NRC Drops ALARA, Keeps LNT: What Actually Changes?

What happened?

On 1 July 2026 the US Nuclear Regulatory Commission (NRC) proposed an update to its radiation-protection regulations. The headline part: the NRC proposes to remove the decades-old "as low as reasonably achievable" (ALARA) principle from its rules.¹ The proposal is part of the reform process under Executive Order 14300, signed by President Trump in May 2025.³

But on closer reading the picture is far more measured than the headline suggests. In the words of NRC Chairman Ho K. Nieh: "We're raising the standard for regulatory clarity, not lowering the standard for safety. Our radiation dose limits remain unchanged — what we're eliminating is unnecessary ambiguity."¹

What are LNT and ALARA?

Two abbreviations sit at the centre of the debate:

• LNT (linear no-threshold): the model assuming that the health effect of radiation rises linearly with dose and that no safe threshold dose exists. Its basis is biological: even a single photon can damage DNA, and repair mechanisms are imperfect. At very low doses the effect is hard to demonstrate decisively, but out of caution regulatory frameworks adopt LNT.⁵
• ALARA (as low as reasonably achievable): if LNT holds, every dose carries some risk, so minimizing dose reasonably is the natural consequence of protection. The contested word is "reasonable" — subjective and context-dependent. Our detailed ALARA article and LNT/effect-types article explain these from the ground up.

What the NRC proposes

The key point: the LNT model is not going away. The NRC states that "no consensus-supported, regulation-ready alternative model to LNT exists at this time" and keeps LNT as appropriate for formulating protection standards.⁴ What changes is mainly the term itself: the NRC proposes removing "ALARA" from its regulations and replacing it with a less-subjective, graded, risk-informed approach to dose management.¹

The NRC's rationale is that ALARA's "reasonableness" test has drifted over time — into an expectation that "if a means of dose reduction is available, it should be applied regardless of its reasonableness relative to the total dose and the amount of reduction" — which it argues breeds ambiguity, excessive subjectivity and inconsistent enforcement.²

Other elements of the proposal: more flexibility to use modern methods for dose evaluation; expanded options for managing occupational exposure; and allowing caregivers of patients receiving radioactive-material treatments to voluntarily receive higher doses to improve patient care.¹

Tension with the order

Notably, the NRC keeps LNT despite the executive order. EO 14300 explicitly called LNT and the ALARA standard built on it "flawed" and "irrational" and asked for reconsideration.³ Yet the NRC leaves the logic intact: it maintains that a threshold "could only occur if DNA repair were totally effective in that dose range or if a single radiation track could not produce an effect," which it deems unlikely.⁴ So the term ALARA goes, but the LNT that scientifically underpins it stays.

What it means for medicine and radiology

The most common misreading might be: "If ALARA is gone, is dose optimization in radiology over too?" No. A few boundaries are worth drawing:

• This rule concerns the occupational and public protection rules under the NRC's authority — for nuclear plants, fuel cycle and radioactive-material uses in medicine/research. Diagnostic x-ray/CT equipment in the US is largely regulated by states and the FDA; this proposal is not directly about them.
• The international framework is unchanged. Optimization of protection (the substance of ALARA) is one of ICRP's three core principles and part of the IAEA's international Basic Safety Standards (GSR Part 3).⁵⁶ One US agency's terminology choice in its own rules does not bind other countries' regulations — including Türkiye's — or the practice of optimization in clinical imaging.
• So in clinical radiology the principles of justification and optimization — protecting the patient from unnecessary dose, aiming for the lowest dose needed for diagnosis — remain fully in force. What changes is one country's regulatory language for specific licensees, not the principle.

Support and criticism

The issue divides even the nuclear community. Among supporters: a July 2025 Idaho National Laboratory report argued for eliminating ALARA and setting higher dose limits, contending that the subjectivity of "reasonable" produces an endless ratchet and inconsistent enforcement.⁴ Among critics: the Union of Concerned Scientists calls the proposal a "weakening that puts workers and communities at risk," and some experts (e.g. in Scientific American) argue looser limits will not help nuclear energy. Interestingly, a view from within the sector also holds that the term should be "modernized, not scrapped."⁷

The numbers temper expectations too: press analyses put the estimated industry saving at only about $9.5 million a year; spread across the dozens of US reactors, a modest sum per plant. And any organization already in compliance stays compliant without changes; the shift mainly concerns new reactors and designs.⁴

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