Maximizing the Use of Available Weather Data to Accelerate Advanced Nuclear Deployment

Meteorological data plays a critical role in ensuring that siting decisions, licensing evaluations, and emergency preparedness plans reflect the real-world conditions that affect public health and Safety. But, the Nuclear Regulatory Commission’s (NRC) current implementation of meteorological data requirements is overly prescriptive in how data must be collected, rather than focused on whether the data ultimately provides a sufficient basis to ensure public safety.

Last week, the Breakthrough Institute shared a letter with the commission recommending steps to modernize the NRC’s approach to meteorological data requirements in reactor siting, licensing, and emergency preparedness.

Recognizing scientifically valid off-site meteorological data as acceptable is one of the most practical and impactful steps the NRC can take to shorten timelines - potentially by years - before application submission and reinforce risk-informed decision-making. Onsite data collection remains appropriate in many circumstances when a plant is operational, but the agency should make clear that alternative, technically justified data sources are fully permissible under existing rules, especially before the facility enters operation.

BTI recommends a novel approach to regulatory decision making - using a robustness metric to methodologically evaluate if a decision to allow the use of offsite meteorological data is robust when directly considering the inherent uncertainty. The existence of uncertainty is often considered to be a sufficient reason not to accept an alternative approach. However, the existence of uncertainty is only one component that should be considered in appropriate regulatory decision making, and must not be used as the sole reason for indecision or rejection. To be robust, a decision must be preferred even when the uncertainty is considered. In other words, if the regulatory decision would not change using the available offsite data with inherent uncertainty, instead of onsite data, then it is a robust choice. If the decision could, or is likely to change, then it is not robust.

Current guidance was developed for legacy technologies and does not fully reflect the safety cases or deployment realities of advanced nuclear reactors. These rigid expectations risk imposing unnecessary costs and delays without corresponding safety benefits. Updating regulatory guidance to clearly support risk-informed, performance-based use of alternative data sources to enable the safe use of civilian nuclear energy will reinforce the NRC’s commitment to flexibility and innovation, as directed by the ADVANCE Act.