A design method for accident diagnosis of fast reactor nuclear power plant

Abstract

The present invention provides a fast reactor nuclear power plant accident diagnosis design method, comprising: (1) based on the list of accident procedure documents, eliminating the procedure documents that are not suitable for execution guided by the accident diagnosis strategy, and forming a list of procedures to be executed guided by the accident diagnosis strategy; (2) on the basis of the list of procedures to be executed guided by the accident diagnosis strategy, sorting the accident procedures; and, based on the entry symptom information of the accident procedures, forming the entry symptom information of the accident diagnosis strategy according to the screening principle, as a criterion for judging whether to start executing the accident diagnosis strategy; (3) formulating the operation flow of the accident diagnosis strategy according to the sorted list of procedures to be executed guided by the accident diagnosis strategy and the entry symptom information of the accident diagnosis strategy. The present invention can be used to guide the design and optimization of accident diagnosis content in the accident handling guidelines and accident procedure documents of fast reactor nuclear power plants, improve the accident procedures from the perspective of strategies and measures, and effectively improve the operation safety of fast reactor nuclear power plants.

Description

Technical Field

[0001] The invention belongs to nuclear power plant design technology, and in particular relates to an accident diagnosis design method for a fast reactor nuclear power plant. Background Art

[0002] Defense in depth is a safety design requirement that is implemented throughout the safety regulations for nuclear power plant design (HAF). As the third line of defense in the principle of defense in depth, accident procedures play a vital role in limiting the development of accidents and ensuring reactor safety. Once an event or accident condition occurs, the nuclear power plant is considered to have entered an emergency state, requiring operators to use accident procedures to respond quickly, correct deviations from the operating conditions, and take necessary actions to avoid or mitigate possible consequences.

[0003] Fast reactor nuclear power plants have complex systems and many operating parameters. Considering the main process systems, safety systems, auxiliary systems and support systems required for normal operation, abnormal operation and accident conditions, the number of systems in nuclear power plants reaches thousands; the necessary information required for accident diagnosis includes but is not limited to temperature, flow, pressure, switchboard voltage, related equipment availability, radioactivity level, and comprehensive signals based on the status of process equipment. Therefore, the accident procedures involve a large number of systems, equipment, and operating parameters in nuclear power plants, and the various steps of the accident handling strategy influence and relate to each other. In order to accurately and quickly respond to accident handling needs, it is necessary to determine an accurate and efficient accident diagnosis strategy based on scientific and reasonable design method analysis.

[0004] Whether the design of the accident diagnosis strategy is reasonable is directly related to the safe operation of the power plant. Advanced accident diagnosis strategies can quickly and accurately call the accident procedure response, thereby better controlling the accident process, mitigating the consequences of the accident, and ensuring the safety of the unit. Summary of the invention

[0005] The purpose of the present invention is to provide a fast reactor nuclear power plant accident diagnosis design method based on the design characteristics and requirements of the fast reactor nuclear power plant, so as to determine an accurate and efficient accident diagnosis strategy.

[0006] The technical solution of the present invention is as follows: A fast reactor nuclear power plant accident diagnosis design method comprises the following steps:

[0007] (1) Based on the list of accident procedure documents, eliminate the procedure documents that are not applicable to the execution guided by the accident diagnosis strategy, and form a list of procedures to be executed guided by the accident diagnosis strategy;

[0008] (2) sorting the accident procedures based on the list of procedures to be executed under the guidance of the accident diagnosis strategy; and forming the accident diagnosis strategy entry symptom information according to the screening principle based on the entry symptom information of the accident procedures as a criterion for determining whether to start executing the accident diagnosis strategy;

[0009] (3) Based on the sorted list of procedures to be executed under the guidance of the accident diagnosis strategy and the entry symptom information of the accident diagnosis strategy, formulate the operation process of the accident diagnosis strategy.

[0010] Furthermore, in the above-mentioned fast reactor nuclear power plant accident diagnosis design method, in step (1), the accident procedures of eliminating the procedure files that are not applicable to the procedure files guided by the accident diagnosis strategy are as follows:

[0011] Accident procedures for handling accident conditions where the main control room is unavailable;

[0012] The accident handling work is not the accident procedure that is led by the operator in the main control room, including the accident procedure that the diagnostic signal is not based on the signal from the main control room, the accident handling operation is mainly completed on site, and the complete process of accident handling is not led by the main control room;

[0013] Accident procedures for monitoring unit status and supervising accident operations.

[0014] Further, in the above-mentioned fast reactor nuclear power plant accident diagnosis design method, in step (2), the method for sorting the accident procedures is as follows:

[0015] The accident procedures are grouped and checked in sequence according to the order of grouping and the order within the group in the accident diagnosis strategy, so as to enter the appropriate accident procedure.

[0016] The first group of accident procedures includes: accident procedures for handling accident conditions leading to radioactive release consequences, and accident procedures for handling accident conditions related to sodium leakage. The order within the group is determined according to the urgency of the relevant accident conditions;

[0017] The second group of accident procedures includes: accident procedures for handling power-related accidents, accident procedures for handling equipment cooling water accidents, and accident procedures for handling compressed air accidents. The order of the procedures within the group is in the order of power supply, equipment cooling water, and compressed air.

[0018] The third group of accident procedures are other accident procedures, and the order within the group is determined according to the urgency of the relevant accident conditions.

[0019] Furthermore, in the above-mentioned fast reactor nuclear power plant accident diagnosis design method, in step (2), the screening principle of the accident diagnosis strategy entry symptom information includes:

[0020] For each procedure, the logical combination result of the selected entry symptom information can cover all the paths entering the procedure;

[0021] For each procedure, the number of selected entry sign information is reduced; the reduction method is to define all candidate entry sign information as a candidate set, analyze the correlation between the candidate entry sign information within the candidate set, and select the subset with the best orthogonality based on the correlation analysis;

[0022] The entry indication information includes an emergency shutdown signal.

[0023] Further, in the above-mentioned fast reactor nuclear power plant accident diagnosis design method, in step (3), the operation process formulation method of the accident diagnosis strategy is as follows:

[0024] (3-1) Determine the composition of the operation process, including entry information, shutdown confirmation, inspection information, and execution information;

[0025] (3-2) Design the entry information and convert the criteria for starting to execute the accident diagnosis strategy into an executable operation process form;

[0026] (3-3) Check the emergency shutdown of the reactor and confirm the emergency shutdown operation;

[0027] (3-4) For each procedure, the accident diagnosis strategy entry symptom information is combined according to the diagnostic logic to form the inspection information corresponding to the procedure, and all logical "yes" results of the inspection information are directed to the execution of the procedure to form the execution information corresponding to the procedure. The inspection information and execution information of all procedures are combined in the order of the sorted accident procedures and spliced ​​in sequence to form a sequential operation process.

[0028] Furthermore, in the above-mentioned fast reactor nuclear power plant accident diagnosis design method, in step (3), the operation process of the accident diagnosis strategy is optimized, including:

[0029] a. For inspection information that appears multiple times in the operation process, merge the inspection points in the operation process to minimize the number of repeated inspections of the same information in the operation process;

[0030] b. For adjacent procedures, consider merging inspection information and optimizing execution processes.

[0031] The beneficial effects of the present invention are as follows:

[0032] The present invention combines the design characteristics of fast reactor nuclear power plants and the accident procedure system of fast reactor nuclear power plants for the first time, and proposes a fast reactor nuclear power plant accident diagnosis design method and strategy, which can be used to guide the design and optimization of accident diagnosis content in the accident handling guidelines and accident procedure documents of fast reactor nuclear power plants, and can improve the accident procedures in terms of strategies and measures, effectively improving the operational safety of fast reactor nuclear power plants.

[0033] The present invention proposes a hierarchical principle in the accident diagnosis strategy, provides a specific order for performing diagnostic checks on accident procedures, forms a logically reasonable, clearly ordered, accurate and efficient guidance scheme, and solves the core problem of accident diagnosis strategy design.

[0034] The present invention solves the problems faced when designing accident diagnosis strategies for fast reactor nuclear power plants, such as complex and diverse accident conditions, complex systems of fast reactor nuclear power plants, multiple operating parameters, huge numbers and types of digital signals in the main control room, and heavy operating tasks. According to the method of the present invention, an efficient human-machine interface for accident procedures can be developed to improve the efficiency of procedure execution. The designed accident diagnosis strategy can significantly reduce the workload of operators in accident diagnosis, greatly reduce the possibility of human errors in accident diagnosis, reduce misdiagnosis and misoperation, improve the treatment measures of the unit under accident conditions, and ensure the accuracy and timeliness of accident response.

[0035] The present invention has good versatility and can be combined with the design schemes of the protection system, instrumentation and control, etc. of a specific fast reactor power plant to provide an applicable accident diagnosis strategy or convert it into an accident diagnosis procedure based on the list of accident procedure documents. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The present invention is a flow chart of the fast reactor nuclear power plant accident diagnosis design method. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0038] Fast reactor nuclear power plants have complex systems and many operating parameters. Accident handling involves a large number of systems and equipment in nuclear power plants, as well as various operating parameters such as temperature, flow, pressure, and integrated signals. The various steps of the accident handling strategy influence and relate to each other. In order to accurately and quickly respond to accident handling needs, it is necessary to determine an accurate and efficient accident diagnosis strategy based on scientific and reasonable design method analysis.

[0039] The accident conditions that fast reactor accident procedures are designed to deal with are complex and diverse. In terms of the scope of accident conditions, fast reactor accident procedures are designed to deal with all design basis accidents and some beyond-design basis accidents; in terms of accident condition types, fast reactor accident procedures are designed to deal with accidents occurring in various systems such as the main container, primary, secondary, and tertiary steam turbines, electricity, compressed air, and cooling circulating water; in terms of accident signs, different accident conditions may trigger the same type of emergency shutdown signals and other accident signs, so it is necessary to distinguish the accident signs before accurately determining the accident conditions and using the corresponding accident procedures. Therefore, when dealing with accident conditions, a complete accident diagnosis strategy is needed as the general entrance to the accident procedure document system, so that accident conditions can be accurately and quickly determined based on accident signs, and the corresponding accident procedures can be called.

[0040] Under the design conditions of the digital control room, the signals used as the entry conditions of the accident procedures include alarm and non-alarm sign signals, which are extremely large in number and of various types. If the above-mentioned operation tasks are not based on a reasonable and optimized execution strategy and are directly handled by the operator, the accident diagnosis process will be time-consuming and difficult to overcome human errors. Therefore, in order to improve the handling measures of the unit under accident conditions and ensure the accuracy and timeliness of the accident response, it is necessary to design the accident diagnosis strategy according to a reasonable method.

[0041] Fast reactor nuclear power plants differ significantly from the engineering design of previous pressurized water reactor nuclear power plants in terms of system design, operation mode, accident handling, etc. Therefore, the design method of related accident diagnosis strategies developed based on pressurized water reactor nuclear power plants is difficult to solve the problems in the design process of accident diagnosis strategies for fast reactor nuclear power plants, and it is necessary to develop an accident diagnosis strategy design method suitable for fast reactor nuclear power plants.

[0042] The present invention specifically describes the fast reactor nuclear power plant accident diagnosis design method from aspects such as regulation scope, troubleshooting sequence, entry mode, and operation flow.

[0043] 1) Scope of the Regulation

[0044] Based on List 1: "Accident Procedure Document List", according to the following principles, eliminate the procedure documents that are not applicable to the execution guided by the accident diagnosis strategy, so as to determine the scope of procedures to be executed under the guidance of the accident diagnosis strategy.

[0045] Principle 11: Accident procedures for handling the accident condition of main control room unavailability

[0046] For example, accident procedures for evacuating main control room personnel due to fire, high radioactivity, etc.

[0047] Principle 12: Accident handling is not an accident procedure led by the operator in the main control room.

[0048] Specifically, ① the diagnostic signal is not based on the signal from the main control room, and ② the accident handling operations are mainly completed on site, and ③ the complete process of accident handling is not an accident procedure led by the main control room.

[0049] For example, accident procedures for handling fuel handling accident conditions.

[0050] Principle 13: Accident procedures for monitoring unit status and supervising accident operations

[0051] For example, the incident diagnosis procedure itself.

[0052] Form List 2: "List of procedures guided by the accident diagnosis strategy".

[0053] 2) Check order

[0054] Based on List 2, the accident procedures are sorted according to the following two-level principles. After the accident occurs, the accident diagnosis strategy is checked in this order to enter the appropriate accident procedure.

[0055] Table 1 ranks the accident procedures according to the following two levels of principles

[0056]

[0057] Form List 3: "Ranked list of procedures guided by the incident diagnosis strategy".

[0058] 3) Entry method

[0059] There are many types of entry symptom information in the accident procedures of fast reactor nuclear power plants, such as the temperature or pressure information of various fluids such as coolant desalted water in the power plant, the operating status information or fault signals of various key equipment such as main pumps, the radioactivity level information in various areas of the power plant, and the voltage or power supply fault signals of key equipment in the power plant. Based on List 2, this method selects the entry symptom information that meets the following principles 31-33 based on the entry symptom information of the accident procedures.

[0060] Principle 31: Scramble Signal

[0061] Principle 32: Completeness

[0062] For each procedure, the logical combination result of the selected entry symptom information can cover all the paths entering the procedure.

[0063] Principle 33: Keep it simple

[0064] For each procedure, the number of selected entry sign information is reduced. The reduction method is to define all candidate entry sign information as a candidate set; within the candidate set, analyze the correlation between the candidate entry sign information (i.e., analyze the degree of information overlap between the candidate entry sign information); based on the correlation analysis, select the subset with the best orthogonality (i.e., select the subset with the highest degree of information mutual exclusion between the entry sign information).

[0065] This information together with the emergency shutdown signal forms List 4: "Accident diagnosis strategy entry symptom information".

[0066] The criterion for starting to execute the accident diagnosis strategy is: each signal in List 4 can be regarded as a variable with two states of "yes" and "no"; the criterion is defined as the result of the OR logic operation of each signal in List 4. That is, when any signal in List 4 appears, the accident diagnosis strategy is started.

[0067] 4) Operation process

[0068] According to List 3, List 4 and "Criteria", formulate the operation process of accident diagnosis strategy. After the accident occurs, the operator shall follow the operation process, implement the accident diagnosis strategy, check the relevant information and enter the corresponding accident procedures.

[0069] The operating procedures are formulated as follows:

[0070] A. Operation process composition

[0071] The content of the operation process consists of "entry information", "confirmation of shutdown", "inspection information" and "execution information".

[0072] B. Entry Information

[0073] The criteria for starting to implement the accident diagnosis strategy are converted into an executable operational process; the downstream link of the input information is to confirm the shutdown of the reactor.

[0074] C. Confirm shutdown

[0075] It includes checking the emergency shutdown of the reactor and confirming the operations of the emergency shutdown; the downstream links of confirming the shutdown are inspection information and execution information.

[0076] D. Check information, execute information

[0077] For a procedure, take out the relevant entry symptom information in List 4 and combine them according to reasonable diagnostic logic to form the inspection information corresponding to this procedure;

[0078] All logical "yes" results of the check information point to the execution of the procedure, forming the execution information corresponding to the procedure;

[0079] According to the order of List 3, combine the inspection information and execution information of all procedures and splice them in sequence to form a sequential operation process.

[0080] The operation process formulated in the above order generally contains redundant process links, which can be optimized according to the following methods:

[0081] a. For inspection information that appears multiple times in the operation process, consider optimizing the operation process by merging checkpoints, etc., to minimize the number of repeated inspections of the same information in the operation process;

[0082] b. For adjacent procedures, consider merging inspection information and optimizing execution processes.

[0083] Example

[0084] The above technical solution is described in detail below:

[0085] (1) Scope of the Regulation

[0086] Based on List 1, according to Principles 11, 12, and 13, the following procedural documents are not applicable to guidance:

[0087] Table 2 Procedure scope screening

[0088]

[0089] List 2 is formed as follows:

[0090] Table 3 List 2

[0091] Procedure Items Regulation 1 Regulation 4 …… Regulation i …… Procedure

[0092] (2) Checking order

[0093] Create a checklist of procedures as follows.

[0094] Table 4 ranks the accident procedures according to the following two levels of principles

[0095]

[0096] Form List 3: "Ranked list of procedures guided by the incident diagnosis strategy".

[0097] Table 5 List 3

[0098] Procedure Items Execution Order Regulation 8 1 Regulation 11 2 Regulation 1 3 Regulation 4 4 Regulation 5 5 Regulation 6 6 Regulation 9 7 Regulation 10 8 Regulation 7 9 Regulation 14 10 Regulation 13 11 Regulation 12 12 Regulation 15 13

[0099] (3) Entry method

[0100] Based on List 2, filter the accident procedure entry symptom information.

[0101] Table 6 Screening of accident procedure entry sign information

[0102]

[0103] Provide a list of emergency shutdown signals:

[0104] Table 7 Emergency shutdown signal list

[0105] Emergency shutdown signal content Emergency shutdown signal 1 The reactor emergency shutdown was triggered by …… …… Emergency shutdown signal …… …… …… Emergency shutdown signal ……

[0106] Table 6 and Table 7 are combined to obtain List 4.

[0107] Table 8 List 4 - Accident Diagnosis Strategy Entry Symptom Information

[0108] Entrance sign information source Sign 1: … Regulation 1 Sign 2: … Regulation 1 …… …… Signs i... Emergency shutdown signal …… …… Signs: ... Regulation 15

[0109] The result of the OR logic operation of each signal in List 4 is used as the criterion for determining whether to start executing the accident diagnosis strategy.

[0110] (4) Operation process

[0111] The "entry information", "shutdown confirmation", "inspection information" and "execution information" are spliced ​​together according to the formulation method of the operating process, and optimized according to the optimization method to form the accident diagnosis strategy operating process.

[0112] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0113] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A fast reactor nuclear power plant accident diagnosis design method, characterized in that: The steps include: (1) Based on the list of accident procedure documents, eliminate the procedure documents that are not applicable to the execution guided by the accident diagnosis strategy, and form a list of procedures to be executed guided by the accident diagnosis strategy; (2) sorting the accident procedures based on the list of procedures to be executed under the guidance of the accident diagnosis strategy; and forming the accident diagnosis strategy entry symptom information according to the screening principle based on the entry symptom information of the accident procedures as a criterion for determining whether to start executing the accident diagnosis strategy; The method for sequencing incident procedures is as follows: The accident procedures are grouped and checked in sequence according to the order of grouping and the order within the group in the accident diagnosis strategy, so as to enter the appropriate accident procedure. The first group of accident procedures includes: accident procedures for handling accident conditions leading to radioactive release consequences, and accident procedures for handling accident conditions related to sodium leakage. The order within the group is determined according to the urgency of the relevant accident conditions; The second group of accident procedures includes: accident procedures for handling power-related accidents, accident procedures for handling equipment cooling water accidents, and accident procedures for handling compressed air accidents. The order of the procedures within the group is in the order of power supply, equipment cooling water, and compressed air. The third group of accident procedures are other accident procedures, and the order within the group is determined according to the urgency of the relevant accident conditions; The screening principles of the accident diagnosis strategy entry symptom information include: For each procedure, the logical combination result of the selected entry symptom information can cover all the paths entering the procedure; For each procedure, reduce the amount of entry symptom information selected; The entry sign information includes an emergency shutdown signal; (3) Based on the sorted list of procedures to be executed under the guidance of the accident diagnosis strategy and the entry symptom information of the accident diagnosis strategy, formulate the operation process of the accident diagnosis strategy.

2. The fast reactor nuclear power plant accident diagnosis design method according to claim 1, characterized in that: In step (1), the accident procedures that are not applicable to the procedure files executed under the guidance of the accident diagnosis strategy are eliminated as follows: Accident procedures for handling accident conditions where the main control room is unavailable; The accident handling work is not the accident procedure that is led by the operator in the main control room, including the accident procedure that the diagnostic signal is not based on the signal from the main control room, the accident handling operation is mainly completed on site, and the complete process of accident handling is not led by the main control room; Accident procedures for monitoring unit status and supervising accident operations.

3. The fast reactor nuclear power plant accident diagnosis design method according to claim 1, characterized in that: The method for simplifying the selected entry sign information is as follows: defining all candidate entry sign information as a candidate set, analyzing the correlation between the candidate entry sign information within the candidate set, and selecting the subset with the best orthogonality as the entry sign information of each procedure based on the correlation analysis.

4. The fast reactor nuclear power plant accident diagnosis design method according to claim 1, characterized in that: In step (2), when any signal in the accident diagnosis strategy entry sign information appears, the accident diagnosis strategy begins to be executed.

5. The fast reactor nuclear power plant accident diagnosis design method according to claim 1, characterized in that: In step (3), the operation process of the accident diagnosis strategy is formulated as follows: (3-1) Determine the composition of the operation process, including entry information, shutdown confirmation, inspection information, and execution information; (3-2) Design the entry information and convert the criteria for starting to execute the accident diagnosis strategy into an executable operation process form; (3-3) Check the emergency shutdown of the reactor and confirm the emergency shutdown operation; (3-4) For each procedure, the accident diagnosis strategy entry symptom information is combined according to the diagnostic logic to form the inspection information corresponding to the procedure, and all logical "yes" results of the inspection information are directed to the execution of the procedure to form the execution information corresponding to the procedure. The inspection information and execution information of all procedures are combined in the order of the sorted accident procedures and spliced ​​in sequence to form a sequential operation process.

6. The fast reactor nuclear power plant accident diagnosis design method according to claim 5, characterized in that: In step (3), the operation process of the accident diagnosis strategy is optimized, including: a. For inspection information that appears multiple times in the operation process, merge the inspection points in the operation process to minimize the number of repeated inspections of the same information in the operation process; b. For adjacent procedures, consider merging inspection information and optimizing execution processes.

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