Elevated levels of radioactive contamination were found last month on transuranic waste drums awaiting shipment from the Energy Department’s Oak Ridge Site in Tennessee to the Waste Isolation Pilot Plant in New Mexico, according to a recent update from the Defense Nuclear Facilities Safety Board (DNFSB).
“The contamination readings were due to the decay of Radium-226 to polonium and lead that settled on the exterior of drums,” the DNFSB said in its site report, dated June 14 and posted online earlier this month.
To avoid such contamination in the future, staff at the Transuranic Waste Processing Center plan to wipe down the outside of the drums “and perform smears on all drums prior to loading” in shipping containers for the journey to New Mexico, the DNFSB said.
The Energy Department said Friday the problem isn’t all that unusual and fairly simple to remedy. Some drums at the Transuranic Waste Processing Center have “a considerable amount of Radium-226, which decays into Radon gas,” a DOE spokesperson said via email. All of the center’s drums headed to WIPP have vents to allow release of gases as the contents decay.
“Due to these drums’ time in storage, awaiting shipment, the vented Radon gas gradually accumulated on the exterior surfaces,” the DOE spokesperson said. Since June 5, staff has been decontaminating the drums before shipment.
All drums headed from Oak Ridge meet WIPP’s waste acceptance criteria, the DOE spokesperson added.
The brief DNFSB update did not indicate how many drums had the contamination problem or when they were shipped. The board provides recommendations and advice to the Energy Department on health and safety issues across the defense nuclear complex.
Oak Ridge has made 20 shipments to WIPP so far this year, including nine during May and June.
