Cost-Benefit-Risk Analysis Spreadsheets for Probabilistic Safety Assessment Applications

As background to the technical approach and analytical tools described in this paper, it is appropriate to present an overview of current issues and developments in the commercial nuclear power industry that provide strong motivation for application of probabilistic safety assessment (PSA) to trade-off studies involving costs, benefits, safety, and associated risks at nuclear facilities. There have been several ongoing and recent developments within the U.S. Nuclear Regulatory Commission (NRC) related to the formulation and application of policy on the use of PSA and risk-based regulation in general. Since the landmark development and review of the original “Reactor Safety Study” (WASH-1400) in the late 1970s, the issue of PSA applications has been a topic of great interest and controversy in the commercial nuclear power industry and at the NRC. The issue of PSA applications to reactor plant regulation has gained momentum, particularly since the issuance and implementation of NRC Generic Letter 88–20 and its supplements that mandated the Individual Plant Examinations (IPE) and subsequent Individual Plant Examinations for External Events (IPEEE). Virtually all of the commercial nuclear power plants in the United States chose to perform a plant-specific PSA to address these requirements. In an effort to improve the state of the art of plant-specific PSAs, the NRC sponsored a study that resulted in a second landmark report on PSA called, “Severe Accident Risks: An Assessment of Five U.S. Nuclear Power Plants,” (NUREG-1150) in 1991. Several key reports, most notably NUREG/CR-4550 and NUREG/CR-4551, have been issued as supporting documentation for NUREG-1150.