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，全世界对场址概率安全评估 (PSA) 的兴趣日益增加。然而，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。多机组事故的场外后果可能与单机组事故的场外后果不同，因此全范围现场PSA是必不可少的。在本文中，已经进行了初步的现场风险评估。建立并实施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。2级MU-PSA采用映射表法。对于第 3 级 MU-PSA，采用分组方法减少源词类别组合的数量。然后，估算了场地事故的早期死亡风险和潜在癌症风险，并分析了场地风险的趋势。通过该应用程序为具有 2 个以上不同反应堆类型单元的场址执行全范围场址 PSA 的过程有助于制定 SRA 方法、风险指标和安全目标。