By George Lobsenz

A federal safety oversight board this week warned Energy Secretary Steven Chu that “urgent” action was needed to address the risk that earthquakes could trigger fires in Los Alamos National Laboratory’s plutonium facility, potentially leading to radioactive releases greatly exceeding safety guidelines set by the department to protect the public from nuclear accidents.

In a strongly worded letter to Chu Monday, the Defense Nuclear Facilities Safety Board (DNFSB) said the department needed to take “immediate” steps to reduce the risk of earthquake-induced plutonium releases that the board said could exceed DoE’s so-called “evaluation guideline” by more than two orders of magnitude.

The evaluation guideline calls for DoE to consider safety measures when a credible nuclear accident scenario poses the risk that a person at the boundary of a DoE nuclear site could receive a dose exceeding 25 rems–far more than the typical 0.36 rem dose received by people each year from natural background radiation in the environment, such as cosmic rays and radon gas seepage from soil.

Two orders of magnitude above 25 rems would be 2,500 rems, which would be a lethal dose.

The DNFSB said fatal plutonium releases could result if earthquakes caused gloveboxes containing plutonium and furnaces in Los Alamos’ PF-4 facility to topple over, resulting in fires.

Los Alamos and the National Nuclear Security Administration (NNSA), the semi-autonomous D-E agency that oversees the department’s nuclear weapons complex, last December approved a remedial action plan that called for strengthening and reinforcing certain “high-risk” gloveboxes containing fire ignition sources so they would not tip over during earthquakes.

However, the DNFSB said its review of that safety strategy showed the seismic upgrades would not be implemented for “many years” and that the upgrades would not be sufficient to address the worst potential earthquake scenarios.

Further, the board said not all the ignition sources at the PF-4 facility were inside gloveboxes slated for seismic upgrades, meaning those fire risks would remain unaddressed.

In addition, the DNFSB expressed concern that NNSA currently was totally reliant on a “passive confinement” strategy to prevent harmful plutonium releases from PF-4 in case of an earthquake. That means plutonium releases would be contained solely by the building structure–a low-cost approach that the DNFSB has criticized as too prone to leakage through seams, doorways and small openings in the building envelope.

The board has urged NNSA to install an “active” ventilation and filtering system in PF-4 that could suck up released materials and route them to high-efficiency particulate filters that catch and immobilize radionuclides, preventing the spread of radiation both inside and outside the building.

The DNFSB said that NNSA Administrator Thomas D’Agostino in June told the board that NNSA planned to move to an active emissions-confinement strategy over a five-year period. However, the board said D’Agostino rejected some upgrades proposed to address “performance gaps” in the confinement strategy, and that NNSA would not decide until 2012 whether it needed to make expensive upgrades necessary to ensure an active emissions-confinement system would continue operating after a severe earthquake.

However, the board told Chu that “NNSA’s current safety strategy is flawed and does not obviate the need for a seismically qualified safety-class active confinement ventilation system at the plutonium facility.

“Given the magnitude of the potential consequences to the public, the board believes DoE must develop expeditiously a defensible safety strategy for seismically induced events at the plutonium facility and a credible plan for implementing this strategy. DoE’s response must include definite, measurable and immediate means to substantially reduce the potential consequences at the site boundary.

“Implementation of a sound safety strategy must be pursued on an urgent basis,” concluded the board, which added that “the severity of the problems…and the urgency to remediate them argue forcefully for the secretary” to act quickly on the issue.

In a statement, NNSA said it was reviewing the DNFSB’s letter and developing a formal response.

“Meanwhile, NNSA continues to implement its plans to improve the safety posture at the [PF-4] facility while evaluating additional opportunities for improvement,” the agency said. “NNSA has made numerous improvements in the safety posture of its plutonium operations in recent years, which include improved packaging of nuclear material, better control of combustibles, and the approval of the first comprehensive safety analysis since 1996.

“That analysis identified the need for additional facility upgrades to meet the NNSA’s safety goals. Although the analysis concluded that operations are currently safe, a more sophisticated analysis is needed to evaluate the details of all the relevant hazards in a seismic event, to demonstrate an adequate control strategy and to ensure that needed improvements are made to meet NNSA safety goals. We are working to ensure that needed improvements in both the analysis and the control strategy are made in a timely fashion.”

The DNFSB letter raises questions about whether Chu or Deputy Secretary Daniel Poneman might intervene to order faster remedial action by NNSA or Los Alamos. By law, they are the only two DoE officials with authority to issue orders to the semi-autonomous NNSA.

At the same time, Chu is limited in some degree by conflict-of-interest restrictions from making certain decisions involving Los Alamos. Chu cannot make any decisions at DoE affecting the financial interests of his former employer, the University of California, which with Bechtel Corp. leads Los Alamos National Security LLC, the contractor that operates Los Alamos for DoE.