By George Lobsenz
The National Nuclear Security Administration (NNSA) has approved safety analyses for Los Alamos National Laboratory’s plutonium facility that allow accidents that could result in worst-case radiation exposures to the public exceeding Energy Department guidelines limiting such potential doses to 25 rems, according to the Defense Nuclear Facilities Safety Board.
In a Monday letter to Deputy Energy Secretary Daniel Poneman, the federal safety board said the action by the National Nuclear Security Administration (NNSA), DoE’s semi- autonomous nuclear weapons agency, in regard to Los Alamos’ Technical Area 55 is “fundamentally in conflict with the board’s understanding” of DoE safety policies put in place 15 years ago.
The board, which provides independent oversight of nuclear safety at DoE sites, noted that DoE’s so-called “evaluation guideline” for public protection called for limiting potential accident-related doses to the public to 25 rems. In addition, the board, known as the DNFSB, said the DoE public protection standard called for operators of DoE nuclear facilities to install safety equipment and take other steps to ensure potential doses to the public at site boundaries were limited to “a small fraction” of the 25-rem evaluation guideline.
However, the board said DoE and NNSA are “essentially nullifying” those public protection standards by allowing new “safe harbor” exemptions for DoE facility operators that effectively permit them to forgo installation of expensive safety equipment to mitigate potential doses to the public above 25 rems.”The Defense Nuclear Facilities Safety Board is concerned that a recent regulatory interpretation by the Department of Energy of [the department’s nuclear safety management regulations] undermines the principles of providing adequate protection of the public, workers, and the environment from DoE’s defense nuclear facility operations,” the board told Poneman in a letter demanding DoE clarify its position on the issue.
“Specifically, the NNSA has recently approved documented safety analyses in which the mitigated dose consequences to the public exceed DoE’s evaluation guideline. Such approval implies that exceeding the evaluation guideline is an acceptable outcome of the prescribed safety analysis and control selection process.”
The DNFSB said it was concerned that DoE officials appear to have endorsed NNSA’s use of the “safe harbor” exemptions to allow potential accident-related doses from Los Alamos’ plutonium facility to exceed the 25-rem guideline for protecting the public.
Specifically, the board said that in discussions with the DNFSB, DoE officials appeared to back a white paper by NNSA’s chief of defense nuclear safety outlining how the safe harbor exemption was applied at Los Alamos–and how it might be applied at other NNSA or DoE facilities–to allow doses to the public exceeding DoE’s protection standard, which is known as Standard 3009.
“The expectations outlined in the white paper, presented by DoE and NNSA personnel during extensive discussions, and evident (for example) in NNSA’s approval of the documented safety analysis for Technical Area 55 at Los Alamos National Laboratory are fundamentally in conflict with the board’s understanding of DoE’s past practices during the 15 years since DoE Standard 3009 was established, as well as the board’s explicit position as outlined in past correspondence,” the DNFSB told Poneman.
The board said the DoE standard called for operators of DoE nuclear facilities to analyze possible accidents to determine potential doses to the public at the site boundary, and then to compare those doses to the 25-rem evaluation guideline. Operators then are supposed to install safety controls and equipment as needed in facilities to lower any potential doses above 25 rems.
“DoE Standard 3009 is clear about the application of the evaluation guideline and the fact that its [25-rem] value is not considered an acceptable public exposure; rather, its use sets a clear guideline for establishing when to invoke an effective set of safety class controls that reduce the potential dose consequences to the public to acceptably low values, referred to as a ‘small fraction of the evaluation guideline.’
“By accepting documented safety analyses with calculated mitigated consequences greater than the evaluation guideline, DoE is essentially nullifying the consequence-based methodology established by [DoE safety regulations] and evident in DoE’s practices since DoE issued the rule,” the board said.
DoE and NNSA officials had no immediate response to the DNFSB’s letter.
The 25-rem public protection standard is five times as high as the five-rem annual limit that DoE sets for doses to its nuclear workers. The average person receives 36 rems from everyday radiation sources, such as dental x-rays, radon gas from soil or cosmic rays.
The DNFSB did not say what specific Los Alamos facility was involved in the NNSA’s action to allow potential doses about 25 rems, nor what accident scenario might cause such doses.
However, in a Jan. 15, 2010, memo to DNFSB headquarters, DNFSB inspectors at Los Alamos said Los Alamos National Security LLC, which operates the New Mexico weapons lab for NNSA, had submitted a safety analysis to NNSA to justify operations past 2010 at the aging Chemistry and Metallurgy Research (CMR) Building, and that one earthquake accident scenario resulted in potential doses to the public exceeding the 25-rem evaluation guideline.
“The scenario with the highest mitigated offsite dose consequence and only mitigated consequence that exceeds the DoE evaluation guideline is for a seismic collapse and fire, with an offsite dose of approximately 36 rem[s],” the memo said.
DoE is making upgrades to the CMR building to address the earthquake/fire scenario, but the memo indicates controls will not be sufficient to all potential offsite doses below 25 rem.
The department is moving to replace the CMR, but NNSA officials say continued operations at the facility are vital to nuclear weapons and nonproliferation programs. NNSA also has been reluctant to make expensive safety upgrades at the existing CMR building because it is scheduled to close down eventually.