IAEA CRP I31033: Severe Accident Uncertainty and Sensitivity Analyses for Reactors of PWR and SMR Types and Relevant Insights

Abstract

In 2019, the International Atomic Energy Agency (IAEA) launched the five-year Cooperative Research Project (CRP) I31033 to advance the understanding and characterization of sources of uncertainty and investigate their effects on the key figures-of-merit (FOMs) of the severe accident code predictions in watercooled reactors (WCRs). Twenty-two institutions from 18 Member States participated in the CRP and, as a result, five TECDOCs are being developed: each for WCRs of four types [PWR (inclusive of watercooled SMR design), BWR, CANDU, and VVER] and one for the QUENCH-06 experiment. Respective TECDOCs address a specific exercise and outline relevant research results pointing to best practices on the uncertainty and sensitivity (U&S) analyses of the currently available severe accident codes. For the uncertainty analysis exercise, the CRP participants defined their own analysis scope and framework, including target plant, severe accident code, accident scenario, and relevant FOMs. General conclusions were made based on the analysis of the results in view of the best-practice application of the U&S methods. Among them, this paper summarizes the main results of the U&S exercise performed for reactors of PWR and SMR types within the context of the IAEA CRP and relevant insights.