Safety questions arise as Los Alamos National Laboratory pursues pit production

Lab employees’ radiation exposure limit is 2,000 millirem a year, although managers are required to take action to curb dosage when a worker’s portable detection device shows a cumulative total of 1,000 millirem.

Still, 2,000 millirem is four times the limit at Savannah River Site in South Carolina and Lawrence Livermore National Laboratory in California, according to an April 8 report by the Defense Nuclear Facilities Safety Board.

The Los Alamos lab, the report said, also “leads all sites with the highest collective worker dose and an upward trend, consistent with an expanding mission.”

But the lab’s radiation safety managers said data shows average worker exposure is less than 5 percent of the limit, and the collective doses are higher than other national labs because of the bigger workforce and the larger overall volume of radioactive materials they handle.

“An increase in the worker collective dose was anticipated given that Los Alamos has increased its plutonium operations,” said Stephanie Archuleta, the lab’s Radiation Protection Division leader. “Our doses are justified given the national security mission and work of the laboratory.”

Archuleta said the lab has a corresponding obligation to keep doses to levels as low as “reasonably achievable” through a systematic effort.

“It’s a pretty robust program,” she said, adding the lab takes the health and safety of its workers seriously.

The lab’s exposure cap is well below the 5,000-millirem occupational limit of the U.S. Energy Department and Nuclear Regulatory Commission, she said. And lab managers work to ensure employees’ radiation doses don’t reach 2,000 millirem.

One critic contends the lab still is allowing hazardous doses.

Even 1,000 millirem, the threshold that requires intervention, is the equivalent of getting 500 chest X-rays, which over the course of a person’s working life can take its toll, said Dan Hirsch, retired director of environment and nuclear policy programs at the University of California, Santa Cruz.

“There’s no safe level of radiation,” Hirsch said. “The issue is how dangerous is acceptable. The whole game is that they are allowing extraordinarily high levels of radiation exposure.”

Falling comfortably within the federal limits of 5,000 millirem means nothing because the federal government came up with this antiquated ceiling in 1960, Hirsch said.

However, Archuleta said of the nearly 9,500 workers who were monitored for external radiation exposure in 2020, more than 70 percent received no doses.

Those who received a dose averaged 92 millirem during the calendar year, she said. Typical area residents have 700 millirem exposure during a year in their daily lives from the sun, rocks, soil, X-rays at their doctors’ offices and other miscellaneous sources, she said.

All of the lab’s radiological workers are tested once or twice a year, depending on their jobs and the kinds of materials they deal with, said Jeff Hoffman, deputy division leader of radiation protection. They also are tested if there’s a radioactive release in their work area from, say, a breached container, Hoffman said.

But a watchdog group argued Los Alamos lab adopting a higher radiation limit for workers than other labs is to create more leeway when it ramps up plutonium pit production.

“The collective worker doses would probably go up once they start actual manufacturing,” said Scott Kovac, research and operations director for the nonprofit Nuclear Watch New Mexico.

Plans call for the lab to produce 30 pits yearly by 2026 to replace aging nuclear triggers — some of them dating to the 1970s — and to arm at least one new warhead in the coming decade. Savannah River Site is slated to make an additional 50 pits by the mid-2030s.

The most pits the lab has produced in a year was 11 for Navy missiles more than a decade ago.

Jay Coghlan, the executive director for Nuclear Watch New Mexico, said the agency in charge of nuclear security is pushing the lab to crank up pit production, yet it won’t install what’s known as a “safety class active confinement system” that would prevent a heavy radioactive release during an earthquake, catastrophic fire or a serious accident.

Coghlan pointed to a 2004 letter by the safety board urging the National Nuclear Security Administration to install the safety-class system.

“This is a longstanding recommendation that Los Alamos [lab] and NNSA refuse to honor while continually downplaying the risk of expanded pit production,” Coghlan said.

This system will continue to function during an accident, the letter states, “thereby ensuring that radioactive material is captured by filters before it can be released into the environment.”

But in an email, Gordon Trowbridge, spokesman for the nuclear security agency, wrote the upgrades being made to the existing system will “offer robust safety protection” in the rare event of an earthquake and destructive fire.

Meeting the additional technical requirements of installing a safety class system in the facility would bring “marginal safety improvements,” Trowbridge wrote.

Coghlan said he’s baffled that an agency spending $7.8 billion in the next five years to overhaul the plutonium facility to make pits can’t budget some money to ensure it’s as safe as possible. The more pits produced, the more likely a serious incident will occur, he added.

Cutting corners on the facility’s safeguards combined with adopting higher worker exposure limits shows the agency and lab put the pit mission above all else, Coghlan said.

“They are not adequately prioritizing safety,” he said.