State-of-the-Art Reactor Consequence Analyses Project: Uncertainty Analyses for Station Blackout Scenarios

This paper provides an overview of the U.S. Nuclear Regulatory Commission’s (NRC’s) project to develop a technical report summarizing the most important insights from its three State-of-the-Art Reactor Consequence Analyses (SOARCA) project uncertainty analyses (UAs). The NRC, with Sandia National Laboratories, has completed three UAs as part of the SOARCA project, for three different operating reactor types in three different locations in the United States. The SOARCA UAs included an integrated evaluation of uncertainty in accident progression, radiological release, and off-site health consequence projections. These three UAs are currently documented in three detailed reports. The NRC is currently developing a technical overview report summarizing the important insights from the three SOARCA UAs. The purpose of the NRC summary is to provide a useful reference for regulatory applications that require the evaluation of off-site consequence risk from beyond-design-basis-event severe accidents. Examples include regulatory and cost-benefit analyses that rely on off-site consequence projections using the MELCOR Accident Consequence Code System (MACCS) code, in conjunction with MELCOR for source term characterization. This paper provides an overview and discusses the overall scope and methodology of the SOARCA UAs and the approach for the summary report currently under development.