多堆厂址始发事件分析探讨

Analysis and Discussion on Initial Event of Multi-unit

多堆厂址一级概率安全评价(PSA)研究中,机组数目的增加使得建模工作量剧增,给整个核电厂的风险评估带来困难。结合已有基础,本文研究了多堆厂址始发事件分析的筛选方法,提出利用堆芯损伤频率(CDF)上下限值评估方法,分析厂址内不同机组数对厂址CDF的影响。结果表明,双机组厂址适合优先进行具体分析。针对双机组核电站,对多堆厂址内各始发事件进行筛选。结果表明,丧失厂外电、丧失热阱等事件适合建模分析,并对其他筛选结果给出后续分析建议,为多堆厂址一级PSA后续事故序列建模工作提供了重要基础。

In the multi-unit level 1 probabilistic safety assessment(PSA)study,the modeling workload greatly increases due to the increase of the number of units,which brings difficulties to the risk assessment of the whole nuclear power plants.Based on the existing foundation,the method for preliminary evaluation of initiating event consequences in a site was studied in this paper.The calculation method of core damage frequency(CDF)upper and lower bounds was used to analyze the influence of the number of units on CDF in the site.The results show that the two-unit site is suitable for priority analysis.In view of the dual-unit site,the initial events within the multi-unit site were screened.The results show that the loss-of-offsite-power(LOOP),loss of heat trap and other events are suitable for modeling and analysis.Recommendations were also made for other screening results.This paper provides an important basis for the modeling of the level 1 PSA subsequent accident sequence at multi-unit sites.