On Friday, February 3, the U.S. Nuclear Regulatory Commission (NRC) published in the Federal Register draft “Guidance for Developing Principal Design Criteria for Non-Light Water Reactors.”  This draft new regulatory guide (identified as DG-1330) helps explain how the NRC’s “general design criteria” for traditional light-water nuclear power plants could be applied to non-light water (a.k.a. “advanced”) nuclear reactor design submissions, enabling applicants to develop principal design criteria as part of their regulatory filings.  Comments are due on the guidance by April 4, 2017.

The draft regulatory guide is a significant publication of over a 100 pages.  It provides a background of the NRC’s policy on advanced nuclear reactors, the role of general design criteria in reactor licensing, and joint NRC-U.S. Department of Energy (DOE) efforts to tailor the agency’s general design criteria to advanced reactors.  The general design criteria for traditional nuclear power plants are found at Appendix A to 10 C.F.R. Part 50, the chapter of the Code of Federal Regulations that contains the NRC’s primary regulations on nuclear power plant design.

But most interesting are the three appendices, which propose (A) technology-neutral design criteria for advanced reactors generally, (B) technology-specific design criteria for sodium-cooled fast reactors (SFRs), and (C) technology-specific design criteria for modular high temperature gas-cooled reactors (mHTGRs).  The appendices contain not only the design criteria, but the “NRC Rationale” explaining why/how they were adapted from the general design criteria.  In addition, pages 13 to 20 of the draft guide compare the three design criteria to the current set tailored to light-water reactors.

This is an important document that deserves close attention by the advanced reactor community.  It provides one of the first detailed insights into how the NRC views advanced reactors, how far it is willing to step away from the general design criteria framework, and what it finds of importance from a safety perspective for advanced reactors.

Notably, the basic approach taken by the NRC appears to mimic what the DOE suggested in its 2014 report, “Guidance for Developing Principal Design Criteria for Advanced (Non-Light Water) Reactors.”  There, the DOE likewise “proposed a set of advanced reactor design criteria” to serve in lieu of the general design criteria, but also proposed separate design criteria for SFRs and mHTGRs.  As explained by the NRC here, the DOE’s rationale was “that the safety objectives for some of the current [general design criteria] did not address design features specific to SFR and mHTGR technologies (e.g., sodium or helium coolant, passive heat removal systems, etc.).  Additional design criteria were developed to address unique features of those designs.”

It should be mentioned that this guide is just that—guidance.  As made clear in the draft guide, the proposed design criteria “are intended to provide stakeholders with insight into the staff’s views on how the [general design criteria] could be interpreted to address non-LWR design features,” but they are not binding.  It is still on the applicant to develop principal design criteria for her application, “considering public safety matters and fundamental concepts, such as defense in depth, in the design of their specific facility and for identifying and satisfying necessary safety requirements.”

Moreover, the regulatory framework for advanced reactors is still in flux.  As noted in a prior blog entry, this January legislation was introduced in Congress “to spur technology development related to advanced reactors.”  Recently, on January 23, separate legislation “to provide regulatory certainty for the development of advanced nuclear energy technologies” passed the House of Representatives.  This latter bill, entitled the “Advanced Nuclear Technology Development Act of 2017” is related to a prior bill that passed the House of Representatives in 2016, and was examined by our team here.

The advanced reactor industry is certainly picking up steam.  Terrestrial Energy earlier this month informed the NRC that it plans to file a license application for its molten salt reactor in 2019.  LeadCold around the same time announced a $200 million deal to develop its lead-cooled reactor.  We hope the NRC’s actions here evidence continued support for the advanced reactor community, and a willingness to recognize the unique safety and security benefits these new designs bring.

Please feel free to contact the authors with any questions.