The U.S. Nuclear Regulatory Commission has issued a Confirmatory Action Letter documenting actions that Uranium One USA has agreed to take following an incident in Canada in which three workers were exposed to yellowcake from a drum shipped from a U.S. facility.
The incident occurred on 23 June at a uranium conversion facility in Blind River, Canada. When a worker loosened a ring clamp on a 55-gallon drum containing uranium oxide yellowcake the lid blew off, ejecting about 26 kilograms of the material into the air. The worker closest to the drum and two others in the area, who were not wearing respirators, were exposed to airborne uranium. Any adverse health effects to the workers would likely be caused by chemical, rather than radiological effects, NRC said.
The barrel had been shipped from Uranium One’s Willow Creek Facility in Wyoming to a Canadian conversion facility on 29 May. Following this incident several other drums shipped to the Canadian facility containing yellowcake were found to be bulging from internal pressure.
The Canadian facility has stopped opening containers of yellowcake from Uranium One’s Willow Creek facility until they can develop a plan to safely do so. The licensee has notified the NRC that it has suspended all shipping from the Willow Creek facility until it determines how the drums became pressurized.
Under the terms of the Confirmatory Action Letter, Uranium One has agreed to investigate the cause of the event; develop a course of action to ensure the safety of any other unopened drums containing yellowcake previously shipped from its Wyoming facility; and develop a corrective action plan to ensure the safety of continued storage, shipment or further processing of the yellowcake.
After similar events occurred at several facilities in 1998, corrective actions were adopted by the industry to prevent recurrence. Specifically, new procedures were adopted to ensure that drums containing yellowcake remained unsealed for at least three hours to ensure adequate cooling of the material.
NRC said that once the licensee has completed its own investigation, the commission would conduct an inspection to independently evaluate the circumstances surrounding this event. The NRC will also review the licensee’s proposed corrective actions to ensure the facility can resume safe shipping.
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