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An independent federal safety board that monitors nuclear facilities has concerns that the Department of Energy is no longer interpreting a key safety standard as they have agreed to do in the past.
The issue is related to a safety analysis, known as “the safe harbor methodology” and its application at Los Alamos National Laboratory’s Plutonium Facility.
On Monday, the Defense Nuclear Facility Safety Board wrote a letter to Deputy Energy Secretary Daniel Poneman. The letter expresses reservations about a disagreement having to do with how to handle conditions under this rule, DOE Standard 3009, which the letter indicated has been the subject of recent discussions with the department.
The outcome of those meetings expressed in a white paper developed by the National Nuclear Security Administration nuclear safety chief “are fundamentally in conflict with the board’s understanding of DOE’s past practices during the 15 years since Standard 3009 was established as well as the board’s explicit position as outlined in past correspondence,” DNFSB Vice Chairman John E. Mansfield wrote to Poneman.
“The strength of the nuclear safety rule is that you do an analysis of all the hazards and then identify those safety controls that will reduce the risks to meet the evaluation guidelines,” said Peter S. Winokur, a safety board member.
The Los Alamos National Laboratory Communications Office referred calls to NNSA headquarters in Washington. A spokesman for the National Nuclear Security Administration said the department had received the letter and was evaluating the concerns raised.
“We recognize that the safety of the public, our workers and the environment is critical to the accomplishment of our national security mission and that appropriate use of our safety guidelines is key to our safety strategy,” said NNSA spokesman Damien LaVera. “After our review is complete, we will provide the answers that the board has requested.”
Last year, laboratory officials identified a set of circumstances at the plutonium facility that could potentially endanger the public outside LANL’s perimeter. A worst-case scenario, involving an earthquake and a subsequent fire at TA-55 was believed to pose an unacceptable threat to human health and safety. Large amounts of plutonium are stored at the facility, which is also the highly secured center for manufacturing nuclear triggers at the laboratory.
According to previous correspondence with the safety board, that risk was calculated at two orders of magnitude, or 100 times the current acceptable exposure to the public, which is 25 rem of radiation. Rem is a standard unit radiation used in assessing biological affects.
“The way the rule works is that when you do your hazard analysis, if the measured risk to the public is greater than 25 rem, you need to use safety class controls,” Winokur said. “You need not only to get down to 25 rem, but to a small fraction of 25 rem.”
The rule is considered fundamental because the board believes it is the best means to assure adequate public health and safety.
“We were surprised that headquarters was not committed for that to be a requirement with them,” he said. “That was our historical understanding and we no longer had the commitment from them that they considered that a requirement.”
On Feb. 23, Secretary Steven Chu responded to the board’s previous concerns acknowledging the safety problem, “from a first-floor fire following a seismic event,” as “approximately two orders of magnitude higher than our evaluation guideline for selecting safety class controls.”
Chu’s letter said the measures that were being taken would include “about a factor of 15 reduction” from the previous Documented Safety Analysis, which would mean the risk as measured in rem would still be 167 rem, more than six times the “safe harbor” limit.
“The people at LANS and Los Alamos are taking action to get it to guideline and below,” Winokur said. “They are reducing risk in the short run by containerizing the nuclear materials better and getting some of it off the site.”
In the midterm, Chu’s letter promised to strengthen the glove boxes used to work with the nuclear materials. In the long term, they are upgrading the fire suppression systems and installing active ventilation systems that will function reliably during and after an earthquake.
Greg Mello of the nuclear watchdog Los Alamos Study Group wrote in an e-mail Wednesday that it was not clear to him how the nuclear facility “can meet seismic requirements with safety class equipment and maintain an active pit production program with a lot of material out of vaults and in processes in glove boxes.”
Recent announcements about plans to reinforce the new Nuclear Facility under design as part of the nearby Chemistry and Metallurgy Research Replacement Facility indicate that an extra 225,000 cubic yards of concrete will be needed to stabilize the contents of the building against earthquake risks.
Without reinforcement, Mello questioned how the older pit-manufacturing building at the Plutonium Facility can be made safe.
“Not having safety standards, i.e. making them voluntary, is certainly one way,” he wrote.