NCNR Status Update

Photo credit: Brian Renegar
• Fission products detected in confinement 

building upon normal reactor startup 

causing reactor to automatically shut down 

• 10 staff members contaminated (sent 

home after decontamination)

• No health/safety impacts to staff, public, or 

environment

• The event posed no risk to personnel nor 

the community

• The NIST reactor will remain shut down 

until we determine the root cause of the 

failure, implement corrective and 

preventive actions, and NRC authorizes 

restart

February 3rd Unplanned Shutdown

Photo credit: Brian Renegar
Progress to Date

• Good progress on confinement building 

decontamination

• 26 fuel elements moved from vessel to spent fuel 

storage pool

Rebecca (TAS), John (uSANS), Markus 

(uSANS), and Bryan (HP) at BT5

Photo credit: R. Dimeo
Progress to Date

Phase I of incident analysis complete by NCNR 

Technical Working Group (TWG)

• Determination that safety limit (temperature) 

exceeded for a fuel element

• Direct cause: a fuel element was not latched in 

place when the reactor started up on February 3rd

• Causal factors: inadequacies in refueling 

procedures, proficiency, training, oversight, and 

tooling

• Corrective actions proposed to address the causal 

factors to ensure no recurrence Photo credit: R. Dimeo
What’s Happening Now?

• Planning for additional video inspections, 

including detailed inspections of each fuel 

element 

• Planning to offload the entire core, including 

damaged fuel element

• Planning (and procurement actions) for 

remediation (filtering) of primary coolant system

• Decontamination efforts continue in the 

confinement building

Photo credit: R. Dimeo
What’s Happening Now?

• Measurements of refueling tooling in progress

• Corrective actions in development (several 

implemented)

• Subcommittee to NCNR Safety Evaluation Committee 

convened to analyze incident response and review the 

root causes and corrective actions identified by TWG

• NIST Incident Response Team continues to meet weekly 

to coordinate the NIST-level response and incident 

follow-up

Photo credit: David Hix

NIST engineer Dan Adler using laser 

scanning arm to characterize the reactor 

index plate
What’s Next?

• Continue remediation and recovery

• Safety Evaluation Committee will complete phase II of investigation

• External assessment by subject matter experts

• Implement corrective and preventive actions

• Restore reactor to operational readiness

• Seek authorization from the NRC to restart the reactor

• Schedule user experiments
Impact

• Nearly 1⁄2 of all neutron research in the U.S. is performed at NIST

• > 3000 research participants annually

• Serve 180 universities, 50 U.S. companies, 40 government agencies annually

• > 300 publications annually

• $150K/day opportunity cost

• When NIST was operating, demand for measurement time at all neutron 

user facilities exceeded supply by more than a factor of 2
Assisting Our Users

Facilitation of beamtime and coordination of experiments 

at other neutron facilities: ORNL, RAL, MURR and ANSTO 

(exploring possibilities at PSI, J-PARC)

Assisting users with data analysis and subsequent 

publications

Education & outreach (e.g. annual summer school)

CHRNS Initiative for the Non-Equilibrium Structure of Materials is being brought forward

Production of new user software

Travel restrictions due to pandemic are major barrier for 

experiments involving sophisticated sample environments 

3d-printed multi-sample holder being prepped for an nSoft experiment (3M 

and Dow) at the Australian Centre for Neutron Scattering at ANSTO