ABSTRACT

Since the Fukushima accident, interest in the site probabilistic safety assessment (PSA) has increased worldwide. However, the standard process for the site risk assessment (SRA) has not yet been established. In addition, most of these studies have focused on the level 1 and 2 PSA. The offsite consequences of the multi-unit accidents may differ from that of the single-unit accidents, so that the full-scope site PSA is essential. In this paper, the preliminary site risk assessment has been performed. The level 1 multi-unit probabilistic safety assessment (MU-PSA) methodology considering the inter-unit dependency was established and carried out. And the mapping table method was adopted in the level 2 MU-PSA. For the level 3 MU-PSA, the grouping method was adopted to reduce the number of the source-term category combinations. Then, the early fatality risk and the latent cancer risk from the accidents in a site were estimated and the tendency of the site risk was analyzed. The process of performing a full-scope site PSA for a site with more than 2 units of varied reactor types presented through this application could contribute to developing the SRA methodology, risk metrics, and safety goals.

摘要

自福岛事故以来，全球范围内对现场概率安全评估（PSA）的兴趣日益增加。但是，现场风险评估（SRA）的标准流程尚未建立。此外，这些研究大多集中在1级和2级PSA上。多单元事故的场外后果可能与单单元事故的场外后果不同，因此，全范围站点PSA是必不可少的。在本文中，已经进行了现场风险初步评估。建立并执行了考虑单元间依赖性的1级多单元概率安全评估（MU-PSA）方法。并且在2级MU-PSA中采用了映射表方法。对于3级MU-PSA，采用分组方法来减少源项分类组合的数量。然后，评估了现场事故的早期死亡风险和潜在癌症风险，并分析了现场风险的趋势。通过此应用程序为具有超过2个不同反应堆类型的单元的站点执行全范围站点PSA的过程，可能有助于开发SRA方法，风险度量和安全目标。