The US Nuclear Regulatory Authority (NRC) has authorised the restart of the research reactor at the Department of Commerce’s National Institute of Standards & Technology (NIST) Centre for Neutron Research (NCNR) in Gaithersburg, Maryland. The facility has been shut down since February 2021, when an event damaged a reactor fuel element without affecting public health and safety. “We’ve reached this decision after extensive review of the event, NIST’s corrective actions, and additional work the facility has done to ensure safe operation,” said Andrea Veil, director of the NRC’s Office of Nuclear Reactor Regulation.

She added: “We’re satisfied this research facility’s important systems and components are ready to go, and we’re satisfied the reactor staff are ready to carry out improved procedures for maintaining safety. We’ll continue our increased oversight of the facility and its ongoing corrective actions.” NRC approval was required before the facility could restart the reactor because the facility had violated the fuel cladding temperature safety limit. T

NRC’s technical evaluation report included:

  • review of the facility’s systems to verify there was no adverse impact from the event;
  • NIST’s actions to comply with the Confirmatory Order issued in August 2022; and
  • results from follow-on NRC inspections.

NIST’s remedial actions covered several areas including:

  • fuel handling and related management activities;
  • the facility’s safety culture and corrective action programme; and
  • the facility’s emergency response resources and procedures.

NRC also separately reviewed and approved several amendments to the facility’s licence that were requested by NIST to support the safe restart of the facility.

Following the alert, NIST conducted an internal investigation and identified the root causes of the incident which was submitted to NRC in two reports. The root causes were:

  • The training and qualification programme for operators was not on par with programmatic needs;
  • Written procedures did not capture necessary steps in assuring fuel elements were latched in place;
  • Procedural compliance was not enforced;
  • The equipment and tools used to determine whether fuel elements were securely latched in place were inadequate;
  • Management oversight of refuelling staffing was inadequate;
  • The NCNR’s change management programme was insufficient; and
  • The reactor operations group had a culture of complacency.

Image: NIST's Center for Neutron Research, in Gaithersburg, Maryland, US (courtesy of NIST)