Fuel assembly irradiation test method based on high-temperature and high-pressure test loop

Abstract

A fuel assembly irradiation test method based on a high-temperature and high-pressure test loop relates to the technical field of research of reactor fuel irradiation, and comprises the steps of determining technical index parameters of fuel assembly irradiation test, designing a preliminary scheme of an irradiation test system, performing safety analysis on the scheme under accident conditions, and simulating an in-reactor irradiation test. On the basis of safety analysis and test results, reactor-out time and operation states of the device and the system are determined, and finally whether simulation operation of a fuel assembly in a reactor core in a research reactor meets technical index requirements or not is judged according to the reactor-out time and operation state data; according to the method, a set of systematized and standardized process is provided, and each process from determination of technical index parameters to final generation of an irradiation test system has clear requirements and standards, so that the working efficiency is favorably improved, human errors are reduced, and subsequent verification and improvement are facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of research reactor fuel irradiation, and in particular to a fuel assembly irradiation test method based on a high-temperature and high-pressure test loop. Background Art

[0002] Fuel irradiation test technology refers to the use of neutrons and various rays produced by research reactors to design and build test systems, control and adjust the irradiation conditions of test pieces, and ensure that the test pieces can still receive safe irradiation as required under strong radiation conditions in the reactor. From the proposal of fuel concept design to the engineering application of fuel assemblies, in-pile irradiation tests must be carried out on key objects such as fuel and cladding materials to comprehensively evaluate the radiation resistance of the fuel, and then measure the safety, reliability, economy and advancement of the fuel assemblies.

[0003] In addition, steady-state irradiation tests of PWR fuel assemblies in research reactors are usually carried out in high-temperature and high-pressure water test loops, which are closed systems whose main loops are mainly composed of irradiation devices, pressurizers, main heat exchangers, and feedwater pumps. The irradiation device is used for irradiation tests, and the coolant parameters in the irradiation device, such as temperature, pressure, flow, and water quality, are all controlled separately by the irradiation test system. The heat released by the test piece and the structural parts in the irradiation test system is taken away by the coolant of the irradiation test system, and there is no heat exchange between the coolant and the main coolant of the research reactor.

[0004] In addition, the irradiation test of fuel assemblies not only involves the design of core loading, test loop system and irradiation device, but also involves the engineering implementation of loop system debugging, test operation and monitoring. It requires the cooperation of multiple professional technicians such as physics, thermal engineering, mechanics, materials, instrumentation and control, and electrical engineering to carry out the test plan design and irradiation test implementation. There are problems such as multiple design iterations and multiple implementation interfaces. And for different types of fuel assemblies, it is necessary to redesign the irradiation test system plan and then carry out the corresponding engineering implementation content.

[0005] A Chinese patent (CN201811339296.4) discloses a method for irradiation testing of domestic nuclear fuel assemblies before entering the reactor. This method improves the core design and is used to meet the requirements of the irradiation test of the refueling core of the 10th fuel cycle of Unit 2 of the Qinshan Second Nuclear Power Plant. However, this method lacks the corresponding design of the test device and the loop system. Therefore, there are still certain safety risks in the process of the core entering the reactor test.

[0006] Therefore, we propose a method that can provide a systematic optimization of the fuel assembly irradiation test process. Summary of the invention

[0007] In order to overcome the deficiencies in the background technology, the present invention discloses a fuel assembly irradiation test method based on a high temperature and high pressure test loop.

[0008] In order to achieve the above-mentioned invention object, the present invention adopts the following technical scheme:

[0009] A fuel assembly irradiation test method based on a high temperature and high pressure test loop, comprising:

[0010] S1. Determine the technical parameters of the fuel assembly irradiation test;

[0011] S2. Based on the technical index parameters, obtain the core loading plan, test component plan, test device plan, loop system operation plan, irradiation safety protection plan and quality assurance plan;

[0012] S3. Based on the design solution obtained in S2, perform safety analysis under accident conditions;

[0013] S4. If the safety analysis result is unsafe, return to S2 and redesign the solution;

[0014] S5. If the safety analysis result is safe, the test circuit is debugged based on the design scheme of S2;

[0015] S6. Combined with the safety analysis results of S3 and the results of the test loop commissioning of S5, conduct irradiation test of the fuel assembly, analyze the time of the fuel assembly to be removed from the reactor, and the operating status of the test device and loop system in the design scheme;

[0016] S7. Determine whether the fuel assembly in the core meets the technical index requirements in the simulated operation of the research reactor according to the operating status of the test device and the loop system;

[0017] S8. If not satisfied, return to S6 and continue the in-pile irradiation test;

[0018] S9. If the conditions are met, the fuel assembly is removed from the stack for cooling and inspection, the irradiation test of the fuel assembly is completed, and the irradiation test results are obtained.

[0019] Preferably, the determination of the technical indicator parameters includes the following:

[0020] S11. Confirm the technical index requirements of irradiation test, including power, fuel consumption, temperature, pressure and water chemical environment indicators;

[0021] S12. Design the preliminary framework of core loading, test equipment and cooling circuit according to the technical index requirements;

[0022] S13. Based on the preliminary framework of core loading, test equipment and cooling circuit, the feasibility and matching of technical indicator requirements are demonstrated to obtain the preliminary plan of core loading, test equipment and cooling circuit and determine the technical indicator parameters.

[0023] Preferably, in S13, the feasibility and matching demonstration of the technical indicator requirements is specifically as follows:

[0024] S131. Evaluate the neutron flux distribution and power density parameters in the core by calculation methods, and analyze the reactor thermal safety limits under different operating conditions;

[0025] S132. Determine the mechanical strength and thermal performance of the test device;

[0026] S133. Evaluate the flow control and pressure regulation capabilities of the cooling circuit under different operating conditions, as well as the interface compatibility with the core and the test device;

[0027] S134. Based on the results of S131, S132 and S133, conduct an overall matching analysis on the preliminary framework of core loading, test device and cooling circuit, and evaluate the feasibility of the preliminary framework of core loading, test device and cooling circuit.

[0028] Preferably, the design process of each solution in S2 is respectively:

[0029] The core loading scheme includes physical calculation methods, test core arrangement and test index parameter calculation results;

[0030] The component solution to be tested includes component structure parameters and interface requirements;

[0031] The test device solution includes the device structure design and the measurement point layout design;

[0032] The system operation plan includes subsystem design, interface requirements and operation program design;

[0033] Radiation safety and protection programmes include radiation protection management, radiation monitoring and radioactive waste management;

[0034] The quality assurance program includes controls on documents, designs, items and processes.

[0035] Preferably, the safety analysis of S3 includes core loading physical safety analysis, test device safety analysis, system safety analysis and accident safety analysis.

[0036] Preferably, the core loading physical safety analysis adopts reactor thermal safety limit analysis to analyze whether the safety limits meet the requirements under different operating conditions.

[0037] Preferably, the safety analysis of the test device includes device mechanical analysis and thermal analysis, which are used to analyze the structural strength and thermal-hydraulic characteristics of the test device under different working conditions.

[0038] Preferably, the system safety analysis adopts loop pipeline safety analysis to analyze whether the loop system pipeline strength meets the requirements under different working conditions.

[0039] Preferably, the accident safety analysis adopts a method combining probability theory and determinism to analyze the safety of systems and devices under accident conditions with multiple factors.

[0040] Preferably, the simulated stack irradiation test in S5 includes a stack test operation and cold and hot debugging, wherein the stack test operation is used to check whether there is structural interference between the test device and the research reactor body when the fuel assembly is loaded into the stack, and the rationality of the stack test operation; the cold and hot debugging is used to check the working status of the loop system and the test device, and record the operating data in the stack.

[0041] Due to the adoption of the above-mentioned technical solution, the present invention has the following beneficial effects:

[0042] The invention discloses a fuel assembly irradiation test method based on a high temperature and high pressure test loop. Based on the technical index parameters of irradiation tests of different fuel assemblies, a targeted irradiation test system can be quickly constructed for any fuel assembly to ensure the accuracy of the irradiation test results of the fuel assembly.

[0043] Furthermore, the present invention provides a set of systematic and standardized processes, from the determination of technical indicator parameters to the final generation of the irradiation test system, each of which has clear requirements and standards, thereby helping to improve work efficiency, reduce human errors, and facilitate subsequent verification and improvement;

[0044] And through the feedback mechanism in this method, the design scheme can be continuously optimized to achieve the purpose of gradually improving and optimizing the entire irradiation test system to ensure that all technical indicators are ultimately met;

[0045] In addition, detailed safety analysis can ensure the safety of the entire test process, and through detailed demonstration and design of technical indicator parameters, it can be ensured that the fuel assembly can operate stably under predetermined conditions, thereby improving the reliability and stability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 A schematic diagram of a process of the present invention;

[0047] Figure 2 It is a detailed schematic diagram of each in the present invention. DETAILED DESCRIPTION

[0048] The technical solution of the present invention will be described below in conjunction with the drawings in the embodiments of the present invention. In the description, it should be understood that if there are terms such as "upper", "lower", "front", "back", "left", "right" and the like indicating directions or positional relationships, they are only corresponding to the drawings of the present invention, for the convenience of describing the present invention, and do not indicate or imply that the devices or components referred to must have a specific direction:

[0049] Embodiment 1 is:

[0050] Combined with Figure 1 The fuel assembly irradiation test method based on a high temperature and high pressure test loop comprises:

[0051] S1. Determine the technical parameters of the fuel assembly irradiation test;

[0052] The irradiation index demonstration mainly includes two parts: confirmation of technical index requirements and key parameter analysis and demonstration. Technical index requirements generally include temperature, pressure, fuel consumption, water chemical environment, etc. The feasibility and matching of the indicators are demonstrated based on the core physics, test device, and loop system to obtain a preliminary plan and clear technical index parameters;

[0053] S2. Based on the technical index parameters, obtain the core loading plan, test component plan, test device plan, loop system operation plan, irradiation safety protection plan and quality assurance plan;

[0054] The various schemes designed constitute the preliminary overall scheme of the irradiation test system. Subsequent verification and testing are based on the preliminary overall scheme. If the verification results meet the requirements of the technical indicators, it can be determined that the design scheme meets the requirements of the research reactor operation.

[0055] S3. Based on the design scheme obtained in S2, safety analysis is performed under accident conditions to ensure safety during the entire test process;

[0056] S4. If the safety analysis result is unsafe, return to S2 and redesign the solution;

[0057] S5. If the safety analysis result is safe, then based on the design plan of S2, test loop debugging is carried out to ensure that the fuel assembly can operate stably under the predetermined conditions through detailed demonstration and design of technical index parameters, thereby improving the reliability and stability of the system;

[0058] S6. Combined with the safety analysis results of S3 and the results of the test loop commissioning of S5, conduct irradiation test of the fuel assembly, analyze the time of the fuel assembly to be removed from the reactor, and the operating status of the test device and loop system in the design scheme;

[0059] After obtaining the safety analysis results and the simulated reactor irradiation test results, the test operation and monitoring are carried out, including test index monitoring, test data recording, system sampling monitoring, and test tracking calculation. Test index monitoring mainly monitors the parameters of the device and loop system, and timely adjusts the loop flow, pressure, water quality and other parameters. Test data recording and tracking calculation are mainly based on the recorded parameters to complete the tracking calculation, and timely and effectively monitor the test process. System sampling monitoring is mainly based on the environmental requirements of irradiation test indicators such as water chemistry, and regularly samples and analyzes the irradiation test environment to indirectly monitor the technical status of the test components;

[0060] S7. Determine whether the fuel assembly in the core meets the technical index requirements in the simulated operation of the research reactor according to the operating status of the test device and the loop system;

[0061] Among them, by carefully analyzing the time of stacking out of the pile, the effectiveness and safety of the entire irradiation test process can be ensured, and reliable data support can be provided for the subsequent evaluation and application of the fuel assembly. Therefore, after obtaining the time of stacking out of the pile, as well as the operating status of the test device and the loop system, the stacking out cooling and testing are carried out. The stacking out cooling and testing include the test index evaluation, temporary storage cooling of the device, device transfer cutting and sorting, and irradiation test test results. The test index evaluation should be comprehensively evaluated based on the monitoring data and the calculated data, and the stacking out operation should be carried out after the irradiation test index requirements are met; the temporary storage cooling of the device should monitor the dose regularly, and the transfer cutting should be carried out after the dose requirements are met. The device transfer cutting should be carried out in accordance with the corresponding cutting procedure and process flow, and the sorting of the test components should be completed; the irradiation test test results should include the irradiation test process data and the post-irradiation inspection data;

[0062] By analyzing the time of the stack, it is possible to determine whether the irradiation time of the fuel assembly in the reactor has reached the expected irradiation degree, monitor the irradiation progress of the fuel assembly in the stack, ensure that the irradiation time of the fuel assembly in the stack will not exceed the safety limit, avoid damage to the fuel assembly or other safety hazards due to excessive irradiation, and help collect data on the behavior of the fuel assembly during the irradiation process, including changes in parameters such as temperature, pressure, and flow rate. It can also evaluate the effectiveness of the test plan. If some parameters or designs are found to be unreasonable, the test plan can be adjusted according to the analysis results to optimize the test conditions.

[0063] It should be noted that the operating environment of the research reactor is simulated through the cooperation of the test loop and the irradiation test.

[0064] S8. If not satisfied, return to S6 and continue the in-pile irradiation test;

[0065] S9. If the conditions are met, the fuel assembly is removed from the stack for cooling and inspection, the irradiation test of the fuel assembly is terminated, and the inspection result of the irradiation test is obtained;

[0066] The cooling and inspection of fuel assemblies after leaving the reactor mainly include test index evaluation, temporary storage cooling of the device, device transfer cutting and sorting, and irradiation test results.

[0067] The test index assessment is a comprehensive assessment based on monitoring data and calculation data, and the unloading operation is carried out after the irradiation test index requirements are met;

[0068] The device is temporarily cooled to monitor the dosage regularly, and the device is transported and cut after the dosage requirement is met;

[0069] The device transfer cutting should be carried out according to the corresponding cutting procedures and process flow, and the sorting of test components should be completed;

[0070] The irradiation test results include irradiation test process data and post-irradiation inspection data.

[0071] Embodiment 2:

[0072] The determination of the technical indicator parameters in S1 includes the following:

[0073] S11. Confirm the technical index requirements of irradiation test, including power, fuel consumption, temperature, pressure and water chemical environment indicators;

[0074] S12. Design the preliminary framework of core loading, test equipment and cooling circuit according to the technical index requirements;

[0075] S13. Based on the preliminary framework of core loading, test equipment and cooling circuit, the feasibility and matching of technical indicator requirements are demonstrated to obtain the preliminary plan of core loading, test equipment and cooling circuit and determine the technical indicator parameters.

[0076] In addition, the feasibility and matching demonstration of the technical indicator requirements in S13 is as follows:

[0077] S131. Evaluate the neutron flux distribution, power density and other parameters in the core by calculation methods, and analyze the reactor thermal safety limits under different operating conditions;

[0078] S132. Determine the mechanical strength and thermal performance of the test device;

[0079] S133. Evaluate the flow control and pressure regulation capabilities of the cooling circuit under different operating conditions, as well as the interface compatibility with the core and the test device;

[0080] S134. Based on the results of S131, S132 and S133, conduct an overall matching analysis on the preliminary framework of core loading, test device and cooling circuit, and evaluate the feasibility of the preliminary framework of core loading, test device and cooling circuit.

[0081] Embodiment 3:

[0082] The design processes of each solution in S2 are as follows:

[0083] The core loading scheme includes physical calculation methods, test core arrangement and test index parameter calculation results, and it should meet the test sample temperature, pressure and fuel consumption and other index requirements, while meeting the safety limit requirements;

[0084] The test component scheme includes component structural parameters and interface requirements, and it should consider the reasonable layout of components to meet the test indicators and heat exchange requirements;

[0085] The test device solution includes the device structure design and the measurement point layout design, and it should consider sufficient measurement parameters and reasonable layout of measurement points, and can cooperate with the loop system to achieve pressure matching and flow matching to meet the test indicators;

[0086] The system operation plan includes subsystem design, interface requirements and operation program design, and it should consider water chemical environment, loop measurement and flow control to meet test requirements, loop system-reactel key parameter transmission and safety signal linkage plan, and loop system response plan under accident conditions;

[0087] The radiation safety protection plan includes radiation protection management, radiation monitoring and radioactive waste treatment, and it should consider the radioactive monitoring and protection of the loop system, equipment, personnel, etc., and formulate emergency procedures, etc.;

[0088] The quality assurance plan includes controls on documents, designs, items and processes, and should take into account the quality of management and technical activities throughout the entire irradiation test cycle, including the management and control of the design, processing, commissioning, operation and maintenance of test components, test equipment, core loading, loop systems, etc., formulate quality plans, and form document records to ensure that the entire irradiation test cycle is under effective control.

[0089] Embodiment 4:

[0090] The safety analysis of S3 includes physical safety analysis of core loading, safety analysis of test equipment, system safety analysis and accident safety analysis.

[0091] The core loading physical safety analysis adopts the reactor thermal safety limit analysis, the purpose of which is to analyze whether the safety limit under different working conditions meets the requirements; the specific analysis process is: ① Steady-state analysis: Under normal operating conditions, calculate the temperature field, pressure field and flow distribution in the core to ensure that they are within the safety range;

[0092] ② Transient analysis: Consider various transient conditions (such as coolant loss, control rod insertion / extraction, etc.) and evaluate the core response under these conditions;

[0093] ③ Extreme operating condition analysis: Analysis of core performance under extreme operating conditions, such as maximum power output, maximum temperature, etc.;

[0094] The safety analysis of the test device includes mechanical analysis and thermal analysis of the device, the purpose of which is to analyze the structural strength and thermal hydraulic characteristics of the test device under different working conditions; the specific process of mechanical analysis is: using computational fluid dynamics (CFD) and heat conduction analysis to evaluate the stress distribution and deformation of the device under high temperature and high pressure environment, including static analysis: evaluating the stress and deformation of the device under static load; dynamic analysis: considering the influence of dynamic loads such as vibration and impact; fatigue analysis: evaluating the fatigue life of the device in long-term operation;

[0095] The specific process of thermal analysis is: using computational fluid dynamics (CFD) and heat conduction analysis to evaluate the temperature distribution and heat transfer efficiency in the device, including flow analysis: evaluating the flow state of the coolant in the device to ensure uniform cooling; heat transfer analysis: evaluating the heat transfer efficiency between the device and the coolant to ensure that the device will not overheat; thermal stress analysis: evaluating the thermal stress caused by temperature changes to ensure that the device will not be damaged by thermal stress;

[0096] The system safety analysis adopts loop pipeline and other safety analysis, the purpose of which is to analyze whether the strength of the loop system pipeline meets the requirements under different working conditions, and to ensure that the pipelines, pumps, valves and other components in the loop system have sufficient strength and reliability under various working conditions; specifically use the design standards of pressure vessels and pipelines (such as ASME specifications) to conduct structural strength and fatigue life analysis, including pressure analysis: evaluate the strength of pipelines and equipment under different pressure conditions; fluid dynamics analysis: evaluate the impact of coolant flow on pipelines and equipment; corrosion and wear analysis: evaluate the corrosion and wear of pipelines and equipment in long-term operation. The accident safety analysis adopts a method combining probability theory and determinism to analyze the safety of systems and devices under accident conditions with multiple factors.

[0097] The accident safety analysis adopts a method combining probability theory and determinism to analyze the safety of systems and devices under accident conditions with multiple factors; the evaluation steps of probabilistic risk assessment (PRA) include: event identification: identifying possible accident events and their causes, frequency assessment: evaluating the frequency of occurrence of each event, and consequence analysis: evaluating the potential consequences of each event.

[0098] The analysis steps of deterministic analysis include: fault tree analysis: construct a fault tree to analyze the various fault paths that lead to the accident, event tree analysis: construct an event tree to analyze the various possible development paths after the accident, and comprehensive evaluation: combine the results of probability theory and determinism to conduct a comprehensive risk assessment and formulate corresponding safety measures and emergency plans.

[0099] Embodiment 5:

[0100] The simulated stack irradiation test in S5 includes stack test operation and cold and hot commissioning. The stack test operation is used to check whether there is structural interference between the test device and the research reactor body when the fuel assembly is loaded into the stack, and the rationality of the stack test operation; the cold and hot commissioning is used to check the working status of the loop system and the test device, and record the operating data in the stack; in addition, the structural integrity of the fuel assembly before and after the fuel assembly is checked before and after loading.

[0101] In addition, from the perspective of stages, this method can also be divided into stage 1: irradiation index demonstration, corresponding to S1, stage 2: irradiation test plan design, corresponding to S2, stage 3: safety analysis and review, corresponding to S3-S4, stage 4: loop system and device commissioning, corresponding to S5, stage 5: test operation and detection, corresponding to S6, stage 6: cooling detection after leaving the reactor, corresponding to S7-S9, as shown in the attached Figure 2 shown.

[0102] The parts of the present invention that are not described in detail are prior art. It is obvious to those skilled in the art that the present invention is not limited to the details of the above-mentioned exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention; therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the appended claims rather than the above description. Therefore, it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the present invention, and any figure marks in the claims should not be regarded as limiting the claims involved.

Claims

1. A fuel assembly irradiation test method based on a high temperature and high pressure test loop, characterized by: include: S1. Determine the technical parameters of the fuel assembly irradiation test; S2. Based on the technical index parameters, obtain the core loading plan, test component plan, test device plan, loop system operation plan, irradiation safety protection plan and quality assurance plan; S3. Based on the design solution obtained in S2, perform safety analysis under accident conditions; S4. If the safety analysis result is unsafe, return to S2 and redesign the solution; S5. If the safety analysis result is safe, the test circuit is debugged based on the design scheme of S2; S6. Combined with the safety analysis results of S3 and the results of the test loop commissioning of S5, conduct irradiation test of the fuel assembly, analyze the time of the fuel assembly to be removed from the reactor, and the operating status of the test device and loop system in the design scheme; S7. Determine whether the fuel assembly in the core meets the technical index requirements in the simulated operation of the research reactor according to the operating status of the test device and the loop system; S8. If not satisfied, return to S6 and continue the in-pile irradiation test; S9. If the conditions are met, the fuel assembly is removed from the stack for cooling and inspection, the irradiation test of the fuel assembly is completed, and the irradiation test results are obtained.

2. The method for irradiation testing of fuel assemblies based on a high temperature and high pressure test loop as claimed in claim 1, characterized in that: The determination of the technical indicator parameters includes the following: S11. Confirm the technical index requirements of irradiation test, including power, fuel consumption, temperature, pressure and water chemical environment indicators; S12. Design the preliminary framework of core loading, test equipment and cooling circuit according to the technical index requirements; S13. Based on the preliminary framework of core loading, test equipment and cooling circuit, the feasibility and matching of technical indicator requirements are demonstrated to obtain the preliminary scheme of core loading, test equipment and cooling circuit and determine the technical indicator parameters.

3. The method for irradiation testing of fuel assemblies based on a high temperature and high pressure test loop as claimed in claim 2, characterized in that: In S13, the feasibility and compatibility demonstration of the technical indicator requirements are as follows: S131. Evaluate the neutron flux distribution and power density parameters in the core by calculation methods, and analyze the reactor thermal safety limits under different operating conditions; S132. Determine the mechanical strength and thermal performance of the test device; S133. Evaluate the flow control and pressure regulation capabilities of the cooling circuit under different operating conditions, as well as the interface compatibility with the core and the test device; S134. Based on the results of S131, S132 and S133, conduct an overall matching analysis on the preliminary framework of core loading, test device and cooling circuit, and evaluate the feasibility of the preliminary framework of core loading, test device and cooling circuit.

4. The method for irradiation testing of fuel assemblies based on a high temperature and high pressure test loop as claimed in claim 1, characterized in that: The design processes of each solution in S2 are as follows: The core loading scheme includes physical calculation methods, test core arrangement and test index parameter calculation results; The component solution to be tested includes component structure parameters and interface requirements; The test device solution includes the device structure design and the measurement point layout design; The system operation plan includes subsystem design, interface requirements and operation program design; Radiation safety and protection programmes include radiation protection management, radiation monitoring and radioactive waste management; The quality assurance program includes controls on documents, designs, items and processes.

5. The method for irradiation testing of fuel assemblies based on a high temperature and high pressure test loop as claimed in claim 1, characterized in that: The safety analysis of S3 includes physical safety analysis of core loading, safety analysis of test equipment, system safety analysis and accident safety analysis.

6. The method for irradiation testing of fuel assemblies based on a high temperature and high pressure test loop as claimed in claim 5, characterized in that: The core loading physical safety analysis adopts reactor thermal safety limit analysis, which is used to analyze whether the safety limits under different operating conditions meet the requirements.

7. The method for irradiation testing of fuel assemblies based on a high temperature and high pressure test loop as claimed in claim 5, characterized in that: The safety analysis of the test device includes device mechanical analysis and thermal analysis, which are used to analyze the structural strength and thermal-hydraulic characteristics of the test device under different working conditions.

8. The method for irradiation testing of fuel assemblies based on a high temperature and high pressure test loop as claimed in claim 5, characterized in that: The system safety analysis adopts loop pipeline safety analysis to analyze whether the loop system pipeline strength meets the requirements under different working conditions.

9. The method for irradiation testing of fuel assemblies based on a high temperature and high pressure test loop as claimed in claim 5, characterized in that: The accident safety analysis adopts a method combining probability theory and determinism to analyze the safety of systems and devices under accident conditions with multiple factors.

10. The method for irradiation testing of fuel assemblies based on a high temperature and high pressure test loop according to claim 1, characterized in that: The simulated stack irradiation test in S5 includes stack test operation and cold and hot debugging. The stack test operation is used to check whether there is structural interference between the test device and the research reactor body when the fuel assembly is loaded into the stack, and the rationality of the stack test operation; the cold and hot debugging is used to check the working status of the loop system and the test device, and record the operating data in the stack.

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