Results of a Phenomena Identification and Ranking Table (PIRT) Exercise for a Severe Accident in Molten Salt Small Modular Reactors

Abstract

Canada has attracted specific interest from developers of non-water-cooled small modular reactor technologies, including molten salt reactors (MSRs). Some research & development (R&D) is anticipated to support safety assessment and licensing of these reactors in Canada. The phenomena identification and ranking table (PIRT) process is a formalized method by which a panel of experts identifies the phenomena in a postulated scenario that are most relevant to safety and evaluates the knowledge or understanding of these phenomena. The output of the PIRT process can provide direction to a focused R&D program. This paper summarizes the results of a preliminary PIRT exercise executed by Canadian Nuclear Laboratories (CNL) for a severe accident in generic MSRs. The highest-priority R&D areas to support severe accident analysis of these reactors are identified.