Method and device for determining reliability requirement of instrument control system of nuclear power plant

Abstract

The invention discloses a method and a device for determining reliability requirements of an instrument control system of a nuclear power plant. The method comprises the following steps: identifying DEC-A working conditions and analyzing functional requirements of the instrument control system for coping with the DEC-A working conditions; performing top layer design on the instrument control system coping with the DEC-A working condition based on the functional requirements, and determining a top layer design scheme; carrying out detailed design on the instrument control system coping with the DEC-A working condition based on the top-layer design scheme, and determining an instrument control equipment list coping with the DEC-A working condition; and providing a reliability requirement for the instrument control equipment in the instrument control equipment list. Based on the method for determining the reliability requirement of the instrument control system coping with the DEC-A working condition, the economical efficiency and safety of a nuclear power plant can be guaranteed, and support can be provided for design of a new reactor type instrument control system.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear power plant design, and particularly relates to a method and device for determining the reliability requirements of an instrument control system of a nuclear power plant. Background Art

[0002] With the introduction of digital instrument control technology and the proposal of the concept of design extension conditions in the "Design Safety Rules for Nuclear Power Plants" (HAF102-2016), the standard configuration of newly built nuclear power units is an instrument control system for coping with DBA (usually the reactor protection system) and an instrument control system for coping with DEC-A conditions (usually the diverse drive system). A diverse drive system is designed to cope with the design extension conditions in the event of the failure of the reactor protection system. The reactor protection system has clear index requirements in the nuclear safety guide "Design of Instrument and Control Systems for Nuclear Power Plants" (HAD102 / 10-2021), that is, a general limit value of 1E-04 to 1E-05 failures / demands is adopted in probabilistic safety analysis. However, for the design of the instrument control system for coping with DEC-A conditions, there are currently the following problems: the reliability requirements of the instrument control system for coping with DEC-A conditions itself and the corresponding design implementation; the reliability requirements and the corresponding design implementation under the combined design of the instrument control system for coping with DEC-A conditions and the instrument control system for coping with DBA. There is no strict design logic for the independence problem in the current design implementation, only the processing unit is independent, and there is a lack of reliability requirements and determination methods for the equipment of the instrument control system for coping with DEC-A conditions. If the reliability requirements of the instrument control system for coping with DEC-A conditions are too high, it will affect the economy of the power plant; if the reliability requirements are too low, it will affect the safety of the power plant.

[0003] The existing patent CN118886780A discloses a method for determining the performance indicators of nuclear power plant maintenance rules. This method classifies and combines the functions of the target system according to the risk importance level and operating state, divides the parts required to implement each function into equipment lists at the equipment level, intermediate level, and plant level, where the intermediate level includes one of the column level or system level, and uses the equipment columns obtained by dividing the equipment in the equipment list at the equipment level and the equipment list at the intermediate level as the index calculation items, calculates the reliability indicators and unavailability indicators of each index calculation item respectively, and uses the reliability indicators and unavailability indicators of the index calculation items as the performance indicators of the nuclear power plant maintenance rules.

[0004] The existing patent CN103854133A discloses a method and system for evaluating the performance indicators of a nuclear power plant mitigation system. First, the plant functional systems to be monitored and the equipment of the plant functional systems are determined, and the relevant source data for calculating the mitigation system performance indicator (MSPI) of the plant functional systems is obtained. Then, the mitigation system performance indicator (MSPI) of the plant functional systems is calculated based on the relevant source data. Finally, the risk level of the plant functional systems is judged according to the mitigation system performance indicator (MSPI) and the set usage criteria for the mitigation system performance indicator.

[0005] In summary, neither of the above two existing patents solves the problems of uncertain plant economy and safety risks faced in the prior art due to the lack of a method for determining the reliability requirements of the I&C system for coping with the DEC-A condition. Summary of the Invention

[0006] Based on the above technical problems, the present invention proposes a method and device for determining the reliability requirements of the I&C system of a nuclear power plant, which solves the problems of uncertain plant economy and safety risks faced in the prior art due to the lack of a method for determining the reliability requirements of the I&C system for coping with the DEC-A condition.

[0007] To achieve the above object, the present invention proposes a method for determining the reliability requirements of the I&C system of a nuclear power plant.

[0008] A method for determining the reliability requirements of the I&C system of a nuclear power plant, the method comprising:

[0009] Identifying the DEC-A condition and analyzing the functional requirements of the I&C system for coping with the DEC-A condition;

[0010] Based on the functional requirements, performing a top-level design on the I&C system for coping with the DEC-A condition and determining the top-level design scheme;

[0011] Based on the top-level design scheme, performing a detailed design on the I&C system for coping with the DEC-A condition and determining the list of I&C equipment for coping with the DEC-A condition;

[0012] Proposing reliability requirements for the I&C equipment in the list of I&C equipment.

[0013] Further, identifying the DEC-A condition includes:

[0014] Obtaining the initiating event frequency and the failure probability of the I&C system for coping with the DBA condition;

[0015] Based on the initiating event frequency and the failure probability of the I&C system for coping with the DBA condition, identifying the DEC-A condition.

[0016] Furthermore, analyze the functional requirements of the I&C system for coping with the DEC-A condition, including:

[0017] Analyze the mitigation functions required by the I&C system for coping with the DEC-A condition;

[0018] Determine the system for implementing the mitigation functions and propose the start signal requirements for the system.

[0019] Furthermore, based on the functional requirements, perform a top-level design of the I&C system for coping with the DEC-A condition, including:

[0020] Design the I&C system for coping with the DEC-A condition and the I&C system for coping with the DBA in a non-fully independent manner to form a first top-level design scheme;

[0021] Design the I&C system for coping with the DEC-A condition and the I&C system for coping with the DBA in a completely independent manner to form a second top-level design scheme.

[0022] Furthermore, the first top-level design scheme includes:

[0023] Use the same sensors for the I&C system for coping with the DEC-A condition and the I&C system for coping with the DBA, and the input channels and output channels of the personnel operation instructions are the same.

[0024] Furthermore, the second top-level design scheme includes:

[0025] Use different sensors for the I&C system for coping with the DEC-A condition and the I&C system for coping with the DBA, and the input channels and output channels of the personnel operation instructions are independent of each other.

[0026] Furthermore, determine the top-level design scheme, including:

[0027] Determine the first failure probability of the I&C system for coping with the DEC-A condition under the first top-level design scheme;

[0028] Determine the second failure probability of the I&C system for coping with the DEC-A condition under the second top-level design scheme;

[0029] Based on the first failure probability and the second failure probability, determine the top-level design scheme in combination with engineering factors.

[0030] Furthermore, based on the top-level design scheme, perform a detailed design of the I&C system and determine the list of I&C equipment for coping with the DEC-A condition, including:

[0031] According to the initiating event frequency and the failure probability of the I&C system for coping with the DBA, determine the preliminary reliability requirements and independence requirements of the I&C system;

[0032] Based on the preliminary reliability requirements and the independence requirements of the I&C system, establish a PSA model for the I&C system to cope with DEC-A;

[0033] Use the PSA model to determine the corresponding core damage frequency;

[0034] Judge whether the core damage frequency meets the preset probabilistic safety goal;

[0035] If the core damage frequency meets the preset probabilistic safety goal, generate a list of I&C equipment for coping with DEC-A conditions.

[0036] Furthermore, put forward reliability requirements for the I&C equipment in the list of I&C equipment, including:

[0037] Put forward preliminary reliability requirements for the I&C equipment in the list of I&C equipment;

[0038] Based on the preliminary reliability requirements, use the PSA model to conduct a sensitivity analysis of the I&C equipment;

[0039] According to the results of the sensitivity analysis, update the preliminary reliability requirements for the I&C equipment.

[0040] Furthermore, put forward preliminary reliability requirements for the I&C equipment in the list of I&C equipment, including:

[0041] Take the reliability parameter values of the I&C equipment in the list of I&C equipment in the PSA model as the preliminary reliability requirements of the I&C equipment, and the reliability parameter values include the probability of failure.

[0042] Furthermore, according to the results of the sensitivity analysis, update the preliminary reliability requirements for the I&C equipment, including:

[0043] Adopt different sensitivity parameter factors and calculate the core damage frequency under the sensitivity parameter factors;

[0044] Compare the core damage frequency under the sensitivity parameter factors with the preset probabilistic safety goal;

[0045] Update the preliminary reliability requirements for the I&C equipment according to the comparison results.

[0046] Furthermore, it also includes:

[0047] Judge whether the I&C equipment planned to cope with DEC-A conditions meets the reliability requirements of the I&C equipment;

[0048] If the I&C equipment for coping with the DEC-A condition in the plan does not meet the reliability requirements, the reliability data corresponding to the I&C equipment is input into the PSA model to determine the corresponding core damage frequency.

[0049] Judge whether the core damage frequency meets the preset probabilistic safety goal.

[0050] If the core damage frequency meets the preset probabilistic safety goal, it is determined that the I&C equipment for coping with the DEC-A condition in the plan is available.

[0051] A device for determining the reliability requirements of an I&C system in a nuclear power plant, comprising:

[0052] An identification and analysis module, configured to identify the DEC-A condition and analyze the functional requirements of the I&C system for coping with the DEC-A condition.

[0053] A top-level design module, which performs top-level design on the I&C system for coping with the DEC-A condition based on the functional requirements and determines the top-level design scheme.

[0054] A detailed design module, which performs detailed design on the I&C system for coping with the DEC-A condition based on the top-level design scheme and determines the list of I&C equipment for coping with the DEC-A condition.

[0055] A determination module, configured to put forward reliability requirements for the I&C equipment in the list of I&C equipment.

[0056] Further, the identification and analysis module is configured to:

[0057] Obtain the initiating event frequency and the failure probability of the I&C system for coping with the DBA condition.

[0058] Based on the initiating event frequency and the failure probability of the I&C system for coping with the DBA condition, identify the DEC-A condition.

[0059] Further, the identification and analysis module is configured to:

[0060] Analyze the mitigation functions required by the I&C system for coping with the DEC-A condition.

[0061] Determine the system for performing the mitigation function and put forward the startup signal requirements for the system.

[0062] Further, the top-level design module is configured to:

[0063] Design the I&C system for coping with the DEC-A condition and the I&C system for coping with the DBA non-fully independently to form a first top-level design scheme.

[0064] Completely independently design the I&C system for coping with the DEC-A condition and the I&C system for coping with the DBA to form a second top-level design solution.

[0065] Further, the first top-level design solution includes:

[0066] Use the same sensors for the I&C system for coping with the DEC-A and the I&C system for coping with the DBA, and the input and output channels of the personnel operation instructions are the same.

[0067] Further, the second top-level design solution includes:

[0068] Use different sensors for the I&C system for coping with the DEC-A and the I&C system for coping with the DBA, and the input and output channels of the personnel operation instructions are independent of each other.

[0069] Further, determining the top-level design solution includes:

[0070] Determine the first failure probability of the I&C system for coping with the DEC-A condition under the first top-level design solution;

[0071] Determine the second failure probability of the I&C system for coping with the DEC-A condition under the second top-level design solution;

[0072] Based on the first failure probability and the second failure probability, determine the top-level design solution in combination with engineering factors.

[0073] Further, the detailed design module is used for:

[0074] According to the initiating event frequency and the failure probability of the I&C system for coping with the DBA, determine the preliminary reliability requirements and independence requirements for the I&C system for coping with the DEC-A;

[0075] According to the preliminary reliability requirements and the independence requirements of the I&C system, establish a PSA model for the I&C system for coping with the DEC-A;

[0076] Use the PSA model to determine the corresponding core damage frequency;

[0077] Judge whether the core damage frequency meets the preset probabilistic safety goal;

[0078] If the core damage frequency meets the preset probabilistic safety goal, generate a list of I&C equipment for coping with the DEC-A condition.

[0079] Further, the determination module is used for:

[0080] Put forward preliminary reliability requirements for the I&C equipment in the list of I&C equipment.

[0081] Based on the preliminary reliability requirements, perform a sensitivity analysis on the I&C equipment using the PSA model;

[0082] Update the preliminary reliability requirements for the I&C equipment according to the results of the sensitivity analysis.

[0083] Furthermore, put forward preliminary reliability requirements for the I&C equipment in the I&C equipment list, including:

[0084] Take the reliability parameter values of the I&C equipment in the PSA model in the I&C equipment list as the preliminary reliability requirements for the I&C equipment, and the reliability parameter values include the failure probability.

[0085] Furthermore, update the preliminary reliability requirements for the I&C equipment according to the results of the sensitivity analysis, including:

[0086] Adopt different sensitivity parameter factors and calculate the core damage frequency under the sensitivity parameter factors;

[0087] Compare the core damage frequency under the sensitivity parameter factors with the preset probabilistic safety goal;

[0088] Update the preliminary reliability requirements for the I&C equipment according to the comparison results.

[0089] Furthermore, it also includes:

[0090] Judge whether the I&C equipment planned to cope with the DEC-A condition meets the reliability requirements of the I&C equipment;

[0091] If the I&C equipment planned to cope with the DEC-A condition does not meet the reliability requirements, input the corresponding reliability data of the I&C equipment into the PSA model to determine the corresponding core damage frequency;

[0092] Judge whether the core damage frequency meets the preset probabilistic safety goal;

[0093] If the core damage frequency meets the preset probabilistic safety goal, determine that the I&C equipment planned to cope with the DEC-A condition is available.

[0094] Based on the above technical solutions, the present invention has at least the following beneficial effects:

[0095] 1. The present invention conducts a top-level design on the I&C system for coping with the DEC-A condition by comprehensively considering the safety and economy of nuclear power plants, and combines the preliminary reliability requirements of I&C equipment for coping with the DEC-A condition to form a method for determining the reliability requirements of I&C equipment for coping with the DEC-A condition. This method can fill the gap in the design and reliability requirement determination method of the I&C system for coping with the DEC-A condition in nuclear power plants guided by risks, and can provide support for the design of the I&C system of new reactor types.

[0096] 2. When the reliability data of the I&C equipment planned to cope with the DEC-A condition do not meet the determined reliability requirements of the I&C equipment, the present invention inputs the reliability data of the I&C equipment planned to cope with the DEC-A condition into the PSA model to determine the corresponding core damage frequency, so as to verify the reliability of the I&C equipment planned to cope with the DEC-A condition. BRIEF DESCRIPTION OF THE DRAWINGS

[0097] The accompanying drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0098] Figure 1 is a flowchart of a method for determining the reliability requirements of an I&C system of a nuclear power plant according to an embodiment of the present invention;

[0099] Figure 2 is a flowchart of a method for determining the reliability requirements of an I&C system of a nuclear power plant according to another embodiment of the present invention;

[0100] Figure 3 is a schematic diagram of a device for determining the reliability requirements of an I&C system of a nuclear power plant according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0101] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0102] The following further describes the present invention in detail with specific embodiments, and these embodiments should not be construed as limiting the scope claimed by the present invention.

[0103] Embodiment

[0104] In order to solve the problems of uncertain plant economy and safety risks faced in the prior art due to the lack of a method for determining the reliability requirements of the I&C system for coping with the DEC-A condition, the present invention proposes a method and device for determining the reliability requirements of the I&C system of a nuclear power plant.

[0105] To achieve the above object, the present invention proposes a method for determining the reliability requirements of the I&C system of a nuclear power plant.

[0106] As Figure 1 shown in the flowchart of the method for determining the reliability requirements of the I&C system of a nuclear power plant according to an embodiment of the present invention, as Figure 1 shown, the method includes the following steps:

[0107] S1. Identify the DEC-A condition and analyze the functional requirements of the I&C system for coping with the DEC-A condition.

[0108] Before this step, first identify the design extension DEC-A condition that does not cause obvious damage to the reactor core through engineering judgment, determinism, and probability theory. Subsequently, conduct an analysis of the mitigation measures for coping with the DEC-A condition, identify the functional requirements of the I&C system that need to be additionally added in the design only for coping with the DEC-A condition, and finally complete the functional requirement analysis of the I&C system for coping with the DEC-A condition.

[0109] Furthermore, identifying the DEC-A condition includes: obtaining the initiating event frequency and the failure probability of the I&C system for coping with the DBA condition; based on the initiating event frequency and the failure probability of the I&C system for coping with the DBA condition, identify the DEC-A condition.

[0110] The analysis of the functional requirements of the I&C system for coping with the DEC-A condition includes the following process:

[0111] S101. Analyze the mitigation functions required by the I&C system for coping with the DEC-A condition.

[0112] As shown in Table 1, examples of the DEC-A condition and the functional analysis of the I&C system for coping with the DEC-A condition are given.

[0113] Table 1 Functional Requirement Analysis of the I&C System for Coping with the DEC-A Condition

[0114]

[0115]

[0116] S102. Determine the system for implementing the mitigation function and propose the start signal requirements of the system.

[0117] Taking the typical I&C system of a nuclear power plant for coping with the DEC-A condition triggering an emergency shutdown through DAS as an example, as shown in Table 2, the functional requirement analysis of the I&C system for coping with the DEC-A condition is shown.

[0118] Table 2 Functional Requirement Analysis of the I&C System for Coping with the DEC-A Condition

[0119]

[0120] S2. Correspondingly, conduct a top-level design for the I&C system under the DEC-A condition based on the functional requirements, and determine the top-level design scheme.

[0121] The purpose of this step is to propose an I&C system design scheme from the perspective of forward design based on the mitigation system requirements analysis for the DEC-A condition in step S1, while considering the accident mitigation function and the impact of accidental startup during normal operation on unplanned outages. In addition, iterate with professionals such as I&C design and layout, procurement, and technical economy to balance the safety and economy of the nuclear power plant.

[0122] Conduct a top-level design for the I&C system under the DEC-A condition, including the following two design schemes: non-fully independently design the I&C system under the DEC-A condition and the reactor protection system to form the first top-level design scheme; fully independently design the I&C system under the DEC-A condition and the reactor protection system to form the second top-level design scheme.

[0123] Specifically, for the first top-level design scheme, the I&C system under the DEC-A condition and the reactor protection system use the same sensor, and the input and output channels of the personnel operation instructions are the same. For this first top-level design scheme, when the I&C systems for coping with DBA and the DEC-A condition use the same sensor design, the failure of the sensor will cause both the RRP system and the DAS system to be unavailable. However, since the RRP system is a mitigation system for coping with DBA accidents and its sensors are designed with 4 channels, the failure of the sensor will only occur when all 3 channels of sensors fail. The sensor design of this RRP system has a high redundancy, so this design scheme is still acceptable.

[0124] Furthermore, for the second top-level design scheme, it includes: the I&C system under the DEC-A condition and the reactor protection system use different sensors, and the input and output channels of the personnel operation instructions are independent of each other. Taking the DAS system as an example, the DAS I&C system and the RRP system are completely independent, and they use different sensor designs, and the input and output channels related to the personnel operation instructions are independent of each other. This design scheme can avoid the common cause failure of the RRP and DAS systems and is safer than the first top-level design scheme. However, this scheme will make the I&C system design and layout complex, may involve the procurement of different sensor manufacturers, as well as the tests and maintenance during the operation of the power plant, which may affect the economy of the power plant.

[0125] Furthermore, determine the top-level design scheme, including:

[0126] S201. Determine the first failure probability of the I&C system under the DEC-A condition under the first top-level design scheme.

[0127] S202. Determine the second failure probability of the I&C system for coping with the DEC-A condition under the second top-level design scheme.

[0128] S203. Determine the top-level design scheme based on the first failure probability, the second failure probability, and in combination with engineering factors.

[0129] For a certain signal function, assume that the failure probability of the RRP system for coping with the DBA condition is Q 1A , where the failure probability of the sensor is Q 1a , the failure probability of other hardware of the automatic signal is Q 1aa , and the probability of human error (including the relevant hardware for the operator's operation) is Q 1aaa ; the failure probability of the DAS system for coping with the DEC-A condition is Q 2A , where the failure probability of the sensor is Q 2a , the failure probability of other hardware of the automatic signal is Q 2aa , and the probability of human error (including the relevant hardware for the operator's operation) is Q 2aaa . The following will calculate the failure probability of the I&C system under the first top-level design scheme and the second top-level design scheme based on the above data.

[0130] First top-level design scheme: The I&C systems for coping with the DBA and DEC-A conditions adopt the design of the same sensor, and the input channels and output channels of the human operation instructions are the same, that is, Q 1a and Q 2a are the same failure event, Q 1aaa and Q 2aaa are the same failure event. Then, under a certain function, the failure probability Q M of the I&C system = Q 1A* Q 2A = ((Q 1a+ Q 1aa ) * Q 1aaa ) * ((Q 2a+ Q 2aa ) * Q 2aaa ) = Q 1a * Q 1aaa + Q 1aa * Q 1aaa * Q 2aa。

[0131] Second top-level design scheme: The sensors of the I&C systems for coping with the DBA and DEC-A conditions adopt a completely independent design. Then, under a certain function, the failure probability Q N of the I&C system = Q 1A* Q 2A = ((Q 1a + Q 1aa ) * Q1aaa )*((Q 2a+ Q 2aa )*Q 2aaa ) = Q 1aa *Q 1aaa *Q 2a *Q 2aaa *H + Q 1a *Q 1aaa *Q 2aa *Q 2aaa *H + Q 1aa *Q 1aaa *Q 2aa *Q 2aaa *H + Q 1a *Q 1aaa *Q 2a *Q 2aaa *H, where H is the correlation factor with Q 1aaa with Q 2aaa correlation factor of

[0132] Taking the high neutron fluence rate high reactor trip at the high setpoint of the power range as an example, the implementation and comparison process of the above top - level design scheme are further described. Under the first top - level design scheme, both the RRP and DAS systems are designed to trip when the neutron fluence rate at the high setpoint of the power range is high for 2 / 4 channels, and the manual operations to trigger the RRP and DAS systems are the same human - factor event. Under the first top - level design scheme, the RRP system is designed with 4 channels and trips when the neutron fluence rate at the high setpoint of the power range is high for 2 / 4 channels; the DAS system is designed to trip with a single independent sensor, and the manual operations to trigger the RRP and DAS systems are two human - factor events. Based on the above step S203, it can be determined that the probability of both the RRP and DAS systems corresponding to the first top - level design scheme failing is 2E - 06, and the probability of both the RRP and DAS systems corresponding to the second top - level design scheme failing is 3E - 09. This calculation shows that under the second top - level design scheme, the failure probability of the I&C system is much lower than that of the first top - level design scheme with a non - independent DAS system. However, compared with the non - fully independent DAS system, the fully independent DAS system will bring new requirements for the plant layout, procurement, and operation and maintenance. It is necessary to combine the plant design safety objectives, economic indicators, on - site layout conditions, etc., and through the evaluation of safety and economy, determine the final top - level design scheme of the I&C system. For example, if the use of a fully independent DAS system greatly increases the difficulty of layout, procurement, and operation and maintenance, posing a challenge to the economy, and the safety is demonstrated to meet the requirements, a non - fully independent DAS system can be selected.

[0133] S3. Based on the top - level design scheme, conduct a detailed design of the I&C system for coping with the DEC - A condition, and determine the list of I&C equipment for coping with the DEC - A condition.

[0134] Based on the top-level design of the instrumentation and control system for DEC-A condition proposed in step 2, the detailed design of the instrumentation and control system for DEC-A condition is carried out and the PSA model is constructed. Through the demonstration with the probabilistic safety goal and the iteration of design optimization, the detailed design of the instrumentation and control system for DEC-A condition is determined, and the list of instrumentation and control equipment for DEC-A condition is determined.

[0135] Furthermore, the instrumentation and control system is designed in detail based on the top-level design plan, and the instrumentation and control equipment list for DEC-A working condition is determined, including:

[0136] S301: Determine the preliminary reliability and independence requirements of the I&C system based on the frequency of initiating events and the failure probability of the I&C system in response to DBA.

[0137] At present, the design of DAS system trigger signal is based on engineering experience. This patent uses the risk guidance method to analyze the demand of DAS system trigger signal and the preliminary reliability and independence requirements of DAS system for the condition where the frequency value of the DEC-A sequence of the initiating event superimposed on the RRP system failure exceeds 1E-08, and provides support for the detailed design of DAS system. The channels of the reactor protection system are generally physically isolated, and the rooms where the channels are located are generally not arranged adjacently, and there is a certain height under the cabinet. Therefore, the impact of fire and flooding is not considered. The preliminary reliability and independence requirements analysis table of the DAS system is shown in Table 3.

[0138] Based on the failure frequency of the initiating event superimposed on the RRP system, determine whether it is necessary to set up the DAS system (i.e., the preliminary reliability requirements of the DAS system), specifically: if the failure frequency of the initiating event superimposed on the RRP system is higher than the DEC-A sequence screening value, the DAS system needs to be set up; if the failure frequency of the initiating event superimposed on the RRP system is lower than the DEC-A sequence screening value, the DAS system does not need to be set up.

[0139] In the case where a DAS system is required, the failure frequency of the initiating event and the RRP system is determined based on whether the DAS needs to be designed independently. For example, if the failure frequency of the initiating event and the RRP system is high, greater than 1E-4, the DAS needs to be designed independently; if the failure frequency of the initiating event and the RRP system is low, less than 1E-6, the DAS does not need to be designed independently; in other cases, the satisfaction of the probabilistic safety goals in the subsequent steps determines whether the DAS needs to be designed independently.

[0140] Since earthquakes have a high degree of uncertainty, the layout of the DAS system should try to consider the independence requirements from the reactor protection system layout.

[0141] Table 3 Analysis of preliminary reliability requirements and independence requirements of DAS system

[0142]

[0143]

[0144] S302. Based on the preliminary reliability requirements and independence requirements of the I&C system, establish a PSA model for the I&C system to cope with DEC-A.

[0145] For example, for the DEC-A sequence of the transient accident superimposed on the failure of the RRP system to shut down the reactor, since its frequency is relatively high, about 8E-05 / reactor-year, it is necessary to set up an I&C system to cope with the DEC-A condition, that is, the DAS system. By modeling the failures of sensors, signal isolation and distribution, data acquisition, calculation, threshold comparison, signal logic, etc., establish a reliability model of the DAS system, and add the reliability model of the DAS system to the original PSA model that only considers the RRP system.

[0146] S303. Use the PSA model to determine the corresponding core damage frequency.

[0147] The total core damage frequency can be approximately expressed as the sum of the CDFs of all initiating events: The CDF of each initiating event is the combination of all system function failures that may lead to the failure of the mitigation of this initiating event, and is approximately expressed as: CDF IE(i) = F IE(i) ×∑[Q SYSA(i) + Q SYSB(i) + Q SYSC(i) ×Q SYSD(i) ……], where CDF IE(i) represents the CDF caused by a certain initiating event; F IE(i) represents the occurrence frequency of this initiating event; Q SYSA(i) , Q SYSB(i) , Q SYSC(i) , Q SYSD(i) represent the reliability of the functions required by each system to mitigate this initiating event.

[0148] S304. Judge whether the core damage frequency meets the preset probabilistic safety goal.

[0149] Since the sequence of transient superposition on the failure of the RRP system in the example only appears in the power and low shutdown conditions, taking the core damage frequency (CDF) target value of 1E-06 / reactor-year as an example, considering the contribution of the shutdown condition and the disaster, the CDF caused by the internal events in the power and low shutdown conditions is recommended to be lower than 1.5E-07 / reactor-year. That is, in this embodiment, when the core damage frequency is lower than 1.5E-07 / reactor-year, it meets the preset probabilistic safety goal.

[0150] S305, if the core damage frequency meets the preset probabilistic safety goal, generate a list of I&C equipment for coping with the DEC-A condition.

[0151] Specifically, when the core damage frequency meets the preset probabilistic safety goal, determine the systems, equipment, monitoring, and measuring instruments, etc. used to cope with the DEC-A condition accident according to the design scheme of the I&C system under different accidents, and obtain the list of equipment and instruments required to cope with the DEC-A accident. For example: Under a certain accident, the I&C system equipment for coping with the DEC-A condition includes steam generator feedwater flow sensors (TFM049 / 050 / 051MD), auxiliary feedwater flow sensors (TFA011 / 031 / 012 / 032 / 013 / 033MD), etc. If the core damage frequency does not meet the probabilistic safety goal, propose the design optimization direction based on risk insights and further optimize the design scheme.

[0152] S4, propose reliability requirements for the I&C equipment in the list of I&C equipment.

[0153] Furthermore, propose reliability requirements for the I&C equipment in the list of I&C equipment, including:

[0154] S401, propose preliminary reliability requirements for the I&C equipment in the list of I&C equipment.

[0155] Specifically, take the reliability parameter values (such as failure rate / failure probability) of the I&C equipment in the PSA model as the preliminary reliability requirements of the I&C equipment, and the reliability parameter values include failure probability. Table 4 shows examples of reliability requirements for typical I&C equipment.

[0156] Table 4 Examples of reliability requirements for typical I&C equipment

[0157]

[0158]

[0159] S402, based on the preliminary reliability requirements, perform a sensitivity analysis on the I&C equipment using the PSA model.

[0160] Increase or decrease the failure probability / frequency of each equipment group by a certain ratio F. The ratio F is called the sensitivity factor. During the sensitivity analysis process, use PSA modeling software to adjust the sensitivity factor F, increase or decrease the reliability parameters of typical I&C equipment by F times, realize the change of reliability parameters, and calculate the impact of different reliability parameters on the CDF. An example of sensitivity analysis of typical I&C equipment is shown in Table 5, where, f CDF-0 is the occurrence frequency of the current baseline CDF; f CDF-U is the occurrence frequency of the CDF when the failure probability of the relevant equipment group increases to F times; fCDF－L The occurrence frequency of CDF when the failure probability of the relevant equipment group is reduced to 1 / F; the sensitivity S is the ratio of f CDF-U and f CDF-L .

[0161] Table 5 Example of sensitivity analysis of typical I&C equipment for DEC-A accident mitigation

[0162]

[0163] S403. According to the results of the sensitivity analysis, update the preliminary reliability requirements for the I&C equipment.

[0164] Furthermore, according to the results of the sensitivity analysis, update the preliminary reliability requirements for the I&C equipment, including:

[0165] S4031. Use different sensitivity parameter factors to calculate the core damage frequency under the sensitivity parameter factors.

[0166] Use different sensitivity factors such as 10, 20, 30, 40, 50, etc. to calculate the influence degree of different equipment failure probabilities on the core damage frequency CDF.

[0167] S4032. Compare the core damage frequency under the sensitivity parameter factors with the preset probabilistic safety goal.

[0168] S4033. Update the preliminary reliability requirements for the I&C equipment according to the comparison results.

[0169] For example: If the corresponding CDF still meets the probabilistic safety goal after reducing the reliability of the I&C equipment by 10 times, the reliability requirements for the I&C equipment provided by the manufacturer can be reduced, and this process is to update the preliminary reliability requirements for the I&C equipment.

[0170] Furthermore, in another embodiment of the present invention, after putting forward reliability requirements for the I&C equipment in the I&C equipment list, further determine whether the I&C equipment provided by the supplier for coping with the DEC-A condition meets the reliability requirements and is available. As Figure 2 shown, this process includes the following steps:

[0171] S5. Judge whether the I&C equipment planned to cope with the DEC-A condition meets the reliability requirements of the I&C equipment.

[0172] The I&C equipment planned to cope with the DEC-A condition is the I&C equipment provided by the supplier for coping with the DEC-A condition. According to the reliability analysis or operation experience report of the I&C equipment provided by the supplier, judge whether the I&C equipment meets the reliability requirements of the DEC-A equipment under the probabilistic safety goal determined in the above step S4.

[0173] S6. If the I&C equipment planned for coping with the DEC-A condition does not meet the reliability requirements, input the corresponding reliability data of the I&C equipment into the PSA model to determine the corresponding core damage frequency.

[0174] To quantitatively evaluate the reliability of the I&C equipment provided by the supplier, according to the determined failure mode or fault mode of the corresponding equipment, it is recommended that the I&C equipment information provided by the supplier be as follows to support the calculation of the reliability parameters of the I&C equipment provided by the manufacturer:

[0175] 1) Failure rate or mean time between failures (MTBF), including the analysis and demonstration process; 2) Failure probability, that is, the ratio of the number of times of failing to change the state as expected to the number of times of needing to change the state within the specified time, including the analysis and demonstration process; 3) Failure detection factor, the proportion of failures that can be detected by means such as online diagnosis, including the analysis and demonstration process; 4) Mean time to repair (MTTR), including the analysis and demonstration process.

[0176] S7. Judge whether the core damage frequency meets the preset probabilistic safety goal.

[0177] S8. If the core damage frequency meets the preset probabilistic safety goal, it is determined that the I&C equipment planned for coping with the DEC-A condition is available.

[0178] If the preset probabilistic safety goal is met, the reliability of the equipment meets the requirements. If the safety goal is not met, identify the weak links of the I&C equipment, put forward the reliability requirements for the corresponding equipment, communicate with the manufacturer to improve the reliability of the equipment, or carry out design optimization work until the probabilistic safety goal requirements are met.

[0179] To achieve the same purpose as the above method, the present invention also proposes a device for determining the reliability requirements of an I&C system in a nuclear power plant.

[0180] As Figure 3 A schematic diagram of a device for determining the reliability requirements of an I&C system in a nuclear power plant is shown. The device includes an identification and analysis module 41, a top-level design module 42, a detailed design module 43 and a determination module 44.

[0181] The identification and analysis module 41 is used to identify the DEC-A condition and analyze the functional requirements of the I&C system for coping with the DEC-A condition.

[0182] Further, the identification and analysis module 41 is used for:

[0183] Obtain the initiating event frequency and the failure probability of the I&C system for coping with the DBA condition;

[0184] Identify the DEC-A condition based on the frequency of the originating event and the failure probability of the I&C system for coping with the DBA condition.

[0185] Furthermore, the identification and analysis module 41 is used for:

[0186] Analyze the mitigation functions required for the I&C system for coping with the DEC-A condition;

[0187] Determine the system for implementing the mitigation function and propose the startup signal requirements for the system.

[0188] The top-level design module 42 performs a top-level design on the I&C system for coping with the DEC-A condition based on the functional requirements and determines the top-level design solution;

[0189] Furthermore, the top-level design module 42 is used for:

[0190] Design the I&C system for coping with the DEC-A condition and the I&C system for coping with the DBA non-fully independently to form the first top-level design solution;

[0191] Design the I&C system for coping with the DEC-A condition and the I&C system for coping with the DBA completely independently to form the second top-level design solution.

[0192] Furthermore, the first top-level design solution includes:

[0193] Use the same sensor for the I&C system for coping with the DEC-A and the I&C system for coping with the DBA, and the input channels and output channels of the personnel operation instructions are the same.

[0194] Furthermore, the second top-level design solution includes:

[0195] Use different sensors for the I&C system for coping with the DEC-A and the I&C system for coping with the DBA, and the input channels and output channels of the personnel operation instructions are independent of each other.

[0196] Furthermore, determining the top-level design solution includes:

[0197] Determine the first failure probability of the I&C system for coping with the DEC-A condition under the first top-level design solution;

[0198] Determine the second failure probability of the I&C system for coping with the DEC-A condition under the second top-level design solution;

[0199] Based on the first failure probability and the second failure probability, determine the top-level design solution in combination with engineering factors.

[0200] The detailed design module 43 conducts a detailed design of the I&C system for coping with the DEC-A condition based on the top-level design scheme, and determines the I&C equipment list for coping with the DEC-A condition;

[0201] Furthermore, the detailed design module 43 is used for:

[0202] Determine the preliminary reliability requirements and independence requirements of the I&C system for coping with DEC-A according to the initiating event frequency and the failure probability of the I&C system for coping with DBA;

[0203] Establish a PSA model of the I&C system for coping with DEC-A according to the preliminary reliability requirements and independence requirements of the I&C system;

[0204] Use the PSA model to determine the corresponding core damage frequency;

[0205] Judge whether the core damage frequency meets the preset probabilistic safety goal;

[0206] If the core damage frequency meets the preset probabilistic safety goal, generate an I&C equipment list for coping with the DEC-A condition.

[0207] The determination module 44 is used to put forward reliability requirements for the I&C equipment in the I&C equipment list.

[0208] Furthermore, the determination module 44 is used for:

[0209] Put forward preliminary reliability requirements for the I&C equipment in the I&C equipment list;

[0210] Based on the preliminary reliability requirements, conduct a sensitivity analysis of the I&C equipment using the PSA model;

[0211] Update the preliminary reliability requirements of the I&C equipment according to the results of the sensitivity analysis.

[0212] Furthermore, putting forward preliminary reliability requirements for the I&C equipment in the I&C equipment list includes:

[0213] Take the reliability parameter values of the I&C equipment in the I&C equipment list in the PSA model as the preliminary reliability requirements of the I&C equipment, and the reliability parameter values include failure probability.

[0214] Furthermore, updating the preliminary reliability requirements of the I&C equipment according to the results of the sensitivity analysis includes:

[0215] Adopt different sensitivity parameter factors to calculate the core damage frequency under the sensitivity parameter factors;

[0216] Compare the core damage frequency under the sensitivity parameter factor with the preset probabilistic safety goal;

[0217] Update the preliminary reliability requirements for the I&C equipment according to the comparison result.

[0218] Furthermore, it also includes:

[0219] Judge whether the I&C equipment planned to cope with the DEC-A condition meets the reliability requirements of the I&C equipment;

[0220] If the I&C equipment planned to cope with the DEC-A condition does not meet the reliability requirements, input the reliability data corresponding to the I&C equipment into the PSA model to determine the corresponding core damage frequency;

[0221] Judge whether the core damage frequency meets the preset probabilistic safety goal;

[0222] If the core damage frequency meets the preset probabilistic safety goal, determine that the I&C equipment planned to cope with the DEC-A condition is available.

[0223] It should be understood that the description of the device for determining the reliability requirements of a nuclear power plant I&C system is consistent with the corresponding method embodiment for determining the reliability requirements of a nuclear power plant I&C system, so this embodiment will not be elaborated here.

[0224] In summary, as can be seen from the above description, the above embodiments of the present invention achieve the following technical effects:

[0225] 1. The present invention comprehensively considers the safety and economy of a nuclear power plant to conduct a top-level design of the I&C system for coping with the DEC-A condition, and combines the preliminary reliability requirements of the I&C equipment for coping with the DEC-A condition to form a method for determining the reliability requirements of the I&C equipment for coping with the design extension condition of the un-melted reactor. This method can fill the gap in the method for designing the I&C system for coping with the DEC-A condition and determining the reliability requirements in a risk-guided nuclear power plant, and can provide support for the design of the I&C system of a new reactor type.

[0226] 2. When the reliability data of the I&C equipment planned to cope with the DEC-A condition do not meet the determined reliability requirements of the I&C equipment, the present invention inputs the reliability data of the I&C equipment planned to cope with the DEC-A condition into the PSA model to determine the corresponding core damage frequency, so as to verify the reliability of the I&C equipment planned to cope with the DEC-A condition.

[0227] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

[0228] It should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the existence of additional identical elements in the process, method, article or device comprising the element.

[0229] The logic and / or steps represented in the flowchart or described otherwise herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, which can be specifically implemented in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, a system including a processor, or other systems that can fetch instructions from the instruction execution system, apparatus, or device and execute the instructions.

[0230] It should be understood that each part of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, any one or a combination of the following techniques well known in the art can be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), etc.

[0231] It should be noted that in the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

Claims

1. A method for determining the reliability requirements of an instrument control system in a nuclear power plant, characterized in that, Including: Identifying the DEC-A condition and analyzing the functional requirements of the I&C system for coping with the DEC-A condition; Based on the functional requirements, conducting a top-level design for the I&C system for coping with the DEC-A condition and determining the top-level design scheme; Based on the top-level design scheme, conducting a detailed design for the I&C system for coping with the DEC-A condition and determining the list of I&C equipment for coping with the DEC-A condition; Putting forward reliability requirements for the I&C equipment in the list of I&C equipment.

2. The method according to claim 1, wherein Identifying the DEC-A condition, including: Obtaining the initiating event frequency and the failure probability of the I&C system for coping with the DBA condition; Based on the initiating event frequency and the failure probability of the I&C system for coping with the DBA condition, identifying the DEC-A condition.

3. The method according to claim 1, characterized in that, Analyzing the functional requirements of the I&C system for coping with the DEC-A condition, including: Analyzing the mitigation functions required by the I&C system for coping with the DEC-A condition; Determining the system for implementing the mitigation functions and putting forward the start signal requirements for the system.

4. The method according to any one of claims 1 to 3, characterized in that Based on the functional requirements, conducting a top-level design for the I&C system for coping with the DEC-A condition, including: Non-fully independently designing the I&C system for coping with the DEC-A condition and the I&C system for coping with the DBA condition to form a first top-level design scheme; Fully independently designing the I&C system for coping with the DEC-A condition and the I&C system for coping with the DBA condition to form a second top-level design scheme.

5. The method according to claim 4, wherein The first top-level design scheme includes: Using the same sensors for the I&C system for coping with the DEC-A condition and the I&C system for coping with the DBA condition, and the input channels and output channels of the personnel operation instructions are the same.

6. The method according to claim 4, characterized in that The second top-level design scheme includes: Using different sensors for the I&C system for coping with the DEC-A condition and the I&C system for coping with the DBA condition, and the input channels and output channels of the personnel operation instructions are independent of each other.

7. The method according to claim 4, characterized in that, Determining the top-level design scheme, including: Determining the first failure probability of the I&C system for coping with the DEC-A condition under the first top-level design scheme; Determining the second failure probability of the I&C system for coping with the DEC-A condition under the second top-level design scheme; Based on the first failure probability and the second failure probability, determining the top-level design scheme in combination with engineering factors.

8. The method according to claim 2, wherein Based on the top-level design scheme, conducting a detailed design for the I&C system and determining the list of I&C equipment for coping with the DEC-A condition, including: According to the initiating event frequency and the failure probability of the I&C system for coping with the DBA condition, determining the preliminary reliability requirements and independence requirements of the I&C system; According to the preliminary reliability requirements and the independence requirements of the I&C system, establishing a PSA model for the I&C system for coping with the DEC-A condition; Using the PSA model to determine the corresponding core damage frequency; Judging whether the core damage frequency meets the preset probabilistic safety goal; If the core damage frequency meets the preset probabilistic safety goal, generating a list of I&C equipment for coping with the DEC-A condition.

9. The method according to claim 8, characterized in that, Putting forward reliability requirements for the I&C equipment in the list of I&C equipment, including: Put forward preliminary reliability requirements for the I&C equipment in the I&C equipment list; Based on the preliminary reliability requirements, use the PSA model to conduct a sensitivity analysis on the I&C equipment; Update the preliminary reliability requirements for the I&C equipment according to the results of the sensitivity analysis.

10. The method according to claim 9, characterized in that, Put forward preliminary reliability requirements for the I&C equipment in the I&C equipment list, including: Take the reliability parameter values of the I&C equipment in the I&C equipment list in the PSA model as the preliminary reliability requirements for the I&C equipment, and the reliability parameter values include the failure probability.

11. The method according to claim 9, wherein Update the preliminary reliability requirements for the I&C equipment according to the results of the sensitivity analysis, including: Adopt different sensitivity parameter factors and calculate the core damage frequency under the sensitivity parameter factors; Compare the core damage frequency under the sensitivity parameter factors with the preset probabilistic safety goal; Update the preliminary reliability requirements for the I&C equipment according to the comparison results.

12. The method according to claim 11, characterized in that, It also includes: Judge whether the I&C equipment planned to cope with the DEC-A condition meets the reliability requirements of the I&C equipment; If the I&C equipment planned to cope with the DEC-A condition does not meet the reliability requirements, input the corresponding reliability data of the I&C equipment into the PSA model to determine the corresponding core damage frequency; Judge whether the core damage frequency meets the preset probabilistic safety goal; If the core damage frequency meets the preset probabilistic safety goal, determine that the I&C equipment planned to cope with the DEC-A condition is available.

13. A device for determining the reliability requirements of an instrument control system in a nuclear power plant, characterized in that, It includes: An identification and analysis module, used to identify the DEC-A condition and analyze the functional requirements of the I&C system for coping with the DEC-A condition; A top-level design module, used to conduct a top-level design on the I&C system for coping with the DEC-A condition based on the functional requirements and determine the top-level design scheme; A detailed design module, used to conduct a detailed design on the I&C system for coping with the DEC-A condition based on the top-level design scheme and determine the I&C equipment list for coping with the DEC-A condition; A determination module, used to put forward reliability requirements for the I&C equipment in the I&C equipment list.

14. The device according to claim 13, wherein The identification and analysis module is used for: Obtain the initiating event frequency and the failure probability of the I&C system for coping with the DBA condition; Based on the initiating event frequency and the failure probability of the I&C system for coping with the DBA condition, identify the DEC-A condition.

15. The device according to claim 13, characterized in that, The identification and analysis module is also used for: Analyze the mitigation functions required by the I&C system for coping with the DEC-A condition; Determine the system for implementing the mitigation function and put forward the start signal requirements for the system.

16. The device according to any one of claims 13 to 15, characterized in that, The top-level design module is used for: Design the I&C system for coping with the DEC-A condition and the I&C system for coping with the DBA non-fully independently to form a first top-level design scheme; Fully independently design the I&C system for coping with the DEC-A condition and the I&C system for coping with the DBA to form a second top-level design scheme.

17. The device according to claim 16, wherein The first top-level design scheme includes: The same sensor is used for the I&C system for coping with DEC-A and the I&C system for coping with DBA, and the input channels and output channels of the personnel operation instructions are the same.

18. The device according to claim 16, characterized in that, The second top-level design scheme includes: Different sensors are used for the I&C system for coping with DEC-A and the I&C system for coping with DBA, and the input channels and output channels of the personnel operation instructions are independent of each other.

19. The device according to claim 16, characterized in that, Determining the top-level design scheme includes: Determining the first failure probability of the I&C system for coping with the DEC-A condition under the first top-level design scheme; Determining the second failure probability of the I&C system for coping with the DEC-A condition under the second top-level design scheme; Based on the first failure probability and the second failure probability, combining engineering factors to determine the top-level design scheme.

20. The device according to claim 14, characterized in that The detailed design module is used for: According to the initiating event frequency and the failure probability of the I&C system for coping with DBA, determining the preliminary reliability requirements and independence requirements of the I&C system for coping with DEC-A; According to the preliminary reliability requirements and the independence requirements of the I&C system, establishing a PSA model for the I&C system for coping with DEC-A; Using the PSA model to determine the corresponding core damage frequency; Judging whether the core damage frequency meets the preset probabilistic safety goal; If the core damage frequency meets the preset probabilistic safety goal, generating a list of I&C equipment for coping with the DEC-A condition.

21. The device according to claim 20, characterized in that, The determining module is used for: Putting forward preliminary reliability requirements for the I&C equipment in the I&C equipment list; Based on the preliminary reliability requirements, performing a sensitivity analysis on the I&C equipment using the PSA model; According to the results of the sensitivity analysis, updating the preliminary reliability requirements of the I&C equipment.

22. The device according to claim 21, characterized in that, Putting forward preliminary reliability requirements for the I&C equipment in the I&C equipment list includes: Taking the reliability parameter values of the I&C equipment in the I&C equipment list in the PSA model as the preliminary reliability requirements of the I&C equipment, and the reliability parameter values include the failure probability.

23. The device according to claim 21, wherein According to the results of the sensitivity analysis, updating the preliminary reliability requirements of the I&C equipment includes: Using different sensitivity parameter factors to calculate the core damage frequency under the sensitivity parameter factors; Comparing the core damage frequency under the sensitivity parameter factors with the preset probabilistic safety goal; Updating the preliminary reliability requirements of the I&C equipment according to the comparison results.

24. The device according to claim 23, characterized in that, It also includes: Judging whether the I&C equipment planned to cope with the DEC-A condition meets the reliability requirements of the I&C equipment; If the I&C equipment planned to cope with the DEC-A condition does not meet the reliability requirements, inputting the corresponding reliability data of the I&C equipment into the PSA model to determine the corresponding core damage frequency; Judging whether the core damage frequency meets the preset probabilistic safety goal; If the core damage frequency meets the preset probabilistic safety goal, determining that the I&C equipment planned to cope with the DEC-A condition is available.

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