NOTE: The NIST Center for Neutron Research (NCNR) reactor remains shut down, and all measurements confirm that the public and environment have remained safe during and after the Feb. 3 alert.
Following an initial review of the interior of its research reactor, NIST has reported to the Nuclear Regulatory Commission (NRC) that a single fuel element is damaged and that on Feb. 3, 2021, a portion of the element likely exceeded a 450 degree Celsius safety limit set by the NRC. The reactor remains shut down, and the fuel temperature is at shutdown temperatures.
The license to operate the reactor granted by the NRC is based on a safety analysis that included a fuel failure of this type. This means that NIST and the NRC previously concluded that if this fuel temperature safety limit was exceeded, the public would remain safe.
Based on this new information provided by NIST, the NRC will post an event report on its website. NIST will continue its investigation and submit a written report to the NRC within 14 days.
The research reactor will remain shut down while NIST continues to investigate the root cause of the Feb. 3 event and begins to plan corrective actions. NIST will continue to work closely with the NRC throughout this process to seek authorization for the restart of the reactor.