Radiation Protection Needs a Stopping Point

The Nuclear Regulatory Commission (NRC) is undertaking one of the most significant revisions of its radiation protection framework in decades. As part of its broader implementation of Executive Order 14300, the NRC has proposed replacing the longstanding “as low as reasonably achievable” (ALARA) standard with a graded approach that ties radiation protection requirements more directly to determinate dose thresholds. The proposal responds to the executive order’s direction to reconsider both ALARA and the linear no-threshold model, and shapes how radiation risk is regulated across a wide range of NRC activities. 

BTI supports the NRC’s move toward a more risk-informed framework, but the proposed rule does not resolve the central problem with ALARA: the absence of a clear stopping point for further dose reduction. The proposed thresholds provide greater predictability about when certain radiation protection requirements apply, but many primarily trigger instruction, monitoring, reporting, or other administrative measures. BTI recommends that the NRC give the new framework a clearer organizing structure by codifying the three principles of radiological protection (justification, optimization, and limitation) and specifying how the graded approach implements them. 

Most importantly, BTI recommends establishing a de minimis dose criterion: a point below which residual risk is sufficiently small that additional dose-reduction requirements are no longer warranted. That is different from claiming that radiation below a particular dose has no biological effect. The scientific evidence becomes increasingly unable to resolve effects as doses decline, and BTI argues that the NRC should not make proof of a biological threshold a prerequisite for setting a regulatory boundary. Instead, the NRC should make an explicit regulatory judgment about when additional control is no longer justified. 

BTI recommends 1 mSv (100 mrem) per source per year as the preferred long-term de minimis level, but recognizes that adopting it would require broader changes to the existing public-dose framework and coordination with other federal agencies. If the NRC is not prepared to make those changes in this rulemaking, BTI recommends 0.1 mSv (10 mrem) per source as the strongest immediate option within the existing federal framework, or establishing the 0.25 mSv (25 mrem) cost limitation currently in the proposal as a full de minimis threshold. The criterion would only end the obligation to pursue further dose reduction; monitoring, reporting, recordkeeping, security, safeguards, and other independent requirements would remain in place. These doses are trivial compared to the larger background doses that every human is exposed to each year, and provide regulatory flexibility without improper risk.

The comment also addresses several further flexibilities proposed by the NRC across various applications: caregiver doses, radiopharmaceutical treatment, and veterinary applications.

The NRC cannot complete this reform alone. The EPA previously withdrew separate radionuclide emission standards for NRC-licensed facilities after determining under Clean Air Act Section 112(d)(9) that the NRC’s regulatory program provided an ample margin of safety. That determination relied in part on features of the NRC framework that this rule would change, including ALARA terminology, reactor effluent controls, and the numerical envelope the EPA had evaluated. BTI therefore recommends substantive joint work between the NRC and EPA to establish a renewed and more durable basis for that determination, grounded in the concrete requirements of the revised framework rather than continued reliance on ALARA terminology. 

With a floor, a clear purpose, and a real interagency path, the graded approach could deliver the reform necessary to ground radiation protection standards in actual risk and performance of nuclear technologies.