DOE Rejects Firm Radiation Release Limit For Its Sites

BY GEORGE LOBSENZ

Despite heightened safety concerns about earthquake impacts on nuclear facilities—and new questions about its seismic analyses—the Energy Department has rejected a recommendation by a federal safety oversight board that the department establish clear requirements for its site operating contractors to prevent potential offsite radiation doses from worst-case accidents from exceeding 25 rems, the level now set by a non-binding DOE guideline.

The decision by Energy Secretary Steven Chu to reject the recommendation by the Defense Nuclear Facilities Safety Board (DNFSB) represents the first time DOE has refused to accept formal safety guidance provided by the DNFSB since the board was established by Congress in 1998 to provide independent oversight of DOE’s self-regulated nuclear operations to “ensure adequate protection of public health and safety.”

Chu’s decision also is notable in that it follows the earthquake-triggered accident at Japan’s Fukushima Daiichi nuclear power plant—and recent revelations about the large-scale radiation releases that might occur if a major temblor hit some of DOE’s older nuclear facilities, many of which date to the Cold War and are not built to modern seismic safety standards.

The earthquake issue was further sharpened earlier this month when the DNFSB revealed that DOE had recently learned of “significant technical and software quality assurance issues” with a computer program used to assess “soil-structure interaction effects” between buildings and the ground they sit upon during earthquakes. The program, which is used extensively by DOE to evaluate earthquake risks at its nuclear facilities, was found to produce “unrealistic seismic responses” by analysts at Los Alamos National Laboratory, the DNFSB told DOE in an April 8 letter in which the board asked the department to explain what it was doing about the problem.

In general, DOE addresses radiation release risks from earthquakes and other severe accident scenarios through a guideline under which its contractors are supposed to take safety measures to ensure that releases from worst-case nuclear facility accidents will not exceed 25 rems at the boundary of the DOE sites they operate.

The department for years has publicly committed to keeping any potential releases below 25 rems, which can threaten human health but which is well below radiation levels in some contaminated water discharges from the Fukushima plant.

However, the DNFSB last October questioned DOE’s commitment to meeting the 25-rem guideline at several aging nuclear facilities at Los Alamos, saying the department appeared to be “drifting away” from longstanding policies for timely compliance with the guideline.

At issue are costly fixes or operational changes that would have to be made by DOE to meet the 25-rem standard at some of its facilities that are nearing shutdown. DOE officials have been reluctant to spend millions of dollars on those obsolete facilities at the same time they are building expensive new replacement facilities.

But while acknowledging those cost concerns, the board has made known its growing unease over DOE’s broader efforts under Chu to streamline and “improve” its nuclear safety rules and regulations. Although DOE officials have contended that their efforts are designed to improve safety by getting rid of redundant or unnecessary safety rules, the board has increasingly expressed skepticism about some elements of DOE’s initiative—and the department’s willingness to face inconvenient but real safety issues.

Tensions between the department and the board heated up earlier this year when DOE officials unsuccessfully sought to squelch a DNFSB investigation into allegations by a senior whistleblower at the department’s Hanford site that safety issues were being swept under the rug in the construction of a massive radioactive waste processing facility.

The dispute over the 25-rem safety guideline appears to present an even more fundamental clash over safety philosophy between the DNFSB and DOE.

While both sides have sought to find common ground on the matter, Chu told the board in a February 28 letter that he would not accept parts of an Oct. 29, 2010, recommendation by the board in which it called on DOE to convert the 25-rem guideline to a formal requirement for its site contractors.

Chu told the DNFSB that the department planned to review the 25-rem “evaluation guideline” established by DOE’s longstanding Standard 3009, which says contractors should take additional safety measures where analyses show worst-case accidents could result in offsite radiation releases exceeding 25 rems.

However, the secretary added, “we cannot commit to the exact language prescribed in the [DNFSB] recommendation—that is placing Standard 3009 in the body of [the DOE safety] rule.”

Further, Chu made it clear that the department would not necessarily require full compliance with all elements of Standard 3009.

“As part of our review, we will update DOE Standard 3009, clearly identifying those provisions that are mandatory,” Chu told the DNFSB. “When DOE Standard 3009 is not applied, appropriate means for reviewing and approving alternative [safety and radiation management] methodologies will be established. This will assure implementation of DOE Standard 3009, where appropriate, while maintaining the flexibility to improve the standard, as needed.”

However, the board in its October recommendation to DOE said it was just such waffling by the department on meeting the 25-rem guideline that prompted the DNFSB to call for the 25-rem guideline to be made a requirement.

“DOE has chosen over the past several years to drift away from the principles that underlay the [guideline] as originally intended,” the DNFSB said in its recommendation.

“DOE’s standards-based regulatory system needs a clear and unambiguous set of nuclear safety requirements to ensure that adequate protection of the public, workers and the environment is provided,” the board told Chu.

“Further, it is imperative that DOE provide clear direction to its safety…authorities to ensure that, if nuclear safety requirements cannot be met prior to approval of a [facility’s safety posture], DOE imposes clear conditions of approval for compensatory measures for the short term and facility modifications for the longer term to achieve the required safety posture.”

The DNFSB added: “The board does not recommend lightly a change to DOE’s nuclear safety regulations…. The board has chosen to recommend a rule change because this action would tend, in the long run, to prevent future shifts in DOE safety policy that would once again have to be challenged and argued against.”

The board issued its recommendation after learning that safety analyses for five facilities at Los Alamos National Laboratory—including two vital but aging plutonium facilities—showed that the public might be exposed to accident-related doses far exceeding the 25-rem guideline.

In addition, DOE’s Office of Environmental Management acknowledged to the DNFSB that safety analyses for its high-level radioactive waste storage tanks at the department’s Savannah River Site in South Carolina show earthquake accident scenarios could lead to offsite radiation doses to a “maximally exposed” member of the public above 25 rems.

The board’s recommendation specifically stemmed from its objection to a December 2008 decision by the National Nuclear Security Administration (NNSA), DOE’s semi-autonomous weapons agency, to approve a safety assessment for Los Alamos’ PF-4 plutonium facility even though calculations for various earthquake accident scenarios showed exceedances of the 25-rem guideline.

DOE subsequently took action to address those exceedances, but a June 2010 analysis by the department still found doses from an earthquake-induced fire scenario at 110 rems.

The department promised further actions to reduce that exceedance at PF-4, but said it planned no similar action at other Los Alamos facilities where projected doses were above 25 rems because those facilities were expected to shut down soon, making costly modifications a poor use of taxpayer dollars.

For example, NNSA told the DNFSB in a June 30, 2010, memo that despite a possible 302-rem worst-case offsite exposure from a fire in a waste storage dome at Los Alamos’ Area G—and a 1,795-rem estimate for an airplane crash into a dome—“Area G is a limited-life facility and major facility upgrades to mitigate these scenarios are not anticipated.”

(Article reprinted here by permission.) © 2011 IHS Global Inc.