Method for computing maloperation rate of nuclear power station system

Abstract

The invention provides a method for computing the maloperation rate of a nuclear power station system. Based on the MooN architecture of the Markov principle, namely when M components among N components of the nuclear power station are under a normal working condition, the nuclear power station system is capable of working normally, and the state space diagram of the nuclear power station related system and a nuclear power station system failure frequency steady-state expression as shown in the description are established, wherein lambda refers to the maloperation failure rate and mu refers to the repair rate. When a processing and maintenance policy changes, no computational model needs to be re-established and only related parameters are modified to obtain the result after the adjustment of the maintenance policy.

Description

technical field [0001] The invention belongs to the technical field of safety-level instrumentation and control in the field of nuclear power, and in particular relates to a calculation method for a system malfunction rate of a nuclear power plant. Background technique [0002] Malfunction rate refers to the frequency of safety-level I&C systems mis-executing safety functions due to their own random failures (that is, the failure of components of the safety-level I&C system itself causes system misoperations) under normal on-site working conditions. Once the safety-level I&C system executes the safety function, the on-site working conditions are forcibly terminated. At this time, a series of investigation, recording, recovery and other processing measures need to be carried out until the cause of the safety function execution is found out and the on-site working conditions are restored to a continuable level. Only in the running state can the on-site working conditions be re...

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Problems solved by technology

However, this standard does not provide a general calculation method for the misoperation rate. Therefore, at present, mainstream nuclear power I&C suppliers have independently derived calculation methods for the system misoperation rate based on reliability theory and combined with their own practical experience. For example, Mitsubishi Corporation uses the reliability block diagram theory to calculate the misoperation rate, and Westinghouse and AREVA use the fault tree theory to derive the calculation formula of the misoperation rate

[0004] Since the overall structure of the safety-level instrumentation and control system is generally a MooN-type voting system (ie: M voting system out of N, such as 4 out of 2, 3 out of 2, 2 out of 1, etc., this type of system consists of N independent and identically distributed components The system can work normally only if M or more than M components work normally), which belongs to the repairable system, and the maintenance strategy is relatively complicated. Both the block diagram and the fault tree theory have deficiencies:

The input event of the logic gate is the "cause" of the output event, and the output event of the logic gate is the "effect" of the input event. It can be seen that although the model can intuitively reflect the maintenance strategy, a model can only reflect one maintenance strategy. When it is necessary to compare different maintenance strategies, it is necessary to re-establish several different models for evaluation and comparison, which will generate a huge workload for systems with a large number of units and complex structures

[0010] The reason for this is that although the model can intuitively reflect the maintenance strategy, a model can only reflect one maintenance strategy. When it is necessary to compare different maintenance strategies, it is necessary to re-establish several different fault tree models for evaluation Compare

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