Production resumes at Metropolis

Full production has resumed at Honeywell's Metropolis uranium conversion plant in Illinois after a uranium hexafluoride (UF6) leak earlier this month. The leak was caused by over-pressurization of a system that was undergoing maintenance at the time.

Honeywell said that it had completed its root-cause investigation of the leak, which occurred on 1 August, and shared the results with the US Nuclear Regulatory Commission (NRC). A number of immediate corrective actions to prevent such an incident in the future have been taken and have been reviewed with the NRC, the company said in a statement.

A total of 12.04 pounds of UF6 were released as a result of the leak, which converted to 2.41 pounds of hydrofluoric acid when it was exposed to air. Putting that in perspective, Honeywell said that the amount of UF6, had it been in the liquid state, would be equivalent to "a little over 4 cups" of material. The state of Illinois only requires plants to report releases over 100 pounds of hydrofluoric acid.

In the days following the release the NRC initiated a special inspection tasked with looking at the sequence of events leading up to the release and verifying that procedures for mitigating the release and notifying local and state agencies had been followed, as well as verifying the initial information indicating that the released material had remained within the plant's boundary. The inspection also assessed the performance of the plant’s detection and sampling systems.

Honeywell said that the company is "committed to the safe operation of the plant" and continues to "review the incident and make improvements to the operations and its response as needed."

The Metropolis plant also suffered a leak of a small amount of material in October 2014, caused by a mechanical equipment failure. Production resumed in mid-November after the NRC approved the steps taken by the company to enhance emergency procedures and drills. Earlier this year, the plant underwent a scheduled, extended three-month maintenance shutdown.

Metropolis is the only operating uranium conversion plant in the USA and is owned and operated by Honeywell. The plant converts uranium oxide powder into gaseous UF6 suitable for enrichment, which is marketed by Converdyn, a joint venture of Honeywell and General Atomics.

Researched and written
by World Nuclear News