The US Nuclear Regulatory Commission (NRC) inspected Metropolis Works as part of a comprehensive assessment being conducted for all nuclear-related facilities in the country in wake of Fukushima disaster in Japan in 2011.

Prior to Fukushima, Honeywell initiated an integrated safety analysis as part of its licensing process, and identified upgrades to the uranium conversion facility to withstand a major seismic event including seismic hardening of buildings and piping.

Honeywell noted that it will not restart production at the facility, which is currently under annual maintenance since May, until an agreement is reached with the Commission related to the upgrade projects and timing.

The timeline for the restarting of operations and the nature and timing of the upgrades has not been determined, while the company anticipates that completion of upgrades to the facility could take about 12 to 15 months.

the Metropolis Works facility plant manager Larry Smith said, "We are continuing to discuss the necessary plant upgrades with the NRC, and we hope to quickly establish a definitive timetable."

The Metropolis plant processes a variety of products, but about 80% of the work involves refining raw uranium ore into uranium hexafluoride.