Seismic Response and Fragility Analysis of Residual Heat Removal Piping System for Nuclear Power Plant

Abstract

The residual heat removal (RHR) is one of the systems of the emergency core cooling system (ECCS) When the loss of coolant accident (LOCA) happens the high pressure water injection system cannot maintain the water level in reactor and will activate low pressure water injection system - residual heat removal system (RHR) in order to supply the cooling water for reactor to maintain the water level The purpose is to remove the residual heat generated by the reactor core and avoid the hazard induced due to high core temperature According to the final safety analysis report of the sample nuclear power plant (NPP) in the accident sequence that has the greatest contribution to inducing reactor core meltdown the ac-independent water addition system (ACIWA) is the main cause In addition in the ACIWA system risk achievement worth (RAW) of rupture of the RHR piping is the highest among all components in NPP Therefore this dissertation takes the RHR piping in the ACIWA system of the sample NPP as the research object Firstly the finite element software ABAQUS is used to analyze the flange joints in the RHR piping which are more complicated in analysis procedure and may cause liquid leakage in the piping Then the results of 4-point bending test are used to verify the correctness of the flange joint model This joint is further used in the RHR piping system shaking table model and the correctness of the model is verified by shaking table test The ultimate goal of this dissertation is to establish the fragility curve of the RHR system and discuss the variables supposed to be considered and how to select them in the fragility analysis method proposed by Reed and Kennedy Combined with the numerical model analysis results the fragility curve is finally drawn which serves as the reference for seismic probabilistic risk assessment (SPRA) The analysis results show that the RHR piping system in the sample NPP has good seismic performance and the probability of damage caused by earthquakes is very low which is not a key equipment affecting the safety of sample NPP

Date of Award	2019
Original language	English
Supervisor	Hsuan-Teh Hu (Supervisor)