Honeywell Metropolis Works suffers another leak

The US Nuclear Regulatory Commission has launched a special inspection at Honeywell Metropolis Works in Illinois to assess a uranium hexafluoride leak that occurred during maintenance activities at the uranium conversion facility on 1 August.

The US Nuclear Regulatory Commission (NRC) has launched a special inspection at Honeywell Metropolis Works in Illinois to assess a uranium hexafluoride (UF6) leak that occurred during maintenance activities on 1 August. The Metropolis uranium conversion facility had declared an alert, the lower of the NRC's two emergency classification levels for fuel facilities, at 5:55pm that day.

The Metropolis Works (Image: Honeywell)

The Metropolis plant is owned and operated by Honeywell. It converts uranium oxide powder into gaseous UF6 suitable for enrichment, which is then marketed by Converdyn, a joint venture of Honeywell and General Atomics.

In a statement yesterday, the NRC said Honeywell had reported that a valve installed during maintenance activities had begun to leak. No one at the facility was injured and the company reported that no material was released past the site boundary, the NRC added. The leak - on the sixth floor of the plant's Feed Materials Building - was reported to have been stopped at 7.48pm.

The facility's mitigation towers, which are large water sprays, were activated, and according to Honeywell, no UF6 left the plant site. Monitoring devices located at the site boundaries detected no radiological release beyond regulatory limits.

Victor McCree, the NRC's Region II administrator, said that while no workers were affected and there was no offsite release, any release of UF6 is a potentially serious event.

The special inspection will look at: the sequence of events leading up to the release; verify that the company followed its procedures for mitigating the release and notifying local and state agencies; verify the initial information indicating that the material remained within the plant boundary; and assess the performance of the plant's detection and sampling systems. NRC inspectors will also review any corrective actions the company has taken or is planning to take.

A senior fuel facility inspector from the NRC's Region II office in Atlanta arrived at the site on 2 August. The inspection is likely to take at least a week, the NRC said, adding that a report documenting the findings will be issued within 45 days after the inspection is completed.

The plant also suffered a leak on 26 October last year, which plant operators said was contained by prompt action including water sprays. Honeywell said then that the incident followed "an apparent equipment failure in the main production building". The NRC later said it had occured on the fourth floor of the Feed Materials Building.

The NRC then formally acknowledged that Honeywell Metropolis Works had satisfactorily met all of its commitments in a list of actions required by the regulator in response to the leak in October. Production had resumed at the plant earlier that month but was stopped in early January for a planned 90-day routine maintenance outage.

UF6 production was restarted in April, but targets have been aligned with reduced customer demand. Plant owner Honeywell has said it plans to invest $17.5 million in capital and safety improvements at the plant during 2015, including a new liquid hydrogen storage facility enabling it to eliminate the use of anhydrous ammonia on site.

Honeywell International director of external communications Peter Dalpe said in a statement, "Honeywell takes this incident seriously and is cooperating fully with the NRC inspection. The NRC and other regulatory agencies were alerted to the incident promptly and the plant's emergency equipment and response teams worked as designed to contain and stop the leak without injuries." He added, "The company has made numerous improvements to its emergency response procedures over the last several years and continues to invest significantly in upgrades to the plant, including more than $60 million in projects that directly support health, safety and the environment."

Researched and written
by World Nuclear News