An Integrated Safety Assessment Methodology for Advanced Small Modular Reactors

Abstract

Generation IV systems adopted ambitious safety objectives to drive research and emphasized the principle of defence-in-depth and risk assessment. The Integrated Safety Assessment methodology (ISAM) applies qualitative tools like Phenomena Identification and Ranking Table, Qualitative Safety Features Review and Objective Provision Tree early in the design to identify design vulnerabilities and drive research. Other quantitative tools like deterministic analysis and probabilistic assessment advance the reactor design toward licensing. This integrated safety approach iteratively guides the design improvements early on and facilitate necessary improvements through Research and Development (R&D) activities. Along with ISAM, five other methodologies are available to Small Modular Reactor (SMR) designers: INPRO safety methodology; SARGEN_IV methodology; HARMONICS methodology; ELSMOR and the Risk-informed Performance-based (RIPB) methodology.

This paper aims to provide a detailed description of the available integrated safety assessment methodologies, provide a critical evaluation of the advantages of the methodologies to help design engineers perform risk-informed assessments. This is expected to provide performance-based evidence, from the pre-conceptual to the final design stage using an iterative, thorough, progressive, tolerant, forgiving, and balanced safety approach.