US nuclear laboratory

 It could take two years or more to seal vaults at a U.S. nuclear waste dump where containers linked to a major radiation leak are stored, the Department of Energy said Friday.
The federal department has been asked by New Mexico state authorities to detail when and how to secure the more than 350 waste containers stored at the Waste Isolation Pilot Plant (WIPP), an underground nuclear waste dump in southeastern New Mexico, after investigators found the containers may be the source of a radiation leak at the facility.
The department responded Friday in a filing that it could take a minimum of about 100 weeks -- and possibly twice that long -- to seal off the suspect vaults. The filing, however, did not give much detail, saying the investigation wasn't complete and this could affect the work.
The suspect containers were shipped from Los Alamos National Laboratory, a leading nuclear weapons manufacturer in New Mexico. Investigators suspect a kind of kitty litter the lab used in the containers to absorb liquid in nuclear waste may have triggered a chemical reaction in at least one container stored at WIPP and led to the radiation leak.
The leak, discovered on Feb. 14, has kept the facility shuttered for months and exposed 22 workers to low levels of radiation. Officials said previously it could be up to three years before full operations resume.
The dump stores "transuranic waste" leftover from nuclear weapons research and testing from the nation's past defense activities, according to the Energy Department's website. The waste includes clothing, tools, rags and other debris contaminated with radioactive elements, largely plutonium.