The NRC is preparing to change a foundational rule designed to minimize radiation exposure. The update is part of President Trump's expansive changes to nuclear oversight, as his administration seeks to revive nuclear energy to power data centers for artificial intelligence.
Under a new proposed rule, the agency is eliminating a 50-year-old standard known as "As Low As Reasonably Achievable" (ALARA), which requires the nuclear industry to drive radiation exposure for workers and the public below the stated limits where possible. The new rule also creates a carveout for some workers to get higher exposures to radiation in special circumstances.
For some, the elimination of ALARA is overdue. "Keeping doses as low as reasonably achievable was a fair idea," said Emily Caffrey, a radiation health physicist at the University of Alabama at Birmingham. But in practice, the standard forced companies to take increasingly stringent radiation protection measures. It also created ambiguity, Caffrey said, "because what's 'reasonable' to one person isn't reasonable to another person."
But others warn that the change could lay the groundwork for higher radiation exposures.
"Removing it would remove that incentive for these companies to continue to maintain the practices that protected their workers and the public," said Edwin Lyman, director of nuclear power safety at the Union of Concerned Scientists, a watchdog group.
The public comment period for the new rule ends Aug. 31. It could go into effect early next year.
Radiation and cancer
Since shortly after the dawn of the nuclear age, scientists have been aware of the risks of radiation exposure, and decades of data makes it clear.
"At high radiation doses, nobody's really arguing radiation causes cancer," said David Brenner, director of the Center for Radiological Research at Columbia University. High doses of radiation damage DNA and can cause mutations that lead to cancer. But when the dose is low, it's much harder to determine risk because about 40% of the U.S. population develops cancer at some point in their lifetime.
"As you go down in dose, what you're looking for is a very small increase in cancer risk over a very large background," Brenner said. "That's what makes it really, really hard."
For the past 50 years or so, the Nuclear Regulatory Commission has dealt with this uncertainty by requiring that radiation exposure be kept as low as possible by asking that the nuclear industry adhere to ALARA.
Then last May, President Trump signed an executive order calling for a wholesale overhaul of nuclear regulations. The order specifically called out ALARA, claiming the principle was a "flawed" understanding of radiation risks.
The NRC decided not to change its scientific model of radiation risk, known as the Linear No Threshold model, but it has proposed eliminating ALARA.
Speaking this week on the Federal News Network, NRC Chairman Ho Nieh said that ALARA is no longer working.
To explain why, he drew a comparison to speed limits. A road's speed limit might be 55 miles per hour, but "imagine if there's another rule that says you have to drive as slow as reasonably achievable to be safer. Well, what does that mean? 50, 45, 25 miles per hour?"
That uncertainty would make it hard for drivers, and similarly ALARA is making it hard for reactor designers, Nieh argued. He said getting rid of it is part of a sweeping overhaul of many NRC rules as required by President Trump's executive order.
"The reason we're taking these regulatory reforms is because there's a demand for, an urgent demand for more electricity in the United States, due to artificial intelligence, data centers and industrial growth."
Removing ALARA will especially help the design of new, smaller reactors that could power some of these applications, Nieh said.
"Loosey-goosey" rules
The NRC will instead use the existing current threshold of 5 rem for a worker and 0.1 rem for the public as the upper limit for radiation exposure. A whole body CT scan is about 1 rem, according to the EPA.
Caffrey said she's comfortable with eliminating the squishy ALARA principle and asking the industry to stick to the numbers already in the regulations: "You should have a number because 'reasonable' is too loosey-goosey."
The proposed NRC rule doesn't change its other regulatory limits, but it does create some carve-outs. In particular, the industry would now be able to ask for a "planned occupational dose limit extension," which would allow workers to receive 10 rem instead of 5 in any given year, providing their overall exposure doesn't pass 25 rem in a five-year period.
In its public meeting on the proposed change earlier this month, the NRC said it envisioned the dose limit extension would be used sparingly for things like reactor refueling and upgrades at nuclear power plants. Caffrey says that a 10 rem exposure in a given year is getting close to the level that experts know can elevate cancer risk.
"I personally, knowing everything I know, would not want to get 10 rem every year for my working life," she said. "But occasionally, I would be OK with that."
But Lyman, with the Union of Concerned Scientists, thinks that ALARA should stay. He said while it may be imperfect, its net effect has been to reduce radiation exposure to very low levels. The harms of low-dose radiation exposure are difficult to see, but Lyman says NRC's own models suggest those harms exist.
In his opinion, the revised rule ignores that risk and is designed to desensitize the public to the dangers of radiation. "It's trying to devalue and deemphasize the harm of ionizing radiation exposure," he warned.
Contact Geoff Brumfiel on Signal at gbrumfiel.13
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