Bulging canisters of plutonium that could rupture and leak have not been adequately monitored at the Hanford nuclear reservation in Washington state, an independent safety panel warned.
The Defense Nuclear Facilities Safety Board contends Hanford managers have pushed their luck at the Plutonium Finishing Plant, where the canisters are stored.
The canisters bulge when air mixes with the plutonium inside what are supposed to be sealed stainless-steel containers.
Rustlike plutonium oxide forms on the plutonium metal, and the oxidation can bend and crack the canister.
In the past 10 years, two-thirds of the canisters -- the actual number is classified -- have not been checked for the weight gains that would indicate oxidation is occurring, according to a Feb. 25 defense board memorandum.
Plutonium-laced emissions from a cracked container could contaminate workers and the storage vault, creating possible health hazards and delays in plans to convert 4.4 tons of scrap plutonium into safer forms by mid-2004.
"We're not finding anything so far that is causing us extraordinary concern," said George Jackson, vice president for nuclear materials stabilizations at Flour Hanford, the main contractor at the government site.
Hanford was established as part of the secret Manhattan Project to build an atomic bomb during World War II.
Today, the mission at the 560-square-mile site is cleaning up the radioactive and hazardous waste created during 40 years of plutonium production for the nation's nuclear arsenal.