Up & Atom


The Nuclear Regulatory Commission (NRC) and its Advisory Committee on Reactor Safeguards (ACRS) have been busy in recent weeks assessing issues related to the licensing of non-light water reactors (non-LWRs).

First, the NRC’s Division of Advanced Reactors transmitted a draft white paper titled “Non-Light Water Review Strategy” on September 30, 2019. As the title suggests, the white paper will “support the [NRC’s] review of applications for non-LWR designs submitted prior to the development of the technology-inclusive, risk-informed and performance-based regulatory framework . . . in 2027.” In so doing, the white paper describes both the contents of such applications and “an approach NRC staff may use to review the license basis information.”

The white paper addresses the following topics:

  • Various approaches to developing the licensing basis for non-LWR designs
  • Background and references for pre-application interactions, contents of applications, and development of safety evaluation reports
  • The scope and focus of the Staff’s technical review
  • The acceptance criteria that could be considered by the Staff during the technical review of a non-LWR application
  • The analysis and evaluation of the integrated system design and expectations for probabilistic risk assessments for non-LWRs
  • Expectations for the applicability of current LWR regulations

The NRC Staff expects the draft white paper “will be finalized by November 2019 to aid in the reviews of non-LWR applications, which may be submitted as soon as December 2019.”

Second, and as documented in its October 7, 2019 letter to Chairman Kristine Svinicki, the ACRS reviewed and assessed a draft SECY paper titled “Population-Related Siting Considerations for Advanced Reactors.” The draft SECY is based on the NRC’s Staff’s June 2019 draft white paper, which assessed potential revisions to Regulatory Guide (RG) 4.7 in the context of advanced reactors. The existing siting guidance in RG 4.7 could unnecessarily limit the locations where advanced reactors could be placed, because RG 4.7 currently recommends that a reactor should be located only in areas where the population density (averaged over any radial distance out to 20 miles) does not exceed 500 persons per square mile.

Of the options presented in the SECY paper, the ACRS concluded that revising the population-related guidance in RG 4.7 to include additional provisions for advanced reactor designs was the most attractive and reasonable. The criteria to be developed would be directly related to estimates of radiological consequences from design-specific events. The ACRS also concluded that this option “retains established principles, while allowing consideration of new reactor characteristics [and that] [a]pplication of [this option] will require substantial effort in identifying licensing basis events for evaluation and in developing mechanistic source terms to support dose calculations.”

Finally, the NRC Staff hosted a public meeting with industry groups and other stakeholders on October 10, 2019 to discuss potential regulatory process improvements related to the licensing of advanced reactors. During that meeting, NRC Staff noted the following:

  • Although the proposed 10 CFR Part 53 (Risk-Informed, Technology Inclusive Regulatory Framework for Advanced Reactors Rulemaking) will address both the licensing and regulation of advanced reactors, other Parts of the 10 CFR will continue to apply to those reactors
  • Part 53 will lay out fundamental safety requirements using the same language and concepts as draft Regulatory Guide 1353 and NEI 18-04, Risk-Informed Performance-Based Guidance for Non-Light Water Reactor Licensing Basis Development
  • Part 53 will include required analyses and acceptance criteria for safety-related structures, systems, and components
  • The Staff does not plan to implement a new licensing process; applicants will continue to apply for either a construction permit and operating license (i.e., the Part 50 framework) or a combined operating license (i.e., the Part 52 framework)
  • The Staff plans to tailor its reviews to focus on the most risk significant items

We will continue to monitor the NRC’s activities regarding the licensing and regulation of advanced reactors.