ASME/ANS RA-S-1.4 - Probabilistic Risk Assessment Standard for Advanced Non-Light Water Reactor Nuclear Power Plants

ASME/ANS RA-S-1.4 - 2021 is a joint ASME/American Nuclear Society (ANS) standard that provides requirements for Probabilistic Risk Assessment (PRAs) used to support risk-informed decisions in commercial nuclear power plants. It prescribes a method for applying these requirements for specific applications in Advanced non-Light Water Reactor Nuclear Power Plants.

RA-S-1.4 - 2021 supersedes the 2013 version issued for trial-use and pilot application. The trial-use version was extensively piloted in the development of a number of advanced non-LWR PRAs that were under development and being built around the world.

Using established technology-neutral risk metrics common to existing light water reactor (LWR) Level 3 PRAs, this reactor-technology-neutral standard supports a diverse mixture of reactor concepts, including:

• High-temperature gas-cooled reactors (HTGRs)
• Liquid metal–cooled fast reactors
• Molten salt reactors
• Microreactors
• Small modular reactors (SMRs)