With renewed interest in sodium fast reactors (SFRs) and multiple designs now progressing through licensing and construction, a systematic comparison of probabilistic risk assessment (PRA) relevant design features and risk assessment approaches across SFR designs is valuable for both the technical community and future PRA practitioners. This paper presents a comparative review of four pool-type SFR reference designs, the Experimental Breeder Reactor II, the Power Reactor Inherently Safe Module, ARC-100, and Natrium reactor, with the goal of informing the development of a generic SFR PRA framework.
The review systematically compares technical parameters, system architectures, safety features, and initiating events across the four designs. It identifies common characteristics that simplify PRA modeling relative to light-water reactors, along with key design differences that require design-specific treatment. Available PRA and safety analysis documentation for each design is also reviewed to characterize the current state of SFR risk modeling practice and identify areas where generic treatment is appropriate.
Based on the comparative findings, a generic design envelope, system selection, initiating events and event tree framework structure are proposed to serve as the foundation for a generic pool-type SFR PRA model, in conformance with ASME/ANS RA-S-1.4-2021 and consistent with the Licensing Modernization Project methodology.