ML25076A690

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Ee ACRS Presentation
ML25076A690
Person / Time
Issue date: 03/17/2025
From: Wendell Morton, Liliana Ramadan, Sheila Ray
NRC/NRR/DEX/EEEB
To:
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Download: ML25076A690 (1)
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ACRS: Electrical Engineering Briefing March 20, 2025 Wendell Morton Liliana Ramadan Sheila Ray

Opening Remarks Wendell Morton

Acronyms BL - Bulletin BTP - Branch Technical Position CFR - Code of Federal Regulations DG - Draft Guide EDG - Emergency Diesel Generator EE - Electrical Engineering EQ - Environmental Qualification FERC - Federal Energy Regulatory Commission GDC - General Design Criteria IAEA - International Atomic Energy Agency IEC - International Electrotechnical Commission IEEE - Institute of Electrical and Electronics Engineers NEA - Nuclear Energy Agency NERC - North American Electric Reliability Corporation PRA - Probabilistic Risk Assessment RG - Regulatory Guide SRP - Standard Review Plan Std - Standard TSTF - Technical Specification Task Force 3

Agenda Opening Remarks Overview of Electrical Engineering (EE) & Environmental Qualification (EQ) regulations Licensing EE & EQ activities in operating reactors, new and advanced reactors, small modular reactors, license renewal, & research projects Open Phase Regional Coordination Infrastructure

  • Vision & Strategy for EE Regulatory Guides (RGs) & Upcoming RG work
  • DG-1427 public comment resolution/status

Agenda, cont.

Infrastructure, cont.

  • Risk-informed graded approach - NuScale review
  • Technical Specification Task Force (TSTF) 505 license amendment requests
  • DG-1438 questions
  • Standard Review Plan Status

Staff & Contributors Electrical Engineering Branch (NRR/DEX/EEEB)

Overview of Pertinent Regulations Electrical Engineering 10 CFR 50, Appendix A, General Design Criteria (GDC)

  • GDC 17, Electric Power Systems
  • GDC 18, Inspection and Testing of Electric Power Systems Environmental Qualification 10 CFR 50, Appendix A, GDC 4, Environmental and Dynamic Effects Design Bases 10 CFR 50.49, Environmental qualification of electric equipment important to safety for nuclear power plants License Renewal 10 CFR Part 54, Requirements for Renewal of Operating Licenses for Nuclear Power Plants 7

REGULATIONS 10 CFR Part 50:

50.34, 50.49, 50.55(a)(h), 50.63, 50.65, 50.69, 50.71, GDC 2, GDC 4, GDC 5, GDC 17, GDC 18, GDC 50, App. B 10 CFR Part 52 (New Reactors)

Proposed 10 CFR Part 53 (Advanced Reactors) 10 CFR Part 54 (License Renewal)

Licensing: Operating Reactors

  • Operating Reactors
  • Regional Coordination EE Counterpart Meeting with NRR, RES, Regions for technical discussions and dialogue Inspection support 8

Licensing: Open Phase Condition What is an open phase condition (OPC)?

  • OPC is defined as the open circuit of one or two of the three phases of any offsite power circuit required for normal operation of electrical systems.

What are the consequences?

  • The 2012 operating event at Byron Station (ML12272A358) revealed a significant design vulnerability issue
  • OPC in the plants offsite power supply will cause a common cause failure of AC electric power system
  • Loss of safety functions of Engineered Safety Features
  • Both offsite and onsite electric power systems were not able to perform their intended safety functions due to the design vulnerability 9

Licensing: Open Phase Condition Past operating experience involved offsite power supply circuits that were rendered inoperable by an open-circuited phase, and the condition went undetected for several weeks because offsite power was not aligned during normal operation and the surveillance procedures, which recorded phase-to-phase voltage, did not identify the loss of the single phase.

How was OPC addressed?

  • Risk-informed option - perform a risk evaluation under certain boundary conditions to support an alarm and manual response to an OPC 10

Licensing: Open Phase Condition NRC Actions Following the Byron event

  • July 2012 - Issued Bulletin 2012-01: Design Vulnerability in Electric Power System
  • February 2013 - Summary Report - Documented the review of licensee responses and staff recommendations
  • July 2015 - BTP 8-9 (Rev. 0) issued after resolution of public comments and review by ACRS
  • March 2017 - SRM-SECY-16-0068 directed staff to verify licensees implementation and update the Reactor Oversight Process to provide periodic oversight of industrys implementation of OPC initiative

11

Licensing: Open Phase Condition

  • NRC Actions Following the Byron event, cont.
  • August 2020 - Issued Revision 2 of the TI 2515/194, Inspection of the Licensees Implementation of Industry Initiatives Associated with the Open Phase Condition Design Vulnerabilities in Electric Power Systems to verify that licensees have appropriately implemented the voluntary industry initiative
  • March 2023 - Completion of issuance of closure letters to licensees and Bulletin 2012-01 closure
  • Current activities - Revision of BTP 8-9 (will be upcoming Revision 1) 12

Licensing: Advanced and Small Modular Reactors

  • Advanced Reactors
  • Terrapower Construction Permit Application
  • Small Modular Reactors
  • NuScale US460 Standard Design Approval 13

Licensing: Decommissioning &

Nuclear Facilities

  • Decommissioning
  • Peach Bottom Unit 1
  • Request for Alternative Schedule to complete decommissioning activities
  • Nonpower Production and Utilization Facilities 14

Licensing: License Renewal Initial License Renewal Clinton Comanche Peak Diablo Canyon Perry Subsequent License Renewal Browns Ferry Dresden Monticello North Anna Oconee Peach Bottom Point Beach Surry St. Lucie Turkey Point VC Summer 15

Licensing: Research

  • Research Projects
  • Valve-Regulated Lead-Acid battery technology
  • Islanding
  • Assessment of research efforts after the issuance of Expanded Materials Degradation Assessment (EMDA): Aging of Cables andCable Systems (NUREG/CR-7153, Volume 5)
  • Future Focused Research on novel and innovative cable condition monitoring techniques 16

Licensing: Environmental Qualification (EQ)

  • Licensing of new reactors, advanced reactors and small modular reactors

Potential impacts to EQ design inputs such as radiological dose, pressure, temperature, etc.

17

Infrastructure: IEEE participation NRC staff provide technical expertise and offer technical insights to present agency positions for potential inclusion in standards and development of high-quality standards Under the IEEE Power and Energy Society, NRC staff participate in:

  • Nuclear Power Engineering Committee
  • Energy Storage and Stationary Battery Committee
  • Power System Relaying and Control Committee
  • Power System Communications and Cybersecurity Committee
  • Insulated Conductors Committee
  • Transformers Committee 18

Infrastructure: Vision & Strategy of EE Regulatory Guidance Inline with ADVANCE Act, Leverage Action Plan for Enhancing NRCs Codes and Standards Program for Future Reactors Focus on the agency mission and regulatory requirements when determining if an RG is needed or requires updating Represent a technically acceptable approach for allowing licensees, manufacturers, vendors, and NRC staff to effectively navigate and use regulatory guidance Prevent the ad hoc approach of generating additional regulatory guidance documents Gather and analyze operating experience Applicable to licensees and applicants subject to 10 CFR Parts 50 & 52 19

Infrastructure: Vision & Strategy of EE Regulatory Guidance Ensuring new RGs or revisions of RGs are aligned Commission PRA Policy and providing risk informed and performance-based methods Combine related standards on a technical topic into one RG Reduced staff hours as compared to updating and maintaining several RGs Reduced costs as compared to updating and maintaining several RGs Technical Efficacy - Generates efficiencies such that industry/users have a one-stop shop on NRC positions on a particular topic Process Efficiency - review process is streamlined for one RG on a technical topic (i.e., one public comment period on a technical topic)

Updates to a combined RG endorsing several standards would only be considered when there are significant changes that impact the staffs position or provide additional clarifications 20

Infrastructure: EE RG Checklist

  • The EE RG Checklist was developed to improve and increase process efficiency
  • Regulatory Guide and Programs Management Branch (RES/DE/RGPMB) owns the RG process
  • EE staff are the technical leads for EE RGs
  • EE RG Checklist provides an overview of the process and outlines actions to prepare a DG and publish the final RG
  • Incorporates insights from staff and management, share the lessons learned to help improve the development process 21

Infrastructure: DG-1427

  • DG-1427, Qualification of Fiber-Optic Cables, Connections, and Optical Fiber Splices for Use in Safety Systems for Production and Utilization Facilities. ML24201A068
  • Issued Oct 2024 to endorse, with clarifications, IEEE Std. 1682-2023, IEEE Standard for Qualifying Fiber Optic Cables, Connections, and Optical Fiber Splices for Use in Safety Systems in Nuclear Power Generating Stations.
  • Public comments received and staff is addressing them to issue the final RG in Spring 2025.

22

Infrastructure: DG-1427 ACRS comments in ACRS Planning & Procedures Portion of the October 2024 Full Committee Meeting

  • Related to the qualification for severe accident
  • Added paragraph in Background on 10 CFR 50.155(c)
  • Equipment relied on for the mitigation strategies and guidelines required by 10 CFR 50.155(b)(1) must have sufficient capacity and capability to perform the necessary functions.
  • Type testing could be used to demonstrate the capability of equipment to perform credited functions under extreme natural events or severe accident/design extension conditions.
  • Identification of regulatory positions as exceptions was deleted.

23

Infrastructure: Upcoming RG Work

  • Risk-Informed Categorization of Electrical and Electronic Equipment
  • Staff is considering endorsement of the next revision of IEEE Std. 1819, IEEE Standard for Risk-Informed Categorization and Treatment of Electrical and Electronic Equipment at Nuclear Power Generating Stations and Other Nuclear Facilities in a new RG.
  • The next revision of the standard is expected in 2026
  • NRR/DRA is in the process of revising RG 1.201, Guidelines for Categorizing Structures, Systems, and Components in Nuclear Power Plants According to Their Safety Significance 24

Infrastructure: Upcoming RG Work

  • Valve-Regulated Lead-Acid Batteries
  • New RG to endorse the following standards, with clarifications:
  • IEEE Std. 1187, IEEE Recommended Practice for Installation Design and Installation of Valve-Regulated Lead-Acid Batteries for Stationary Applications
  • IEEE Std. 1188, IEEE Recommended Practice for Maintenance, Testing, and Replacement of Valve-Regulated Lead-Acid Batteries for Stationary Applications
  • Expect to complete draft by end of 2025 25

Infrastructure: Upcoming RG Work

  • Qualification of Vented Lead-Acid Batteries
  • Revision of RG 1.158 Qualification of Safety-Related Lead Storage Batteries for Nuclear Power Plants
  • To endorse, with clarifications, IEEE Std. 535-2022, IEEE Standard for Qualification of Class 1E Vented Lead Acid Storage Batteries for Nuclear Power Generating Stations
  • Expect to complete draft by Summer 2025 26

Infrastructure: Upcoming RG Work

IEC/IEEE 63332-387:2024, Nuclear facilities --

Electrical power systems -- Diesel generator units applied as standby power sources IEEE Std. 2420-2019, IEEE Standard Criteria for Combustion Turbine-Generator Units Applied as Standby Power Supplies for Nuclear Power Generating Stations Expect to complete draft by Fall 2025 27

Infrastructure: Commission PRA Policy Alignment

  • NuScale
  • Risk-informed graded approach to evaluate the DC systems
  • Open Phase, as previously discussed
  • Risk-Informed Option
  • Revision of BTP 8-9 28

Infrastructure: Commission PRA Policy Alignment License Amendment Requests

  • TSTF-439, Eliminate Second Completion Times Limiting Time From Discovery of Failure to Meet an LCO ML051860296
  • 10 CFR 50.69, Risk-informed categorization and treatment of structures, systems and components for nuclear power reactors
  • Technical Specification completion time extension 29

Infrastructure: Continued Alignment with the Commission PRA Policy

  • DG-1438, Periodic Testing of Electric Power and Protection Systems (Proposed Revision 4 to RG 1.118)
  • ACRS comments noting the paragraph on 10 CFR 50.155
  • Expect publication of DG-1438 in Spring 2025 30

Infrastructure: Standard Review Plan Status

Infrastructure: Operating Experience

  • Review electrical operating experience
  • Participate in Technical Review Groups to identify trends
  • Informs EE RG strategy
  • Potential for generic communications
  • Assist in standards development process 32

FERC/NERC Coordination

  • FERC quarterly meetings
  • Restart of information exchange on technical topics of mutual interest
  • Biannual Joint Commission Meetings between FERC and NRC, with NERC participation 33

International Activities

  • International Electrotechnical Commission (IEC)
  • Participate in development of international standards on EDG, battery, grid coordination, condition monitoring of cables, etc.
  • As NPP designers participate in the world market, international standards have been used for design, operation and maintenance in US licensing
  • Provide technical expertise, share operating experience, and offer technical insights to present agency positions for potential inclusion in standards 34

International Activities

  • Nuclear Energy Agency (NEA)
  • Participate in Working Group on Electrical Power Systems.
  • Exchange of information and experience on the safety of electrical systems.
  • Facilitate international convergence on safety issues related to the safety of electrical systems and, where practicable, seek to develop a shared understanding and recommend solutions on important issues.
  • Allow prompt attention to evolving electrical plant events to share the lessons learned.

35

International Activities

  • International Atomic Energy Agency (IAEA)
  • Participate and author sections for the revision to Nuclear Energy Series NG-T-3.8, Electric Grid Reliability and Interface with Nuclear Power Plants to include information on the development, deployment, and oversight of small modular reactors
  • Participate in the update of Safety Report Series No. 82, Revision 2, Ageing Management for Nuclear Power Plants: International Generic Ageing Lessons Learned (IGALL) 36

International Activities

  • Poland
  • The NRC and Polands nuclear regulator, the National Atomic Energy Agency (known as PAA), have a cooperation agreement.
  • The cooperation included an exchange information on Westinghouses AP1000 electrical systems, offsite power, inspections, & EQ in Summer 2024.

37

International Activities

  • Romania
  • Bilateral cooperation for technical exchange &

regulatory information sharing

  • Shared information on EQ and DC systems in Summer 2024
  • Other countries
  • Routinely respond to information requests on EDG, grid, and other technical topics 38

Summary

  • Advance licensing projects on operating reactors, advanced reactors, small modular reactors and production and utilization facilities.

Commission PRA Policy.

  • Initiate new and revised RGs based on up-to-date standards, operating experience, and risk informed and performance-based methods.
  • Coordinate with FERC/NERC on the state of the grid and impact on nuclear.
  • Engage international counterparts to inform NRCs mission objectives.

39

Thank you for your time and attention.

Questions?

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