ML23123A095

DG-4034 (RG 4.7 Rev 4) Regulatory Analysis (non-LWRs and Lw Smrs)

ML23123A095
Person / Time
Issue date:	10/12/2023
From:	Sosa B NRC/NRR/DANU/UARP
To:
Shared Package
ML23123A081	List: ML23123A090 ML23123A095 ML23135A003
References
RG 4.7 Rev 4 DG-4034
Download: ML23123A095 (3)

Text

REGULATORY ANALYSIS

DRAFT REGULATORY GUIDE DG-4034 GENERAL SITE SUITABILITY CRITERIA FOR NUCLEAR POWER STATIONS (Proposed Revision 4 of Regulatory Guide 4.7)

1. Introduction

This document analyzes the determination by the U.S. Nuclear Re gulatory Commission (NRC) regarding whether it should expend resources to revise Re gulatory Guide (RG) 4.7, General Site Suitability Criteria for Nuclear Power Stations. It considers the potential benefits and costs to the NRC and stakeholders. It does not consider the cost of implementation by existing licensees since this guide is for applicants of new co mmercial nuclear power plants.

Furthermore, the cost of implement ation by licensees was covere d by the regulatory analysis done for the rule(s) upon which the guide is based.

2. Statement of the Problem

The NRC published Revision 3 of RG 4.7 in March 2014; it descri bes a method the NRC considers acceptable to implement the site suitability requirem ents for nuclear power stations.

The current version of RG 4.7 (Revision 3) does not reflect the NRCs implementation of a risk-informed, performance-based approach to licensing.

Since the issuance of Revision 3 of RG 4.7, alternative approac hes to the populationdensity criterion have been developed for non-light-water-react or (non-LWR) technology and light-water small modular reactors (SMRs). The N RC staff is considering revising RG 4.7 to support licensing for non-LWR technology and light-water SMRs by providing alternatives to the population-density criterion based on estim ates of radiological consequences from design-specific events and to provide additional methods t hat applicants can use to meet the siting requirements of Title 10 of the Code of Federal Regulations (10 CFR) 100.21(h) to ensure consistency in new reactor licensing reviews and promote a more effective and efficient licensing process.

The NRC staff interacted with stakeholders to develop several o ptions for the Commissions consideration to address population-related siting questions for advanced reactors. The options developed, along with their advantages an d disadvantages are detailed in SECY-20-0045 Population-related Siting Considerations for Adva nced Reactors (ADAMS Accession No. ML19143A194). The NRC Commissioners provided thei r selected option and associated direction to the staff in a Staff Requirements Memor andum (SRM) to SECY-20-0045 (ADAMS Accession No. ML22194A885).

3. Objective

The objective of this regulatory action is to assess the need t o update the NRC guidance and provide applicants with alternatives to demonstrate complia nce with 10 CFR100.21(h) in determining the suitability of siting commercial non-LWRs and l ight-water SMRs closer to population centers than has typically been permitted for large LWRs.

4. Identification and Analysis of Alternative Approaches

The NRC staff considered the following alternative approaches:

(1) Do not revise Regulatory Guide 4.7 and maintain the status quo with no changes to the existing guidance in RG 4.7.

(2) Withdraw Regulatory Guide 4.7.

(3) Revise Regulatory Guide 4.7 to provide siting density guida nce for siting of non-LWR technology and light-water SMRs.

Alternative 1: Do Not Revise Regulatory Guide 4.7

Under this alternative, the NRC would not revise or issue addi tional guidance, and the current guidance would be retained. If the NRC does not take action, there would be no changes in costs or benefits to t he public or the NRC. This alternative is considered the no-action alternative and provides a baseline condition from whic h any other alternatives will be assessed. However, the no-acti on alternative would not support licensing for non-LWRs and light-water SMRs.

Alternative 2: Withdraw Regulatory Guide 4.7

Under this alternative, the NRC would withdraw RG 4.7. This wo uld eliminate the only readily available guidance to assist applicants in the initial stage of selecting potential sites for a nuclear power station. Although this alternative would be less costly than revising the guide to address identified issues, it would leave stakeholders without guidance to address given regulatory requirements.

Alternative 3: Revise Regulatory Guide 4.7

Under this alternative, the NRC would revise RG 4.7. This revis ion would address the problems identified above regarding the use of alternative popu lation-density criteria for the siting analysis of non-LWRs and light-water SMRs. By doing so, the NRC would ensure that the guidance available in this area is current and accurately refle cts the staffs position.

The impact on the NRC would be the costs associated with preparing and issuing the RG revision. The impact on the stakeholders would be the volunt ary costs associated with reviewing and providing comments to the NRC during the public c omment period. The value to the NRC staff and its applicants would be the benefits associat ed with enhanced efficiency and effectiveness in using a common guidance document as the techni cal basis for license applications and other interactions between the NRC and its reg ulated entities.

5. Comparison of Alternatives

The NRC compared the alternatives against each other with respe ct to safety and the NRCs and applicants resources.

With respect to safety, Alternatives 1 and 2 do not signify uns afe results since applicants would adopt methods that would be evaluated by NRC staff on a c ase-specific basis to establish a finding of reasonable assurance of adequate protection of the public health and safety.

Page 2 Alternative 3 would be superior to Alternatives 1 and 2 in that the NRC would issue a revised siting RG to include alternative approaches to address populati on-related siting considerations thereby maintaining and potentially enhancing safety, improving clarity, and increasing uniformity in application reviews.

With respect to NRC resources, Alternative 3 represents the gre atest initial cost to the NRC, which is attributable to the costs associated with prepari ng and issuing the RG. However, over the lifetime of the RG, the NRC staff estimates that the o verall NRC cost of Alternative 3 is less than the overall cost of Alternative 1 due to the reductio n in staff resources and schedule impacts associated with application reviews and requests for ad ditional information (RAI) procedures. Alternative 2 is pot entially the most expensive alternative for the NRC and applicants because, in the absence of NRC guidance, applicants would lack methods that the NRC staff has already approved for meeting a given set of regul ations. In this case, applicants would need to develop their own methods for alternative approac hes to address population-related siting considerations and demonstrate their effectivene ss to the NRC. The NRC staff would be burdened by reviewing alternative methods, and this ma y result in issuing multiple RAIs to applicants that would in turn increase the review burde n on staff and might impact schedules.

With respect to applicants resources, Alternative 3 results in the least cost when compared to Alternatives 1 and 2. Having a revised RG should reduce the nee d for RAIs and therefore the need for applicants to perform additional analyses to address t hem. Accordingly, costs to applicants associated with these additional activities are esti mated to be lower with Alternative 3 than Alternative 1. Alternative 2 would be the most expensive a lternative because eliminating the RG would require applicants to develop their own methods fo r damping criteria and demonstrate their effectiveness to the NRC, thereby increasing costs for applicants.

6. Decision Rationale

Based on this regulatory analysis, the NRC staff concludes that a revision of RG 4.7 is warranted. The action will address the problems identified abov e regarding the use of alternative population-density criteria for the siting analysis of non-LWRs and light-water SMRs.

It could also lead to cost savings for the industry, especially with regard to an applicants ability to prepare submittals to the NRC. An updated guide would potent ially reduce staff review time and the need for RAIs, thus reducing costs to applicants and th e NRC. The costs to the NRC in revising the RG and applicants in adapting to a revised RG are deemed to be less than the benefits accrued by reducing the need for RAIs. The results of this analysis is consistent with SRM to SECY-20-0045 in which the Commission selected Option 3, to revise the guidance in RG 4.7 that relates to 10 CFR 100.21(h) to include provisions f or advanced reactor designs.

Page 3