西安脉冲堆失水事故缓解措施分析评价

Mitigation Measures Analysis of Xi’an Pulsed Reactor During Large Break Loss of Coolant Accident

采用RELAP5系统分析程序建立了详细的西安脉冲堆系统模型,模拟了典型破口位置处大破口失水事故工况下应急补水再淹没和应急排水过程中的热工水力参数响应特性,分析了采用不同应急缓解措施的有效性和合理性,同时研究了影响应急补水再淹没瞬态过程的主要因素。结果表明:在大破口紧急停堆事故下,堆芯全失水和部分失水事故均可采取应急补水再淹没措施进行冷却,防止燃料过热;而对于大破口未紧急停堆事故,全失水和部分失水事故则应采取应急排水措施使堆芯建立空气自然循环冷却,抑制燃料温度上升。研究结论能为西安脉冲堆大破口失水事故应急缓解措施方案的制定和效果评价提供理论支撑。

A detailed system model of Xi’an pulsed reactor(XAPR)is developed by using the RELAP5 system analysis program to simulate the response characteristics of thermal hydraulic parameters during emergency reflood and emergency drainage processes under typical loss of coolant accidents(LOCA)at break locations.The effectiveness and rationality of emergency mitigation measures are analyzed,and the main factors affecting the transient process of emergency reflood are studied.The results indicate that LOCA,both with core fully and partially uncovered,can be mitigated by emergency reflood measure when the reactor emergency shutdown.The influence of main parameters on emergency reflood behavior is also analyzed.However,emergency drainage measure should be adopted to establish air natural circulation and cool the core under LOCA when the reactor emergency shutdown fails.The research results provide a theoretical support for the formulation and evaluation of emergency mitigation measures for the LOCA of XAPR.