Reliability Modeling And Analysis Of Conventional Island Instrument System

The nuclear power plant instrument control system is responsible for data collection and processing,control and regulation,diagnosis,communication and other functions during the operation of the unit.It is the nerve center of the nuclear power plant.When a design basis accident or an over design basis accident occurs,it still needs to be normal and reliable operation,so the reliability of the instrumentation system is critical to nuclear power plants.The thesis conducts reliability analysis on the conventional island instrument system of nuclear power.The main research work of this paper is as follows:By abstracting and simplifying the composition of the conventional island instrument system,the events and instrument components that affect the reliability of the nuclear island conventional island instrument system are sorted out.Then the dynamic fault tree model is introduced to model the instrument system.In the process of analyzing the dynamic fault tree model of the instrument system and the dynamic fault tree model with the exponential distribution of the bottom events,a modified Markov-Monte Carlo method was proposed to modularize the fault tree and simplify the simulation calculation of the model complexity;DSPN-Monte Carlo method is used for the simulation calculation of the dynamic fault tree of the instrument system where the bottom event does not obey the exponential distribution or the combination of the bottom event is more complicated and there are factors such as "common cause failure".In the experimental part,the typical systems involved in the nuclear island conventional island instrument system,the condensate system and the water supply system,and the instrument power supply system are selected for dynamic fault tree modeling and the reliability-related indicators are calculated,and then recommendations are made on system reliability in design and maintenance.The simulation results of the nuclear power conventional island instrument system reliability dynamic fault tree analysis method and the trapezoidal formula method proposed by the research are similar,but the calculation time is shortened by half and the efficiency is higher.