Safety Assessment Of Accidents Mitigation Features Of The Advanced Pressurized Water Reactor

Advanced Pressurized Water Reactor HPR100 is G-? nuclear power plant with a significant feature of active and passive safety design philosophy and improved defense-in-depth concept is performed throughout all safety-related activities to ensure that they are subject to overlapping provisions.It provides mitigation measures and safety strategies to mitigate the consequences of Design Basis Accidents(DBA)and includes systems that help strengthen defense in depth capability and enrich Design Extension Condition(DEC)mitigation measure.The major concern of this research is to investigate the improved mitigation measurements such as passive residual heat removal system of secondary side(PRS)and the VDA cooling capability.PRS is a modern design to mitigate SBO and the failure of the turbine-driven auxiliary feedwater pumps,in order to provide feedwater to the secondary side of the SG in a passive way.This research identifies DBA management strategies devolved for current evolutionary reactors.Different scenarios(SGTR,LOFA,and SBO)have been analyzed with RELAP5/MOD3.4 computer code in order to evaluate the key system response and the important parameters history in each scenario within the reactor coolant system and the reactor core.This thesis outlines the major mitigation design features of each scenario.In SGTR event it is found that no SG overfilled,nor other thermal hydraulic limit occurred,and it is recommended that the VDA be actuated by SG level.In LOFA the ideal use of discharge condition of the VDA it can provide fast depressurization for the primary system and earlier passive system actuation.PRS can satisfy the design requirements and remove the core residual heat successfully when SBO occurs for at least 72 hours.The results are helpful to develop the management strategies and guideline for the accident of similar types of HPR1000.