ASME RA-S-1.4-2021

This Standard states the requirements for probabilistic risk assessments (PRAs) used to support risk-informed decisions for advanced non-light water reactor (non-LWR) nuclear power plants (NPPs) and prescribes a method for applying these requirements for specific applications. To support the application of this Standard to PRAs for a diverse set of reactor designs such as modular high-temperature gas-cooled reactors (MHTGRs), liquid metal-cooled fast reactors (LMRs), molten salt reactors (MSRs), micro-reactors and small modular reactors based on non-LWR technology, and other advanced non-LWRs, the requirements in this Standard were developed on a reactor-technology-inclusive basis. This Standard supersedes an earlier trial use version ASME/ANS RAS- 1.4-2013 [1-1]² and incorporates feedback from pilot studies using that version.