Toward a Generic PRA Framework for Sodium Fast Reactors: A Comparative Review of Four Pool-Type SFR Designs

With renewed interest in sodium fast reactors (SFRs) and several designs now in licensing and construction, a systematic comparison of probabilistic risk assessment (PRA) features across SFR designs is valuable to both the technical community and PRA practitioners. This paper reviews four pool-type SFR reference designs: the Experimental Breeder Reactor II (EBR-II), the Power Reactor Inherently Safe Module (PRISM), ARC-100, and Natrium. It compares technical parameters, system architectures, safety features, and initiating events, identifying common characteristics that simplify PRA modeling relative to light-water reactors and key differences that require design-specific treatment. Based on the comparison, the paper proposes a generic design envelope, a safety-function structure, generic initiating-event families, and an event-sequence framework organized around protected, unprotected, and radionuclide-barrier response, with configurable modules for design-specific features. This structure is the foundation for a future generic pool-type SFR PRA model, developed in conformance with ASME/ANS RA-S-1.4-2021 and consistent with the Licensing Modernization Project methodology.