview is not an extensive overview of the present application. It is not intended to identify 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 some concepts in a simplified form as a prelude to the more detailed description of a later discussion.

[0006] To solve 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 reactor.

[0007] In a first aspect, embodiments of the present application provide a method for loading a reactor fuel assembly, which includes the following steps: S10: the reactor body is installed and complete, the neutron source assembly and the simulation assembly of the reactor have been loaded into the predetermined position of the core of the reactor, the reactivity control system of the reactor has been debugged and controlled normally, the fuel assembly has arrived at the site set by the reactor body for loading, the nuclear measuring instrument has been debugged and completed, the loading special tool has been debugged and completed, and the experimental personnel have been prepared; S20: the control rod of the reactor is inserted into the core, and the experimental personnel read the display number of the nuclear measuring instrument and record it; S30: the experimental personnel operate the loading special tool, take out the simulation assembly at the predetermined position of the core of the reactor, and place the fuel assembly at the position where the simulation assembly is located; S40: repeat the step S30 until the loading of the predetermined number of fuel assemblies is completed, and the experimental personnel read the display number of the nuclear measuring instrument and record it; S50: repeat the steps S30-S40 until the loading of all fuel assemblies is completed.

[0008] The method for loading fuel assemblies of a reactor provided by the embodiments of the present application can load all fuel assemblies into the reactor core in batches, and can detect the whole loading process of the fuel assemblies by using nuclear measuring instruments, which is beneficial to ensure the safety and reliability of the loading process of the fuel assemblies, and further beneficial to ensure that the reactor safely reaches full load of the fuel assemblies.

[0009] In a second aspect, the embodiments of the present application provide a method for loading a lead-bismuth reactor, which comprises the following steps: loading fuel assemblies of the lead-bismuth reactor by using the method provided by the embodiments of the first aspect of the present application; and filling the lead-bismuth reactor loaded with the fuel assemblies with a coolant.

[0010] The method for loading a lead-bismuth reactor provided by the embodiments of the present application can separate the fuel loading process and the coolant filling process by first loading the fuel assemblies of the lead-bismuth reactor and then filling the lead-bismuth reactor loaded with the fuel assemblies with a coolant, which is beneficial to the safe assembly of the lead-bismuth reactor and to improving the assembly efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0011] Other objects and advantages of the application can be more fully understood from the following description of the embodiments of the present application taken in conjunction with the accompanying drawings.

[0012] Figure 1 FIG. 1 is a flowchart of a method for loading fuel assemblies of a reactor provided by an embodiment of the present application.

[0013] Figure 2 FIG. 2 is a flowchart of a method for loading a lead-bismuth reactor provided by an embodiment of the present application.

[0014] It should be noted that the accompanying drawings are not necessarily drawn to scale, but are merely intended to illustrate the illustrative aspects of the present application. DETAILED DESCRIPTION

[0015] The exemplary embodiments of the present application will be described hereinafter with reference to the accompanying drawings. In the description, all features that are possible to implement in the actual embodiments are not described in the specification for the sake of clarity and conciseness. It should be appreciated, however, that many implementation-specific decisions can have to be made in order to develop any such actual embodiments, to implement developer-specific goals, such as compliance with system- and business-related constraints, which will vary from one implementation to another. It should also be appreciated that such a development effort might arguably be more complex and time-consuming than the actual implementation of the application itself.

[0016] It should be noted that, in order not to obscure the application with unnecessary details, only the device structure and / or processing steps closely related to the scheme according to the application are shown in the drawings, and other details not closely related to the application are omitted.

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

[0018] To solve the above problems, the embodiments of the application provide a method for loading fuel assemblies of a reactor and a method for loading a lead-bismuth reactor.

[0019] Referring to Figure 1 , Figure 1 is a flowchart of the method for loading fuel assemblies of a reactor provided by the embodiments of the application. The method for loading fuel assemblies of a reactor provided by the embodiments of the application can include 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 controlled normally after debugging, the fuel assemblies have arrived at the site where the reactor body is arranged, the nuclear measuring instrument has been debugged, the loading special tool has been debugged, and the experiment personnel are ready; S20: the control rod of the reactor is inserted into the core, and the experiment personnel read the display number of the nuclear measuring instrument and record it; S30: the experiment personnel operate the loading special tool, take out the simulation assembly at the predetermined position of the reactor core, and place the fuel assembly at the position where the simulation assembly is located; S40: repeat the step S30 until the loading of the predetermined number of fuel assemblies is completed, and the experiment personnel read the display number of the nuclear measuring instrument and record it; S50: repeat the steps S30-S40 until the loading of all fuel assemblies is completed.

[0020] The method for loading fuel assemblies of a reactor provided by the embodiments of the application can load all fuel assemblies into the core in batches, and can detect the entire loading process of the fuel assemblies by using the nuclear measuring instrument, which is beneficial to ensure the safety and reliability of the loading process of the fuel assemblies, and further beneficial to ensure that the reactor safely reaches the full load of the fuel assemblies.

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

[0022] In some embodiments, before loading the fuel assemblies, the fuel assemblies and other assemblies in the core can be inspected.

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

[0024] In some embodiments, in the step S30, in the process of loading the fuel assemblies one circle at a time, the fuel assemblies are loaded in each circle in symmetrical positions in turn. In such embodiments, the above arrangement enables uniform loading of the fuel assemblies of the reactor to be achieved, which is conducive to ensuring the safety of the reactor.

[0025] In some embodiments, in the step S30, when loading the fuel assemblies into the core, the fuel with a high value is loaded first, and then the fuel with a low value is loaded. In such embodiments, loading in order from the inner circle of the core to the outer circle of the core enables the fuel with a high value to be loaded first, and then the fuel with a low value to be loaded, which is conducive to ensuring the safety and reliability of the loading process of the fuel assemblies.

[0026] In some embodiments, in the step S10, two sets of monitoring systems are respectively provided, and the two sets of monitoring systems are provided independently of each other. In such embodiments, by providing two sets of monitoring systems, it is possible to expand the monitoring range to ensure that the entire loading process of the fuel assemblies is under the monitoring of the monitoring systems; at the same time, the two sets of monitoring systems being independent of each other means that when one set of monitoring systems fails, the other set of monitoring systems can still work normally and is not completely disabled.

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

[0028] In some embodiments, during the loading process of the fuel assemblies, the nuclear measuring instrument should avoid having a monitoring blind area, i.e., the neutron count rate measured by the monitoring system during the loading process of the fuel assemblies should be greater than or equal to 2 cps.

[0029] In some embodiments, in the step S10, the neutron source of the reactor is installed at a central position of the neutron source assembly. Due to the low inherent neutron radiation level of the fuel assemblies of the reactor core, the neutron source assembly needs to be arranged in the reactor core to meet the requirement of core monitoring during the loading process. In order to enable the neutron source assembly to be used for a long time during the operation of the reactor, the position of the neutron source needs to be considered when the neutron source assembly is arranged. In the embodiments of the present application, the neutron source is installed at the central position of the neutron source assembly, which is beneficial to meet the requirement of core monitoring after shutdown and startup during the whole service life.

[0030] In some embodiments, in the step S10, the height of the neutron source is arranged to be aligned with the plane where the fuel active region of the reactor is located. In such embodiments, the neutron source arranged to be aligned with the plane where the fuel active region of the reactor is located is also beneficial to meet the requirement of core monitoring after shutdown and startup during the whole service life.

[0031] Referring to Figure 2 , Figure 2 is a flowchart of the method for loading the lead-bismuth reactor provided by the embodiments of the present application. The method for loading the lead-bismuth reactor provided by the embodiments of the present application can include the following steps: S101, loading the fuel assemblies of the lead-bismuth reactor by using the method for loading the reactor fuel assemblies provided by any of the embodiments of the present application; S102, filling the coolant into the lead-bismuth reactor whose fuel assemblies are loaded.

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

[0033] In some embodiments, the lead-bismuth reactor uses UO2 fuel. Since the lead-bismuth reactor has a long service life, the embodiments of the present application use UO2 fuel, which is beneficial to meet the requirement of long-term operation of the lead-bismuth reactor.

[0034] In some embodiments, the lead-bismuth reactor uses isotopic neutron sources with a long 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 the neutron source also needs to be considered when the neutron source assembly is arranged. In the embodiments of the present application, the isotopic neutron sources with a long half-life are used, which is beneficial to meet the requirement of core monitoring after shutdown and startup during the whole service life.

[0035] It should be further noted that the embodiments of the present application and the features in the embodiments can be combined with each other to obtain new embodiments without conflict.

[0036] The above merely illustrates the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method of loading a reactor fuel assembly, characterized by, It comprises the following steps: S10: the reactor body installation is completed, the neutron source assembly and the simulation assembly of the reactor are loaded into the predetermined position of the core of the reactor, the reactivity control system of the reactor is debugged to be normal, the fuel assembly has arrived at the site where the reactor body is installed, the nuclear measuring instrument has been debugged, the loading special tool has been debugged, and the experimental personnel are ready; S20: the control rod of the reactor is inserted into the core, and the experimental personnel read the display number of the nuclear measuring instrument and record it; S30: the experimental personnel operate the loading special tool, take out the simulation assembly at the predetermined position of the core of the reactor, and put the fuel assembly at the position where the simulation assembly is located; S40: repeat the step S30 until the loading of the predetermined number of fuel assemblies is completed, and the experimental personnel read the display number of the nuclear measuring instrument and record it; S50: repeat the steps S30-S40 until the loading of all the fuel assemblies is completed; In the step S30, the fuel assemblies are loaded in order from the inner ring of the core to the outer ring of the core; In the step S30, during the loading of the fuel assemblies one by one, the fuel assemblies are loaded in the symmetrical positions of each ring in turn; In the step S30, when loading the fuel assemblies into the core, the fuel with high value is loaded first, and then the fuel with low value is loaded.

2. The method according to claim 1, wherein, In the step S10, two sets of monitoring systems are respectively arranged, and the two sets of monitoring systems are arranged independently.

3. The method according to claim 1, wherein, In the step S10, the neutron source of the reactor is installed at the center position of the neutron source assembly.

4. The method according to claim 3, wherein, In the step S10, the height of the neutron source is arranged to be aligned with the plane where the fuel active area of the reactor is located.

5. A method of loading a lead bismuth pile, characterized in that, It comprises the following steps: The loading of the fuel assembly of the lead-bismuth reactor is completed by using the method according to any one of claims 1-4; The coolant is filled into the lead-bismuth reactor where the loading of the fuel assembly is completed.

6. The method according to claim 5, wherein, The lead-bismuth reactor uses UO2 fuel.

7. The method according to claim 5 or 6, wherein, The lead-bismuth reactor uses the isotope neutron source with long half-life.

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