ROGER SNODGRASS Monitor Assistant Editor
Los Alamos National Laboratory has taken several steps to avoid further discrepancies in its nuclear waste inventory.
Lab spokesperson James Rickman said that last September laboratory personnel discovered duplicate labels in three separate incidents, which led to a wall-to-wall inventory of its transuranic waste holdings and processes.
"That revealed incidences in which waste containers that were listed in the historical database could not be located and waste containers at the site were not listed in the database," he said.
The discrepancies were reported in a field report by the site representative of the Defense Nuclear Facilities Safety Board in a memo dated May 4., which noted that LANL had reported "the results of a four-month inventory reconciliation in which 38 containers with a total of 169 plutonium-239 equivalent curies could not be accounted for."
The memo puts those numbers in perspective, by comparing them to the current above-ground inventory at Area-G, which includes roughly 20,000 containers that hold approximately 130,000 pu-239-equivalent curies.
Rickman said, the total amounted to one-tenth of the Transuranic waste at Area G.
"Area G is an access-controlled site," he said. "Only employees or subcontractors with badges can enter. Pajarito Road is behind a police-staffed entry station." These factors led the lab investigators to conclude that it was "extremely unlikely" that any waste was inappropriately handled.
More likely scenarios, he said, involve various record-keeping discrepancies, including repackaging waste from one container into one or more new containers without properly entering the data. Some waste containers may have been placed inside an "overpack" container without proper accounting and in other cases, technicians may have made errors in notation or data entry.
Corrective actions to be performed In the future, Rickman said, include quarterly spot checks of containers and monthly inventories of the storage domes, as well as spot validation of the locations of individual drums selected at random from the database. New data entry will require validation by two people.
Transuranic, or TRU waste refers to man-made radioactive wastes from elements with higher atomic numbers than uranium, of which plutonium is the most common element. The lab's waste containers are typically described as drums containing contaminated materials and equipment.
The containers are awaiting shipment to the Waste Isolation Pilot Project in Carlsbad, N.M.
The Institute for Energy and Environmental Research, a Washington, D.C. public interest organization has expressed concerns for over ten years about discrepancies in nuclear materials accounts at LANL
Responding to the most recent reports, IEER noted that despite its reports and requests to the Department of Energy, the National Nuclear Security Administration, LANL, the Environmental Protection Agency and DNFSB to account fully for discrepancies, "None of these agencies has yet undertaken a serious investigation."