A cross-disciplinary team from the University of Illinois Urbana-Champaign has submitted a public comment to the U.S. Department of Energy (DOE) raising concerns about a proposed rule that could reduce environmental oversight for advanced nuclear reactors. The full public comment is available here.
Led jointly by Professor Zahra Mohaghegh (Nuclear, Plasma, and Radiological Engineering) and Professor Arden Rowell (College of Law), the team evaluated DOE’s proposed categorical exclusion under the National Environmental Policy Act (NEPA). This rule would allow certain advanced reactor activities—including siting, construction, operation, and decommissioning—to proceed without standard environmental reviews. Other contributors include Ph.D. student George Joslin, Dr. Justin Valentino, and Dr. Seyed Reihani, affiliates of Mohaghegh’s Socio-Technical Risk Analysis (SoTeRiA) Research Laboratory.
Key Concerns
The researchers highlighted three main issues:
- Diversity of Reactor Technologies: NEPA’s categorical exclusions apply to “categories” of actions that are similar to one another and normally lack significant environmental impact. DOE is proposing to treat all advanced reactors as a single category, but these technologies vary widely. Advanced reactors include microreactors, small modular reactors, Generation III+, and Generation IV systems, each differing in core sizes, fuels, coolants, safety systems, and environmental impacts. Moreover, many designs are still in developmental or early deployment with limited operational experience. Because NEPA’s categorical exclusion framework requires a sufficient evidentiary basis to conclude that a defined category normally lacks significant environmental effects, the team notes that DOE cannot reasonably treat such heterogeneous technologies as a single categorical exclusion without oversimplifying technological meaningful distinctions and foreseeable environmental impacts.
- Cumulative Impacts: DOE’s analyses rely on prior single-unit, single-site projects, but multiple reactors at one site or across sites could increase water use, thermal discharges, emergency planning demands, and infrastructure strain—effects not fully addressed in the current record.
- Regulatory Transparency and Predictability: DOE’s proposed “trigger provision”—applying the exclusion only after determining that a project’s attributes sufficiently reduce the risk of adverse offsite consequences from radioactive or hazardous materials—creates uncertainty for stakeholders. Without clearly defined criteria, stakeholders may struggle to predict whether a project qualifies for the exclusion or requires an Environmental Assessment (EA) or Environmental Impact Statement (EIS). The proposed process focuses primarily on radiological considerations and does not explicitly address other environmental impacts such as water use, thermal discharges, or increased human activity.
Implications for Regulation
The proposed categorical exclusion raises concerns regarding DOE’s NEPA compliance and the consistency of applying environmental review procedures within DOE-managed projects. The team also notes potential broader regulatory implications if adopted by other agencies. In particular, the U.S. Nuclear Regulatory Commission—which licenses commercial advanced reactors—should not adopt DOE’s characterization of advanced reactors as technologies that normally have no significant environmental impacts.
About the Project
These comments were developed as part of a research project, funded by a 2024–2027 NRC Research Grant titled “Context-Based Analysis of a Risk-Informed, Performance-Based Regulatory Approach for Advanced Nuclear Reactors” (Grant No. 31310024M0018). The views expressed herein represent the collective professional judgment of the research team and do not necessarily reflect the views of the University of Illinois or the NRC as a funding agency.