Nuclear wasteOperations at a New Mexico nuclear waste repository suspended because of leaks

Operations at the Waste Isolation Pilot Plant, or WIPP, a New Mexico burial site for military nuclear waste, were suspended for the fourth day, the Department of Energy said, after sensors picked up radiation leaks inside salt tunnels where the radioactive material is entombed.

The Los Angeles Times reports that employees at the site, followed procedure by activating air filters and barring personnel from entering the 2,150-foot-deep waste repository.

Radiation sensors first picked up the leak at 11:30 p.m. Friday.

Officials said no radiation escaped to the surface.

“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.”

It is not immediately clear how long operations at the repository will be suspended.

The halting of operations at WIPP has already affected the handling of DoD nuclear waste. The Advanced Mixed Waste Treatment Project, a federal operation in eastern Idaho which is the primary user of WIPP, said Monday that it had suspended waste shipments to the New Mexico facility.

Gill noted that this is the second time this month the facility had to suspend operations. Earlier this month operations were halted after a truck caught fire in an underground tunnel.

The Times notes that a lengthy shutdown would create a backup in the nation’s nuclear waste disposal system. For example, in 2012, the dozen or so sites handling DoD nuclear materials made 846 shipments to WIPP, or about two a day. These facilities will now store waste on site, but storage capacity is limited.

Edwin Lyman, a senior scientist at the Union of Concerned Scientists, told the Times he believed the cause most likely involved radioactive material on the outside of a container that was not properly decontaminated. Waste is typically packaged into sealed containers. Any contamination on the outside of the containers normally would be cleaned, Lyman said.

He added that a less probable cause was a radiological process inside a container that forced material out. WIPP has acceptance criteria for the waste that is supposed to prevent such an accident.

Lyman said that the intensity and range of contamination in the underground tunnels will dictate the extent of the cleanup operation necessary to get the repository back in operation. “It could be a mess,” Lyman said. “If there is airborne contamination and it involves plutonium, they are going to need to decontaminate surfaces. If it is in the ventilation system, it could have spread to other areas.”

The Times notes that WIPP is the repository for what is called transuranic waste, which includes plutonium and other artificial elements heavier than uranium. The various facilities around the country take the waste, which may include contaminated clothing, tools, wood, and put it in 55-gallon drums, and the drums are then crushed into 4-inch “pucks.” The pucks are placed into massive, lead-lined shipping containers designed to withstand highway crashes.

When the puck arrive at WIPP, they placed inside shafts within an ancient salt bed, which is supposed to collapse around the waste in the future and seal it. The operation began in March 1999 (for a detailed report on WIPP operations, see Matthew L. Wald, “Nuclear Waste Solution Seen in Desert Salt Beds,” New York Times [9 February 2014]).

For more than two decades, Congress had allocated funds to building a nuclear waste national repository in Nevada’s Yucca Mountain. Pressure from Nevada politicians and questions about the safety and capacity of the Nevada project led the Obama administration to end the Yucca Mountain project.

The nuclear waste being buried at WIPP is far less radioactive than the spent fuel from nuclear weapons which was to be buried in Nevada, but federal officials had hoped that a smooth, accident-free record of operation at WIPP would go a long way to generate support for a more ambitious, high-level repository which would offer an alternative to the Yucca Mountain repository.

“It hasn’t been a good month for WIPP,” Lyman told the Times.