Seismic margin assessment of mitigation systems in Oskarshamn

This paper describes a pilot study to estimate the seismic margin of mitigation systems in Oskarshamn Unit 1 nuclear power plant in Sweden. The mitigation concept developed by OKG/AB consists of the filter vented containment and an independent containment spray system. These systems are being designed to meet the seismic standards currently used in Sweden. Some of the components of these systems interface with the existing systems in Oskarshamn Unit 1 which are not designed to today's exacting seismic criteria. OKG/AB wants to ensure that the interfacing systems and components adequately support the successful performance of the mitigation concept in the event of a severe accident caused by an earthquake. A seismic margin assessment was proposed as a cost-effect approach to achieve this goal