DNFSB: OFFSITE EXPOSURE RISK STILL TOO HIGH AT LANL PU FACILITY

By ExchangeMonitor

Despite recent upgrades to Los Alamos National Laboratory’s Plutonium Facility, potential exposures in the case of an earthquake-induced fire still exceed Department of Energy guidelines, the Defense Nuclear Facilities Safety Board said in a recent letter to the National Nuclear Security Administration. In the sharply worded June 18 letter, DNFSB Chairman Peter Winokur said that the Board had identified “multiple, substantial deficiencies” with estimates by the lab of a potential exposure to the public, suggesting that the lab might need to do more than it has already done to shore up the facility against an earthquake followed by a fire. In the most recently revised version of the lab’s 2011 Documented Safety Analysis, which is set to go into effect June 25, the lab said that upgrades to the facility, decreases in material at risk and new calculations had lowered the total effective dose equivalent (TEDE) to 23 rem, just under the 25 rem DOE guideline.

The Board, however, suggested that the lab was not conservative enough in its calculations and that its own analysis revealed the potential exposure to be more than four times that level. The Board requested a briefing and report from the NNSA on its plans to revise the facility’s safety basis and ensure quality assurance requirements are followed in the development of safety analyses within 30 days. “The Board’s estimate of this accident’s mitigated dose consequence in excess of 100 rem TEDE accounts for conservatism in the leak path factor and respirable fraction for one material,” Winokur wrote. “Additional use of appropriately conservative parameters would further increase the dose consequence for this postulated accident.”

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