Risk-Informed Opportunities and Challenges for Microreactors

Microreactors are championing new commercial applications for nuclear power because they are potentially mobile or transportable between sites, factory fueled, highly automated, and inherently safe. These features allow microreactors to be flexible in deployment locations, including those within or very near population centers. US Nuclear Regulatory Commission (NRC) approval is required of any US commercial nuclear facility. The NRC has accepted some new risk-informed applications on topics such as siting, operator staffing, and functional containment that could be broadened and approved for some microreactor concepts. Additionally, the NRC has started rulemaking on emergency planning in ways that will be more amenable for new nuclear applications. The challenge is then to develop models and assess the risk associated with these new applications. This paper discusses some of the opportunities and challenges that are more unique to microreactors. The paper also presents an initial assessment of microreactor safety that could be used to support scoping, power level, economic, and other trade studies in support of these new commercial applications and system configurations. Finally, the paper presents a process toward a more complete and holistic safety analysis along with some identified areas of future research that will enable a sound risk-informed decision-making process and reduce regulatory uncertainty for microreactors.