Since a 14 February radiation release at the Waste Isolation Pilot Project (WIPP), a deep geological repository for nuclear waste of military origin, exhaust air has passed through high-efficiency particulate air filters. On 30 May workers began to test ventilation fans in preparation to change the filters. This activity will take several weeks and will prevent any workers from being able to enter the shut-down repository to try to determine what caused the release.
On 14 February, a continuous air monitor at the end of the panel 7 drift went off and workers on the surface received a small radioactivity dose from contaminated unfiltered air that escaped the filtration system.
Entries into the seventh drift of waste emplacements, called Panel 7, have confirmed that at least one container from a nitrate salt-bearing waste stream from Los Alamos National Laboratory has breached.
The container breach was the most likely source of the release, according to a plan of action prepared for the New Mexico state environment department, published on 30 May. The near-term plan is to close that panel, and the adjacent one, over the next year or so. It said that investigations are continuing to determine if other containers contributed to the release. Containers in two rooms of the adjacent drift, Panel 6, also contain this kind of waste.
The document also said that the extent of contamination of the repository caused by the release is still being ascertained.
The impact of the radiation release at WIPP has been magnified by an unrelated event a week earlier, when a salt-hauling truck catching fire underground when an inflammable oil came into contact with a hot surface and injured 13 workers. A Department of Energy Accident Investigation Board report published in March found that the root cause of that incident was the failure of operator Nuclear Waste Partnership to recognize and mitigate the hazard of a fire, failure to clean the truck, and the wrong decision to deactivate the automatic onboard fire suppression system.
Photo: Damaged drum in panel 7; photographs taken 22 May