[UPDATED] The Nuclear Regulatory Commission said Monday it had ordered a special inspection of Honeywell's Metropolis Works in southern Illinois after a nearly two hour leak of uranium hexafluoride on Saturday evening that the company say did not endanger the public or workers at the plant.
Peter Dalpe, Honeywell's director of External Communications, said the company "takes this incident seriously and is cooperating fully with the NRC inspection." The company promptly alerted regulatory authorities that an incident had taken place. "The plant's emergency equipment and response teams worked as designed to contain and stop the leak without injuries," Dalpe said in a response to Nuclear Street's article on the leak. "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," said Dalpe.
The NRC said the facility issued an Alert at 5:55 p.m., Central Daylight Time, due to a leak of the chemical through a valve installed during a maintenance process on Saturday.
"The uranium conversion facility declared an Alert, the lower of the NRC’s two emergency classification levels for fuel facilities, at 5:55 p.m. CDT on Saturday. Honeywell reported that a valve installed during the maintenance activities had begun to leak,” the NRC said in a news release.
The leak was reported to have been stopped at 7:48 p.m. CDT. An NRC inspector was on site by Sunday, the NRC said.
Honeywell officials indicated that the leak was on the sixth floor of the plant’s Feed Materials Building. The facility’s mitigation towers, which are large water sprays, were activated, and according to Honeywell, no uranium hexafluoride left the plant site. Monitoring devices located at the site boundaries detected no radiological release beyond regulatory limits.
Nonetheless, NRC Region II Administrator Victor McCree called the incident “a potentially potentially serious event.”
The special inspection is expected to take about a week. That is followed up with a report that is issued 45 days after the inspection is completed.
"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. The NRC inspectors will also review any corrective actions the company has taken or is planning to take."
Uranium hexafluoride, used to make fuel for nuclear plants, is highly corrosive and toxic. It reacts violently with water, to the point it can react to moisture in the air.
The conversion facility has experienced other problems in the past. These resulted in releases of uranium hexafluoride in December 2008, December 2010 and October 2011. For those three releases, the facility was assessed a fine of $90,000 in December 2013.
Yet another release was reported in October 2014. That leak, which included an apparent gas plume released into the atmosphere, was filmed by workers who were picketing outside the building, The Southern Illinoisan reported.