ML24158A042
| ML24158A042 | |
| Person / Time | |
|---|---|
| Issue date: | 08/21/2024 |
| From: | Sheila Ray NRC/NRR/DEX/EEEB |
| To: | |
| References | |
| RG-1.238, Rev 0 DG-1354 | |
| Download: ML24158A042 (3) | |
Text
REGULATORY ANALYSIS DRAFT REGULATORY GUIDE DG-1354 CRITERIA FOR THE PROTECTION OF CLASS 1E POWER SYSTEMS AND EQUIPMENT FOR NUCLEAR POWER PLANTS (Proposed new Regulatory Guide 1.238)
- 1.
Statement of the Problem The U.S. Nuclear Regulatory Commission (NRC) is considering issuing a new regulatory guide (RG) on the protection of Class 1E power systems and equipment at nuclear power plants as Draft Regulatory Guide (DG-1354). This proposed RG incorporates the NRCs implementation of a risk-informed, performance-based approach to licensing. This guide will endorse, with clarifications and exceptions, the Institute of Electrical and Electronics Engineers (IEEE) Standard (Std.) 741-2022, IEEE Standard for Criteria for the Protection of Class 1E Power Systems and Equipment for Nuclear Power Generating Stations. IEEE Std. 741-2022 provides design criteria, design features, and testing provisions for the protection of safety-related or Class 1E power systems and equipment supplied from those systems at nuclear power plants. The new guide will apply to nuclear power plants licensed under Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Domestic Licensing of Production and Utilization Facilities, or 10 CFR Part 52, Licenses, Certifications, and Approvals for Nuclear Power Plants, which include operating reactors, new reactors, small modular reactors, and advanced reactors.
The NRC has published several documents addressing offsite power, degraded voltage relay considerations, and the protection of Class 1E power systems, including the following:
Information Notice 1995-05, Undervoltage Protection Relay Settings Out of Tolerance Due to Test Equipment Harmonics, dated January 20, 1995 (Agencywide Documents Access and Management System Accession No. ML031060397)
Regulatory Issue Summary 2011-12, Adequacy of Station Electric Distribution System Voltages, dated December 29, 2011 (ML113050583)
Information Notice 2012-03, Design Vulnerability in Electric Power System, dated March 1, 2012 (ML120480170)
Bulletin 2012-01, Design Vulnerability in Electric Power System, dated July 27, 2012 (ML12074A115), and its closure (88 FRN 13855)
The new guide will take into consideration all of the above operating experience and lessons learned.
- 2.
Objective The objective of this regulatory action is to assess the need to update NRC guidance and provide applicants with a method to demonstrate compliance with the requirements given in
Page 2 10 CFR Part 50, Appendices A and B, and 10 CFR Part 52 for the protection of Class 1E power systems and equipment.
- 3.
Alternative Approaches The NRC staff considered the following alternative approaches:
(1)
Do not issue RG 1.238.
(2)
Issue RG 1.238.
Alternative 1: Do Not Issue RG 1.238 Under this alternative, the NRC would not issue additional guidance, and the current guidance would be retained. If the NRC does not take action, there will be no changes in costs or benefits to the public, licensees, or the NRC. This alternative is considered the no-action alternative and provides a baseline condition from which any other alternatives will be assessed.
The no-action alternative would not address the absence of NRC guidance on this topic. The NRC would continue to review each application on a case-by-case basis.
Alternative 2: Issue RG 1.238 Under this alternative, the NRC would issue RG 1.238, Criteria for the Protection of Class IE Power Systems and Equipment for Nuclear Power Plants, which would provide the latest information on the protection of Class 1E power systems and equipment, supporting guidance, and review practices. By issuing this RG, the NRC would ensure that the guidance available in this area is current and accurately reflects the staffs position.
The impact to the NRC would consist of the costs associated with preparing and issuing the RG. The impact to the public would consist of the voluntary costs associated with reviewing the draft guide and providing comments to the NRC during the public comment period. The value to the NRC staff and license applicants would lie in the enhanced efficiency and effectiveness provided by the use of a common guidance document as the technical basis for license applications and for other interactions between the NRC and the entities it regulates.
- 4.
Comparison of Alternatives The alternatives were compared against each other with respect to safety, as well as NRCs and applicant/licensees resources.
With respect to safety, Alternative 1 does not signify unsafe results since applicants and licensees would adopt methods that would be evaluated by NRC staff on a case-specific basis to establish its reasonable assurance of safety finding. However, Alternative 2 would be superior to Alternative 1 in that it would issue a new RG to include implementation of a risk-informed, performance-based approach and include updated codes/standards to maintain and or potentially enhance safety, improve clarity, and increase uniformity in review of applications and license amendments, etc.
With respect to NRC resources, Alternative 2 represents the greatest initial cost to the NRC, which is attributable to the costs associated with preparing and issuing the RG revision.
However, over the lifetime of the RG, the total NRC cost of Alternative 2 is estimated to be less than the overall cost of Alternative 1 by reducing the cost related to additional staff resources
Page 3 and schedule impacts associated with the staff reviews and request for information (RAI) procedures.
With respect to applicants/licensees resources, Alternative 2 results in the least costs when compared to Alternative 1. Having a new RG should reduce the need for RAIs and therefore the need for applicants and licensees to perform additional analyses to address them. Accordingly, costs to applicants and licensees associated with these additional activities are estimated to be lower with Alternative 2.
- 5.
Conclusion Based on this regulatory analysis, the NRC staff concludes that the issuance of a new RG is warranted. The action will enhance safety and provide guidance on the protection of Class 1E power systems and equipment.
Issuing this RG to endorse portions of a consensus standard is consistent with the NRC policy of evaluating the latest versions of national consensus standards to determine their suitability for endorsement by RGs. Such activities also conform to the NRCs Management Directive 6.5, NRC Participation in the Development and Use of Consensus Standards, dated December 20, 2011 (ML100600460), which is in accordance with the National Technology Transfer and Advancement Act of 1995 (Public Law 104-113).