SMRs are defined broadly to include a range of technologies, particularly a range of diverse fuels and coolants. US SMR reactor technology currently chosen for NRC licensing and near-term commercial deployment (2022-2025) is based on LWR technology. Most of these SMRs will be integral pressurized water reactors (iPWRs) as discussed in Part II of this Handbook. LWRs have a well-established framework of regulatory requirements, a technical basis for these requirements, and supporting regulatory guidance that provides acceptable approaches for meeting NRC requirements. The NRC uses a standard review plan (SRP), NUREG-0800, to review licensing applications for these reactor designs. NUREG-0800 was revised in January 2014 to provide general review guidance for SMRs. The NRC will require design-specific SRPs for the licensing of SMRs. These SRPs are under development by the NRC and SMR vendors. The SRP for the B&W mPower design is expected to be published in mid-2014 to support the submittal of the mPower design certification application scheduled in 2015. Additionally, the NRC has a well-established set of validated analytical codes and methods and a well-established infrastructure for conducting safety research needed to support its independent safety review of an LWR plant design and the technical adequacy of a licensing application. It should be emphasized that the near-term SMRs, particularly the iPWRs, will be subject to the same licensing process and the same safety requirements and standards as new large LWRs resulting in no diminution of safety.

New SMRs can be licensed under either of two existing regulatory approaches. The first approach is the traditional ‘two-step’ process described in Title 10, Part 50, ‘Domestic Licensing of Production and Utilization Facilities,’ of the Code of Federal Regulations (10 CFR Part 50), which requires first a construction permit (CP) and then a separate operating license (OL). The second approach is the new ‘one — step’ licensing process described in 10 CFR Part 52, ‘Licenses, Certifications, and Approvals for Nuclear Power Plants,’ which incorporates a combined construction and operating license (COL). It should be noted that the both the SMR vendor B&W and the proposed license applicant TVA have chosen the two-step Part 50 process for licensing of the mPower SMR at the Clinch River, Tennessee site. This two — step process was chosen by TVA and approved by the NRC for this first-of-a-kind (FOAK) design to reduce the risk of delay in obtaining a final design certification under the Part 52 process. It is assumed that all other U. S. applicants for FOAK SMRs and nth of a kind SMRs will adhere to the Part 52 NRC licensing process.

Key to the licensing of any new reactor design, including SMRs, is the approach that the regulatory authority will utilize in assessing the safety basis for the reactor and associated safety systems. Regardless of the licensing process chosen, the licensing authority will need to consider the relative merits of a deterministic versus a risk-informed performance-based approach to assess and approve the safety case for SMRs.