Molten Salt Reactor Initiating Event and Licensing Basis Event Workshop Summary

Oak Ridge National Laboratory (ORNL) hosted a workshop on identifying potential initiating events for radioactive releases as precursors to licensing basis events for a generic liquid-fuel molten salt reactor (MSR). The workshop was held on May 21 and 22, 2019. Participants included representatives from seven prospective reactor vendors, industry bodies, US and Canadian regulators, US and Canadian national laboratories, and the academic community. Accident sequence evaluation is central to deterministic and risk-informed performance-based reactor safety evaluation processes, and initiating events begin the accident sequence evaluation process. The workshop focused on how MSR initiating events feed into the risk-informed, performance-based reactor safety evaluation process described in DG-1353. This report describes the workshop activities and results, provides a generic list of initiating events involving selected systems, and presents the estimation of the relative frequency and consequences of accident sequences for a few important, high-level initiating events.