A Risk-Informed Framework for Small Modular Reactor Fuel Qualification and Safety Margin Evaluation

Abstract

Fuel qualification (FQ) and safety margin evaluation are required for the development and licensing of a reactor technology. The methodologies, which have been applied to conventional water-cooled reactors to meet those requirements, may not be fully applicable to small modular reactor (SMR) technologies that typically incorporate innovative fuels and safety features. This paper proposes a new approach for FQ that can be applied to both water-cooled and non-water- cooled SMRs. As an application of the new FQ approach and based on fuel safety limit acceptance criteria, a new risk-informed framework is developed for quantification of fuel safety margins. The framework integrates the processes of FQ, reactor design development, and regulatory deterministic and probabilistic safety analyses. Three new concepts, named “deterministic safety margin fraction,” “probabilistic safety margin fraction,” and “risk fraction” are created to enable quantification in this framework. The new FQ approach and risk-informed framework are minimum measures of an SMR design to meet the regulatory safety requirements.