The U.S. Nuclear Regulatory Commission (NRC) is issuing a draft report, titled Consequence Study of a Beyond-Design-Basis Earthquake Affecting the Spent Fuel Pool for a U.S. Mark I Boiling Water Reactor (also referred to as the Spent Fuel Pool Study).
The purpose of this study, which is now up for public comment, was to examine if faster removal of older, colder spent reactor fuel from pools to dry cask storage significantly reduces risks to public health and safety, the NRC said in a notice to be published in the July 2 Federal Register.
Based on previous research showing earthquakes present the dominant risk for spent fuel pools, the draft study evaluated how a potential pool leakage from an unlikely severe earthquake might cause the used fuel to overheat and release radioactive material to the environment.
This study provides publicly available consequence estimates of a hypothetical spent fuel pool accident initiated by a low likelihood seismic event at a specific reference plant. It compares high-density and low-density spent fuel pool loading conditions and assesses the benefits of post-9/11 mitigation measures.
Past risk studies have shown that storage of spent fuel in a high density configuration is safe and risk of a large release due to an accident is very low. “This draft study’s results are consistent with earlier research conclusions that spent fuel pools are robust structures that are likely to withstand severe earthquakes without leaking,” the notice said. “The NRC continues to believe, based on this study and previous studies that spent fuel pools provide adequate protection of public health and safety. The study’s results will help inform the Commission’s evaluation of whether expedited movement of spent fuel from spent fuel pools to dry storage sooner than current practice provides a substantial increase in safety.”
The insights from this analysis will inform a broader regulatory analysis of the spent fuel pools at all U.S. operating nuclear reactors as part of the NRC’s Japan Lessons-learned Tier 3 plan.