Energy Department: Cap rather than clean up Los Alamos lab waste site

·6 min read

Aug. 1—One of Los Alamos National Laboratory's older nuclear waste disposal sites — a Cold War relic — would be capped and covered rather than cleaned up under a plan put forth by federal officials.

Known as Area C, the 73-year-old dumpsite was shut down in 1974 after taking radioactive waste, caustic chemicals, treatment-plant sludge and a variety of trash, according to records.

U.S. Department of Energy officials propose installing a 2-foot-thick, dirt-and-rock cover they say will safely contain the waste, prevent toxins from leaching into soil and groundwater, and avoid the hazards that excavating the waste would pose to workers and the environment. It also would save hundreds of millions of dollars.

A watchdog group called the plan an attempt to save money without considering the potential long-term hazards of keeping highly toxic, slow-decaying waste buried in unlined pits roughly 1,000 feet above a vital groundwater source.

"The aquifer — that's our main concern," said Scott Kovac, research and operations director for the nonprofit Nuclear Watch New Mexico. "If climate change does affect us and things start drying out, then our aquifer is going to be even more important than it already is. We have to do everything to protect our aquifer that we can."

While officials estimate the cover will last up to 1,000 years, the buried plutonium waste has a half-life of 24,000 years, Kovac said, citing Nuclear Regulatory Commission data.

One historic record indicates the site contains discarded uranium, which has a half-life of 4.5 billion years.

This proposal raises concerns it could pave the way for capping the much larger Area G dumpsite, which contains a vast amount of legacy nuclear waste that is requiring a decadeslong cleanup, Kovac said.

Because of possible impacts on natural resources, the state Environment Department has the final say. It will will review the plan to determine whether it's a viable solution or whether the Energy Department should make adjustments or seek another remedy.

The Environment Department's chosen remedy, along with arguments and evidence to back it, will be presented to the public for comment. Hearings also might be scheduled.

"It is by no means out of the question for the final remedy to change based upon public comment and/or additional evidence presented at a public hearing," Environment Department spokeswoman Maddy Hayden wrote in an email.

Area C's underground entrails consist of seven pits and 108 shafts, with only 10 of the shafts filled with concrete, according to the federal report outlining the proposed cap-and-cover measure.

Federal officials estimate the site contains 190,000 cubic yards of varied waste, and that about 240,000 cubic yards of material would have to be removed if excavated.

Capping the site with an "evapotranspiration" cover, made of soil and rocks, would cost $12 million, versus an estimated $805 million to excavate.

An Energy Department representative insisted the recommended cover was based more on safety than cost savings.

"The first priority is the safety of site workers, the public and the environment," an agency spokeswoman wrote in an email.

The analysis weighed the risks to workers and the public if the waste was dug up, packaged and then transported through local communities for years, she wrote, adding it concluded capping was a safer option.

The cover would capture moisture from precipitation and hold it until it evaporates, preventing it from passing through the buried waste and carrying contaminants to the aquifer, she wrote. It also would act as a filter for escaping gases from a vapor plume located below the waste, she added.

Without water percolating through the waste, there is no leachate — contaminated water — created that can absorb into the soil, according to the spokeswoman.

Monitoring sensors have shown the success of these caps at Los Alamos and other waste sites in the Southwest, she wrote, adding these covers work especially well in arid environments with drier soils and higher evaporation rates.

Research also shows the growth of native vegetation on the cover further removes moisture that could cause toxic leaching, she wrote.

Kovac dismissed the notion that the waste is safer below ground than above it.

Waste "can't be too dangerous to dig up but not too dangerous to leave behind, above our aquifer," he said.

He believes the waste should be scooped out of the pits and analyzed.

Radioactive material should be sent to the Waste Isolation Pilot Plant, an underground disposal site in Carlsbad, Kovac said. The pits should be lined, just as landfills now are required to do, and the nonradioactive waste can then be reburied.

Devices should be installed directly under the pits that can immediately detect any leaking contaminants, Kovac said.

Right now, there are three monitoring wells. One is near Area C, one is 600 feet away and the other is 2,000 feet away.

These devices are designed to trace waste that has seeped 1,000 feet or more into the ground, Kovac said, making it easier for stray contaminants to be missed.

He contends saving money is a definite motive for the Energy Department to install a cover — and that it shouldn't be a concern to an agency with such a colossal budget.

The $800 million it would cost to unearth the waste, separate it and rebury it is less than the agency is spending in a year to ramp up the lab's production of plutonium triggers for nuclear warheads, Kovac noted.

The document written by a lab employee in 1974 chronicles Area C's first pits being dug in 1948. It describes the crude disposal practices of the early days that gradually evolved into safer, more sophisticated methods, with employees seeming to experiment as they went along.

It notes that an array of chemicals, including ignitable ones, were dumped there, along with uranium, radioactive debris, beta gamma waste, sludge from treatment plants and uncontaminated refuse.

Early on, workers stuffed contaminated waste into plastic bags and cardboard boxes rather than in sturdy, sealed containers, the record says.

"Inadvertently, some plutonium contaminated objects were placed in the pit but have long since been covered," it says.

It goes on to say that because of the uranium disposed of in one pit, it should be assumed this pit is mildly alpha contaminated — meaning radioactive.

Radioactive waste disposal was phased out at the site after Area G was established to take those materials. The last radioactive waste was dumped at Area C in the mid-1960s.

Kovac said given the lack of regulations governing how waste was disposed of decades ago, it's important to see what's in the pits and assess the hazards rather than simply covering them.

There's a chance that certain types of waste should not, by modern standards, be mixed together or stashed in the ground, he said. But the lab and Energy Department seem OK with not applying current environmental guidelines whenever possible, he said.

"Anything before the 1980s is grandfathered in," Kovac said.

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