For the second time in 11 years, a New Mexico fire is threatening one of the nation's three nuclear-weapons laboratories, as well as the town that hosts it.
The approaching Las Conchas fire is raising concerns that if the blaze reaches the lab, it could free radioactive material from the grounds and storage sites surrounding the laboratory.
The bulk of the lab's stockpile of highly-radioactive material is stored in structures specifically designed to withstand fire, lab officials say.
But the facility also hosts some 20,000 barrels of plutonium-bearing waste – ultimately destined for long-term storage in southern New Mexico – at a facility atop a small mesa just outside White Rock, N.M., known as "Area G." As of midday on Tuesday, the fire was two miles away from Area G.
The laboratory grounds also include at least one canyon that was used as a dump in the early years of the US nuclear weapons program.
Teams from the National Nuclear Safety Administration are expected to arrive on-site Tuesday, to help deal with any releases that might occur if the fire reaches the lab.
The Las Conchas fire started Saturday afternoon in the Santa Fe National Forest. The cause remains under investigation, but by Tuesday morning, the explosive blaze had scorched nearly 61,000 acres, forcing the evacuation of the Los Alamos National Laboratory, as well as the town of Los Alamos, both about 25 miles northwest of Santa Fe.
Lessons from the past: The Cerro Grande Fire
The last fire that threatened the lab, the Cerro Grande, took two weeks to burn 48,000 acres when it moved across New Mexico in 2000. That blaze caused an estimated $1 billion in damage, destroying lab buildings and some 400 family homes, but no fatalities from the fire were reported.
During the Cerro Grande fire, some forms of radioactivity increased to between two and five times their normal levels, according to a study led by lab researcher David King.
But they weren't from the radioactive materials at the nuclear weapons lab.
Instead, radioactive byproducts from naturally-occurring radon gas, which had settled on plants and the soil around the plant, got caught up by the fire and redistributed. The team calculated that, even at the height of the blaze, the firefighters and volunteers were exposed to a level of radiation far below that of someone on an airline flight.
Still, the work highlighted a lack of information on the kind of radiation released by any wildfire – a gap filled by measuring the release of radioactive particles from four experimental fires, including two controlled burns in the Carson National Forest outside of Taos, N.M., in 2001 and 2002.
Lab scientists did find elevated levels of radioactive elements in ash following the Cerra Grande fire – including isotopes of plutonium, cesium, and strontium that appeared to be residual fallout from the years prior to a ban on above-ground nuclear tests.
To deal with the run-off – an issue not just after wildfires, but an ongoing concern because of lab-produced chemical contaminants – the lab has built a low-slung rock dam across one canyon, to slow the flow of storm run-off and allow sediment to fall out behind the dam. It has also planted willows and restored wetlands in strategic locations along the courses taken by run-off.
The current concern: Power failure
In looking at the potential radiological risk from the Las Conchas fire, the biggest uncertainty rests with a broad power failure involving the lab, says Jay Coghlan, executive director of Nuclear Watch of New Mexico, a watchdog organization based in Santa Fe.
Most of the sensitive facilities are hardened and "pretty much fireproof," he says. As for the 20,000-barrel Area G storage facility, if a fire engulfs them, "the consequences are severe, but the probability is probably relatively low." The facility is not within the Ponderosa forests that are currently burning, and the lab has taken pains to clear the facility's immediate surroundings of vegetation.
But loss of power to the lab injects an extra element of uncertainty into the safety equation, Mr. Coghlan continues.
"I don't draw any parallel to Fukushima except to note that stuff happens when power goes out," he says.
Firefighters are prepared to build a line around the lab if the need arises, even as they set up containment lines to protect area homes.
In an interview Monday with the Associated Press, deputy Los Alamos County fire chief Mike Thomas said, "We'll pre-treat with foam if necessary, but we really want the buildings to stand on their own for the most part. That is exactly how they've been designed. Especially the ones holding anything that is of high value or high risk, for the community, and really, for the rest New Mexico for that matter."
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