Concerns that a calcium residue might be flammable prompted officials at Los Alamos National Laboratory to curtail plutonium operations and suspend waste shipments in early November, according to a federal report.
The lab suspended most waste generation and certification at its plutonium facility and halted all waste shipments after officials questioned the accuracy of documentation, particularly on how much calcium-and-salt residue remained in transuranic waste after processing, the Defense Nuclear Facilities Safety Board, an independent oversight panel, said in a Nov. 15 report that was publicly released Friday.
Calcium is used to help reduce oxidation in plutonium. Traces of the substance typically linger after processing, and if they are too high, they can ignite when exposed to open air, the report says.
The report didn’t say how long the operations and waste shipments were suspended. A lab spokesman could not comment Monday.
Officials from multiple agencies met in Carlsbad on Nov. 5 and 6 to discuss the hazard, including the National Nuclear Security Administration, Triad National Security LLC — the consortium that operates the lab — and N3B, a cleanup contractor. They concluded there wasn’t enough evidence of a flammable calcium level to keep operations suspended, the report said.
However, they decided to withhold shipments to the Waste Isolation Pilot Plant until further testing could be conducted, the report said.
The underground storage facility near Carlsbad forbids waste that has volatile chemicals mixed in.
WIPP became more vigilant about testing for flammable mixtures after a waste container was packaged in 2014 with a volatile blend of wheat-based kitty litter and nitrate salts, which caused it to explode and leak radiation. WIPP shut down for almost three years while it underwent a $2 billion cleanup.