The U.S. Nuclear Regulatory Commission (NRC) is moving to eliminate a 50-year-old radiation protection standard as the Trump administration pushes regulators to accelerate nuclear development.
NRC Chairman Ho Nieh defended the proposed change on Monday, arguing that the existing standard creates uncertainty for nuclear operators and developers.
The proposed rule would remove the “As Low As Reasonably Achievable” principle, commonly known as ALARA, from federal nuclear regulations.
ALARA requires nuclear operators to reduce radiation exposure below legal limits whenever reasonably practical. Regulators have used the principle for decades to protect nuclear workers and the public from unnecessary exposure.
However, the NRC now argues that the standard creates uncertainty because companies must determine what qualifies as reasonably achievable. The proposal forms part of President Donald Trump’s broader effort to overhaul U.S. nuclear regulation.
Trump ordered the NRC to revise its rules in May 2025 as his administration sought faster nuclear development. The administration views nuclear energy as one way to meet rapidly growing U.S. electricity demand.
Artificial intelligence data centres and industrial expansion have helped drive forecasts for substantially higher power consumption. Additionally, the administration wants regulators to make it easier for companies to develop smaller advanced nuclear reactors.
Trump’s executive order specifically criticized ALARA and described its approach to radiation risk as flawed. The NRC has not abandoned its underlying scientific model for estimating those risks.
Instead, the agency plans to retain the Linear No Threshold model while removing the separate ALARA requirement. That model assumes any amount of ionizing radiation carries some cancer risk, with risk increasing alongside exposure.
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High-dose radiation damages DNA and contributes to cancer
Scientists can clearly observe cancer effects after high radiation doses. However, researchers have much more difficulty measuring the effects of small doses against the population’s already high background cancer rate.
About 40 per cent of Americans develop cancer at some point during their lives. Consequently, researchers struggle to identify a small increase caused by low radiation exposure within such a large baseline.
Columbia University radiological researcher David Brenner said high-dose radiation clearly damages DNA and can produce cancer-causing mutations. The uncertainty becomes much greater as researchers examine progressively smaller doses.
For decades, regulators addressed that uncertainty by requiring operators to keep exposures below permitted limits whenever reasonably possible. ALARA therefore functions as an additional safety principle rather than simply another numerical exposure ceiling.
NRC Chairman Ho Nieh argues that approach now creates unnecessary ambiguity for reactor developers and operators. He recently compared ALARA with requiring motorists to drive as slowly as reasonably achievable despite having a posted speed limit.
A 55-mile-per-hour limit provides drivers with a clear number. However, an additional instruction to drive reasonably slower leaves considerable room for interpretation.
Similarly, the NRC wants nuclear operators to rely primarily on established numerical radiation limits. Current rules generally limit occupational exposure to 5 rem annually and public exposure to 0.1 rem.
For comparison, the Environmental Protection Agency estimates that a whole-body CT scan delivers roughly 1 rem. Additionally, those existing NRC exposure limits would remain unchanged under the proposed regulation.
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Critics argue eliminating ALARA weakens incentives to reduce exposures
University of Alabama at Birmingham radiation health physicist Emily Caffrey supports eliminating ALARA. She argues that the principle began as a sensible precaution but gradually encouraged increasingly stringent radiation controls.
In addition, Caffrey believes numerical limits provide clearer expectations than a standard built around differing interpretations of reasonableness. Critics argue that eliminating ALARA could weaken incentives to reduce exposures even when companies can easily do so.
Edwin Lyman, nuclear power safety director at the Union of Concerned Scientists, opposes removing the requirement. He argues that ALARA helped drive worker and public radiation exposures to very low levels.
Removing it could allow operators to treat the regulatory ceiling as an acceptable target rather than a maximum. However, the proposed rule would not increase the NRC’s ordinary exposure limits.
It would instead create a mechanism allowing some nuclear workers to receive higher doses under special circumstances. Companies could request what the NRC calls a “planned occupational dose limit extension” for specific work.
Under that provision, an eligible worker could receive as much as 10 rem during one year. The worker’s total exposure could not exceed 25 rem over five years.
Additionally, the NRC has said it expects operators to use the extension sparingly rather than as a routine staffing measure. Agency officials have identified reactor refueling and nuclear plant upgrades as possible situations where operators might request an extension.
Those jobs can require employees to work near equipment or areas with elevated radiation levels. Consequently, the exemption could give plant operators greater flexibility when completing time-sensitive maintenance or modifications.
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Trump administration presses regulators to accelerate development
Caffrey said a 10-rem annual exposure approaches levels where experts can identify an increased cancer risk. She said she would not want to receive that exposure every year throughout her working life.
However, she considers an occasional exposure at that level acceptable based on her understanding of radiation risk. Lyman takes a more cautious position because the NRC continues to accept the Linear No Threshold model.
Under that framework, lower doses still carry some risk even when studies struggle to measure the effect directly. He argues that ALARA gives companies a reason to reduce those small risks whenever practical.
Furthermore, Lyman warned that removing the principle could gradually change how regulators and the public perceive ionizing radiation. He believes the revision deemphasizes potential harm despite the agency retaining a model that assumes risk continues at low doses.
The debate comes as the Trump administration presses regulators to accelerate development of new nuclear technologies. Electricity demand has become a major policy concern as companies build power-hungry AI data centres across the United States.
Additionally, advanced reactor developers are pursuing smaller designs intended for industrial sites, data centres and other large electricity users. Nieh said eliminating ALARA could particularly benefit designers of those smaller advanced reactors.
Developers currently must account for fixed exposure limits and the broader requirement to minimize doses where reasonably achievable. Removing the second standard could simplify design decisions and regulatory reviews.
The change also fits into a wider NRC regulatory rewrite ordered by Trump. His executive order directed the commission to reconsider rules that the administration believes unnecessarily slow reactor licensing and deployment.
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Regulatory limit does not represent harmless radiation dose
Meanwhile, supporters of faster nuclear development argue that subjective requirements can add costs without delivering proportional safety benefits. Radiation protection experts remain divided over whether ALARA falls into that category.
Supporters of the revision see a vague standard layered over already established legal limits. Conversely, opponents see ALARA as an important mechanism preventing permissible exposure from becoming routine exposure.
The distinction matters because a regulatory limit does not necessarily represent a harmless radiation dose. A limit instead establishes the maximum exposure regulators normally permit under specified conditions.
ALARA has historically pushed operators to remain below that ceiling when practical. However, removing it would leave the numerical limits themselves intact.
The NRC published the proposed rule in July and opened it for public comment. The comment period runs through Aug. 31 for industry groups, scientists, workers and other interested parties.
Subsequently, the commission can consider those submissions while preparing a final version of the regulation. The revised framework could take effect early next year if the NRC adopts the proposal.
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