堆芯下支承板失效模式及影响因素研究

Study on Failure Modes and Influenced Factors of Lower Support Plate

堆芯下支承板作为反应堆堆内构件,用于承载整个堆芯的质量,核电厂严重事故下支承板的失效过程对于事故进程的发展和缓解措施的有效性都有着重要影响。针对堆芯下支承板结构特点,结合严重事故下堆芯熔化进程,研究确定了机械失效、机械熔融混合失效和熔融失效3种堆芯下支承板的失效模式,以及温度、熔融材料、水环境和熔融物作用位置等4方面影响失效模式的重要因素;并针对各因素开展了分析,从而为严重事故下堆芯熔融物的行为与现象研究和核安全审评提供基础。

The lower support plate was used as the reactor internal component to carry the weight of the whole core.The failure process of the lower support plate under the serious accident of the nuclear power plant played an important role in the development of the accident process and the effectiveness of mitigation measures.According to the structural characteristics of the lower support plate,combined with the melting process of the core under serious accidents,three failure modes of the lower support plate were studied and determined,including mechanical failure,mechanical melting mixed failure and melting failure,and four important factors affecting the failure mode,such as temperature,melting material,water environment and melting position,were studied and analyzed,so as to provide the basis for the behavior and phenomenon research and nuclear safety assessment of core melt under serious accident.