核电厂地震概率安全评价中的电气设备易损度计算

The Fragility Computation of Electric Equipment in Nuclear Power Plant's Seismic Probabilistic Safety Assessment

随着福岛事故的发生,核电厂外部事件概率安全评价工作的重要性被各国核安全当局所认同。而地震,作为核电厂最为主要的外部事件,其对应的概率安全评价工作便更为人们所重视。易损度计算是完成地震概率安全评价的关键技术环节,其结果将被使用作概率安全评价事故序列模型的输入条件。因此,易损度计算的准确性和正确性对地震概率安全评价工作最终结论的影响也就不言而喻了。本文首先总体性介绍了设备易损度计算的基础数学模型,随后详细描述了核电厂地震概率安全评价中电气设备易损度计算的操作步骤,并重点探讨了电气设备功能失效模式下对试验反应谱和要求反应谱的处理简化技巧,最后通过具体算例阐述了电气设备易损度计算过程中的注意事项和简化技巧应用。

With the occurrence of Fukushima nuclear accident, the necessity of external events probabilistic safety assessment （PSA） for nuclear power plants is gradually recognized by nuclear safety administrations in various countries. Moreover, earthquake, as the original responsible cause of Fukushima nuclear accident, is identified as one of the most important external events which deserve special attention from the PSA＇s perspective. The fragility computation, the calculated results of which would be used as input subjects for PSA accident sequence model, is one indispensable step to accomplish the seismic probabilistic safety assessment （SPSA）. Based on this fact, the accuracy and validity of fragility calculation contribute a significant impact to the final conclusion of SPSA. In this paper, the fundamental mathematic theory ofequipment fragility computation is briefly introduced at first, and then the general procedure of fragility calculation for electrical equipment is given with test response spectrum and required response spectrum clipping techniques in functional failure mode specially discussed in the following sections. In the last part of this paper, one explicit fragility computation example of electrical switchgear is offered, with the purpose of revealing some matters needing special attention and useful finesses to facilitate the calculation during the computation.