2019

Tyrväinen, Tero; Björkman, Kim

In site probabilistic safety assessment (PSA), a nuclear power plant site is analysed as a whole considering all reactor units and other facilities with radionuclide sources. Site PSA especially focuses on dependencies between different units and locations of the radionuclide sources. Most PSAs are unit specific and there are no well-established methods for site PSA. Besides general method development, procedures are needed for documenting the site PSA, managing possible modifications made to the single-unit PSA models, and managing the data and computation. This report provides guidance for site PSA model management and discusses the needs for a site PSA database. This report is closely connected to a site PSA method described in a separate report and it considers the same analysis phases. The report discusses single-unit PSA models from site PSA perspective, site PSA documentation and the database for site PSA. Guidelines for site PSA documentation and model management tasks in different analysis phases and in the maintenance phase are given. The focus of the report is on level 1 issues, but also level 2 aspects are covered.