Nuclear regulator moves to drop 50-year-old radiation safety standard

The Nuclear Regulatory Commission is preparing to eliminate a 50-year-old radiation safety standard that has required the nuclear industry to keep worker and public exposure as low as reasonably achievable, a principle known in the industry as ALARA. Public comment on the proposed rule change closes August 31, according to NPR member station reporting, with implementation projected for early 2027.

The move stems from an executive order President Trump signed in May 2025 directing a broad overhaul of nuclear regulation. The order singled out ALARA by name, calling the standard’s underlying premise about radiation risk “flawed.” The NRC, an independent federal agency, is now carrying out that directive through a formal rulemaking process.

Under current rules, the numerical exposure limits are 5 rem per year for workers and 0.1 rem per year for members of the public; a single CT scan delivers roughly 1 rem. Those numerical caps would remain in place under the proposed rule. What would be removed is the ALARA requirement that plant operators take additional, ongoing steps to push exposure levels below those caps whenever feasible.

The proposed rule also adds a new provision allowing companies to request a “planned occupational dose limit extension,” permitting a worker to receive up to 10 rem in a single year, twice the current annual limit, as long as total exposure does not exceed 25 rem over five years. NRC officials have said at a public meeting this month that the extension is intended for limited use during tasks such as reactor refueling and equipment upgrades.

NRC Chairman Ho Nieh has defended the change as a matter of regulatory clarity, comparing the ALARA standard to an undefined speed limit: “What does that mean? 50, 45, 25 miles per hour?” Emily Caffrey, a radiation health physicist at the University of Alabama at Birmingham, has also argued the existing standard is ambiguous, telling reporters, “Keeping doses as low as reasonably achievable was a fair idea,” while favoring firmer numerical limits instead.

Edwin Lyman, director of nuclear power safety at the Union of Concerned Scientists, opposes the change. “Removing it would remove that incentive for these companies to continue to maintain the practices that protected their workers and the public,” Lyman said. David Brenner, of Columbia University’s Center for Radiological Research, has noted separately that scientists still face significant difficulty precisely measuring cancer risk from low-dose radiation exposure, a gap the ALARA standard was designed to address by erring toward caution.

The rule change comes as the Trump administration pushes to expand nuclear power generation, in part to meet rising electricity demand from artificial intelligence data centers. Roughly 40 percent of the U.S. population develops cancer at some point during their lifetime, according to figures cited in coverage of the rule change, a baseline researchers use when assessing incremental radiation-related cancer risk under the NRC’s linear no-threshold model.

The proposal does not change the underlying regulatory model the NRC uses to evaluate radiation risk, known as the linear no-threshold model, which assumes that any dose of radiation, however small, carries some corresponding increase in cancer risk. The Union of Concerned Scientists has said that leaving the numerical caps as the sole backstop, without ALARA’s separate requirement to keep pushing exposure lower where feasible, removes a layer of protection the model itself was built to work alongside.

The NRC’s public comment period on the proposed rule remains open through August 31.