Research On RISMC Safety Method Based On THEATRe

The reactor safety analysis method is an important means to evaluate the safety of nuclear power plants.The traditional reactor safety analysis methods can be divided into the Deterministic Safety Analysis method and the Probabilistic Safety Analysis method.Both of them have shortcomings.The coupling of these two methods called Risk-Informed Safety Margin Characterization analysis method developed quickly in recent years.This method studies the equipment actions and system evolutions under accident conditions.This method is more effective in exploring the uncertainty of system parameters and equipment states under accident conditions.Based on the system simulation program THEATRe,the work is to propose the realization form of the Risk-Informed Safety Margin Characterization analysis method,design and develop a safety analysis tool,and take AP1000 Station black-out accident as a case to test and analyze.After comparing the existing safety analysis methods,briefly introducing the basic concepts of the Risk-Informed Safety Margin Characterization analysis method,summarizing the current situation of safety analysis methods at home and abroad,a theoretical method which couples the Monte Carlo and the dynamic event tree method in the Risk-Informed Safety Margin Characterization analysis method with THEATRe is proposed.The input and output,the control logic and the restart function of THEATRe is changed to fit in the RISMC analysis method.Based on this,the Monte Carlo and dynamic event tree method of safety analysis tool De Mon TH overall design and module division is completed.The program is divided into a Monte Carlo module and a dynamic event tree module.Each module contains an uncertain parameter distribution module,a scene generation module,a driver module,and a data processing module.Based on the Fortran language and in accordance with the principle of modular design,the De Mon TH analysis tool is developed on the Microsoft visual studio 2017 environment.A model of AP1000 Station black-out accident is built using THEATRe.The simulation results on the model verify the correctness of the coupling method and the effectiveness of the safety analysis tool.The influence of the uncertainty of the initial water temperature of the IWRST,the power level of the reactor and the reliability of the pneumatic valve of a single series of passive safety injection system on the accident process is analyzed.The uncertainty of the initial water temperature of the IWRST will affect the startup time of the passive safe injection system.The power level of the reactor will affect the discharge of heat at the end of the accident.The reliability of pneumatic valves in a single series of passive safety injection system will affect the heat removal ability of passive residual heat removal system.