19 May (NucNet): Workers who entered the underground facility at the US Department of Energy’s Waste Isolation Pilot Plant in New Mexico obtained visual evidence that shows a damaged waste container, identified as one from Los Alamos National Laboratory, the DOE said in a statement.
In the new pictures, the container has a cracked lid and shows evidence of heat damage, the statement said. “Workers will continue investigating to determine what caused the container breach and if any other containers were involved or damaged.”
Los Alamos, which carries out nuclear weapons research, said in a statement that it “is fully cooperating” with state and federal officials and has taken extra precautions to ensure that similar waste drums “are in a safe and controlled configuration”.
Since an incident on 14 February 2014 that resulted in the release of radioactive material, DOE and WIPP staff have been working to determine the cause of the release.
The incident happened in the underground repository at the WIPP. It resulted in the release into the environment of americium and plutonium from one or more transuranic (TRU) waste containers.
The WIPP is a deep geologic repository, mined out of a thick bed of salt, for the disposal of defence TRU waste generated primarily from the cleanup of DOE sites and from research and production of nuclear weapons.
The release was detected by an underground air monitor and then directed through particulate air filter banks in the surface exhaust building.
However, the DOE said “a measurable portion” bypassed the filters through two ventilation system dampers and was discharged directly to the environment from an exhaust duct.
The dampers were not designed to be airtight. The confinement ventilation system had been considered “safety significant” until a change in 2008 reduced its classification to “balance of plant”, meaning it was no longer considered to be needed to protect workers from radiological accidents.
A preliminary report into the incident said the WIPP contractor, DOE headquarters and the department's field office in Carlsbad, New Mexico, as well as outside organisations, missed opportunities to identify that inadequacy in the safety basis for the ventilation system.
The direct cause of the release could not be determined because of a lack of access to the underground area in question, the report said. That question will be resolved in a second phase of the board’s investigation, it said.
Twenty-one personnel initially tested positive for low level amounts of internal contamination. Trace amounts of americium and plutonium were detected off-site.
