The Metropolis uranium conversion plant will resume production in June 2013 when post-Fukushima safety upgrades should be completed at the facility, plant operator Honeywell announced. The plant has been offline since May.

In common with all US nuclear facilities, the Metropolis plant has been subjected to a post-Fukushima safety review by the Nuclear Regulatory Commission (NRC) to examine its readiness for extreme external events such powerful earthquakes or tornados. This process uncovered some safety issues not identified in previous regular NRC checks of the chemical plant’s operation. These inspections took place during the plant’s annual maintenance outage, which began on 9 May. Although annual maintenance activities have been completed, Honeywell has committed to keep Metropolis offline until the NRC’s requirements were met. In the meantime, the usual workforce of 332 has been reduced by about half.

Honeywell announced that it has now begun the necessary upgrades at Metropolis. This upgrade work includes seismic hardening of buildings and piping at the facility. Metropolis will also upgrade its emergency planning and notification procedures, as required by the NRC. Converdyn – which operates Metropolis on behalf of its two 50% owners, Honeywell and General Atomics – expects the plant to restart production in June 2013. However, the company noted, “As with any major capital project, the timing of any restart and worker recall could be adjusted based on the progress of the work as well as industry and market conditions.”

Metropolis plant manager Larry Smith: “We have completed the extensive scoping, planning and design work and the facility has begun construction activities related to the planned upgrades. This significant investment in the plant, in addition to the investments the company has made over the past five years, will help ensure the safe operation of the facility.”

The process to enrich uranium in fissile uranium-235 for use in nuclear fuel requires a feedstock of gaseous uranium hexafluoride. Metropolis, in Illinois, is one of a handful of plants around the world where natural uranium oxides are converted into gaseous uranium hexafluoride. Conversion plants handle only natural, unenriched uranium, and are subject to the regulations that are in effect for any chemical processing plant involving fluorine-based chemicals.

Unlike uranium conversion plants operating in Canada, France, the UK, Russia and China which all use wet chemical processes, Metropolis utilises a dry fluoride volatility process. Built in the 1950s, the plant has undergone various upgrades and expansions over the decades to reach today’s capacity of 15,000 tonnes of uranium hexafluoride per year. Conversion sales from Metropolis are handled by ConverDyn, a partnership between affiliates of Honeywell and General Atomics.