After a radiation leak, the Energy Department suspended normal operations at its New Mexico burial site for defense nuclear waste.
Officials at the site, known as the Waste Isolation Pilot Plant, or WIPP, activated air filters as a precaution and barred personnel from entering the 2,150-foot-deep repository as they investigate what caused the leak. Radiation sensors sounded alarms at 11:30 p.m. last Friday, when no workers were in the underground portions of the plant.
Officials at the site discounted any effect on human health, saying no radiation escaped to the surface. But they said little about the extent of the problem or how they would clean it up.
“Officials at WIPP continue to monitor the situation,” spokeswoman Deb Gill said. “We are emphasizing there is no threat to human health and the environment.”
How long officials will keep the repository closed and the effects on the defense nuclear cleanup program remain uncertain.
The Advanced Mixed Waste Treatment Project, a federal operation in eastern Idaho that is the biggest user of WIPP, said it had suspended waste shipments.
Gill said the repository shutdown occurred earlier this month after another incident in which a truck caught fire in an underground tunnel. That matter is still under investigation.
Any prolonged shutdown could cause a backup of waste at a dozen nuclear-weapons-related sites across the nation, including Lawrence Livermore National Laboratory in the Bay Area. In 2012, those dozen sites made 846 shipments to the dump, more than two per day. A spokesman at the Idaho operation said it was continuing normal business and storing the waste on site.
WIPP officials have said little about what could have triggered the radiation leak.
WIPP is the repository for transuranic waste, which includes plutonium and other artificial elements heavier than uranium. In Idaho, for example, contaminated clothing, tools, wood and paper end up bundled in 55-gallon drums, then crushed into 4-inch “pucks.” The pucks go into massive, lead-lined shipping containers with 3-inch-thick tops and bottoms designed to withstand highway crashes.