Nuclear regulators propose ending 50-year ALARA rule on radiation exposure

The Nuclear Regulatory Commission is preparing to drop a foundational radiation-protection practice known as ALARA, short for As Low As Reasonably Achievable, NPR reported.

For about 50 years, ALARA has required nuclear operators to drive worker and public doses below the stated legal limits whenever practical. The proposed rule would eliminate that requirement and create a carveout allowing higher exposures for some workers in special circumstances. Absolute dose limits would remain on the books.

The rewrite follows a May executive order from President Donald Trump directing a broad overhaul of nuclear regulation to support more reactors, including power for artificial-intelligence data centers. The order called ALARA a flawed approach to radiation risk. NRC Chairman Ho Nieh compared the old standard to telling drivers they must go as slow as reasonably achievable under a posted speed limit, arguing the ambiguity slows reactor design.

Emily Caffrey, a radiation health physicist at the University of Alabama at Birmingham, told NPR the idea behind ALARA was fair but that in practice it forced ever-stricter measures and left "reasonable" poorly defined. Edwin Lyman of the Union of Concerned Scientists warned that removing the incentive could erode practices that protected workers and the public.

High radiation doses clearly raise cancer risk by damaging DNA. At low doses the signal is harder to measure against the roughly 40% lifetime cancer rate in the U.S. population, Columbia University's David Brenner told NPR. That uncertainty is why regulators historically layered ALARA on top of hard caps.

The NRC said it is not changing its Linear No Threshold scientific model even as it proposes ending ALARA. Industry groups seeking faster licensing of new reactors argue clearer numeric limits alone would speed reviews. Communities near existing plants are watching whether workplace and perimeter monitoring habits change if the extra ALARA duty disappears.

Public comments close Aug. 31. The rule could take effect early next year.