ML26005A084
| ML26005A084 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 01/08/2026 |
| From: | Markley M NRC/NRR/DORL/LPL2-1 |
| To: | Huecker J Duke Energy Carolinas |
| Stone Z | |
| References | |
| EPID L-2025-LLR-0072 | |
| Download: ML26005A084 (0) | |
Text
January 8, 2026 Mr. Jonathan Huecker Site Vice President Catawba Nuclear Station Duke Energy Carolinas, LLC 4800 Concord Road York, SC 29745
SUBJECT:
CATAWBA NUCLEAR STATION, UNITS 1 AND 2 - AUTHORIZATION OF PROPOSED ALTERNATIVE RA-25-0064 FOR INSERVICE TESTING INTERVAL CODE OF RECORD (EPID L-2025-LLR-0072)
Dear Mr. Huecker:
By letter dated July 24, 2025, Duke Energy Carolinas, LLC (Duke Energy, the licensee) submitted a relief request (RA-25-0064) proposing an alternative to the requirements of Title 10 of the Code of Federal Regulations (10 CFR) Section 50.55a(f)(4)(ii) for the Catawba Nuclear Station, Units 1 and 2 (Catawba). The proposed alternative would allow use of the 2020 Edition of the American Society of Mechanical Engineers (ASME) Operation and Maintenance (OM)
Code for the Fifth and Sixth Inservice Testing (IST) intervals, in lieu of the 2022 Edition currently required by regulation.
Pursuant to 10 CFR 50.55a(z)(1), the licensee requested to use an alternative on the basis that use of the 2020 Edition provides an acceptable level of quality and safety.
The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the subject request and concludes, as set forth in the enclosed safety evaluation, that Duke Energy has adequately addressed all of the regulatory requirements set forth in 10 CFR 50.55a(z)(1) and that RA 0064 provides an acceptable level of quality and safety. Therefore, the NRC staff authorizes the alternative as requested in RA-25-0064.
If you have any questions, please contact Shawn Williams, Senior Licensing Project Manager, at Shawn.Williams@nrc.gov.
Sincerely, Michael T. Markley, Branch Chief Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos.
50-413, 50-414
Enclosure:
Safety Evaluation cc: Listserv MICHAEL MARKLEY Digitally signed by MICHAEL MARKLEY Date: 2026.01.08 11:49:54 -05'00'
Enclosure SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION AUTHORIZATION OF ALTERNATIVE NO. RA-25-0064 FOR INSERVICE TESTING INTERVAL CODE OF RECORD DUKE ENERGY CAROLINAS, LLC CATAWBA NUCLEAR STATION, UNITS 1 AND 2 DOCKET NOS. 50-413 and 50-414
1.0 INTRODUCTION
By letter dated July 24, 2025 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML25206A082), Duke Energy (licensee) submitted a request (RA 0064) proposing an alternative to Title 10 of the Code of Federal Regulations (10 CFR)
Section 50.55a(f)(4)(ii) for Catawba Nuclear Station, Units 1 and 2 (Catawba). The proposed alternative would allow use of the 2020 Edition of the American Society of Mechanical Engineers (ASME) Operation and Maintenance of Nuclear Power Plants, Division 1, OM Code:
Section IST (OM Code) for the Fifth and Sixth Inservice Testing (IST) intervals at Catawba, in lieu of the 2022 Edition of the ASME OM Code currently required in 10 CFR 50.55a.
Pursuant to 10 CFR 50.55a(z)(1), the licensee requested to use an alternative on the basis that use of the 2020 Edition provides an acceptable level of quality and safety.
2.0 REGULATORY EVALUATION
The NRC regulations in 10 CFR 50.55a(b)(3) state, in part, that:
Conditions on ASME OM Code. As used in this section, references to the ASME OM Code are to the ASME OM Code, Subsections ISTA, ISTB, ISTC, ISTD, ISTE, and ISTF; Mandatory Appendices I, II, III, IV, and V; and Nonmandatory Appendices A through H and J through M, in the 1995 Edition through the latest edition and addenda of the ASME OM Code incorporated by reference in paragraph (a)(1)(iv) of this section.
Mandatory appendices must be used if required by the OM Code; nonmandatory appendices are approved for use by the NRC but need not be used. When implementing the ASME OM Code, conditions are applicable only as specified in the following paragraphs:
The NRC regulations in 10 CFR 50.55a(f)(4), Inservice testing standards requirement for operating plants, state, in part, that:
Throughout the service life of a boiling or pressurized water-cooled nuclear power facility, pumps and valves that are within the scope of the ASME OM Code must meet the inservice test requirements (except design and access provisions) set forth in the ASME OM Code and addenda that become effective subsequent to editions and addenda specified in [10 CFR 50.55a(f)(2) and (3)] and that are incorporated by reference in [10 CFR 50.55a(a)(1)(iv)], to the extent practical within the limitations of design, geometry, and materials of construction of the components.
The NRC regulations in 10 CFR 50.55a(f)(4)(ii) state:
Applicable IST Code: Successive code of record intervals. Inservice tests to verify operational readiness of pumps and valves, whose function is required for safety, conducted during successive code of record intervals must comply with the requirements of the latest edition and addenda of the ASME OM Code incorporated by reference in paragraph (a)(1)(iv) of this section no more than 18 months before the start of the code of record interval (or the optional ASME Code Cases listed in NRC Regulatory Guide 1.147 or NRC Regulatory Guide 1.192 as incorporated by reference in paragraphs (a)(3)(ii) and (iii) of this section, respectively), subject to the conditions listed in paragraph (b) of this section.
The NRC regulations in 10 CFR 50.55a(f)(7) state:
Inservice Testing Program Test and Examination Plans (IST Plans) for pumps, valves, and dynamic restraints (snubbers) prepared to meet the requirements of the ASME OM Code must be submitted to the NRC as specified in § 50.4. IST Plans must be submitted within 90 days of their implementation for the applicable inservice examination and test interval. Electronic submission is preferred.
The NRC regulations in 10 CFR 50.55a(y) state, in part, that:
(y) Definitions. As used in this section:
Code of record interval means the period of time between the code of record updates required by paragraphs (f)(4) and (g)(4) of this section for the inservice examination and test programs and inservice inspection programs, respectively.
(1) For licensees with codes of record prior to ASME BPV Code,Section XI, 2017 Edition, and OM Code, 2017 Edition, as incorporated by reference in paragraph (a) of this section, the code of record interval is the same as the inservice inspection interval or inservice examination and test interval.
(2) For licensees with codes of record of ASME BPV Code,Section XI, 2017 Edition and OM Code, 2017 Edition, or later, as incorporated by reference in paragraph (a) of this section, the code of record interval is two consecutive inservice inspection or inservice examination and test intervals.
The NRC regulations in 10 CFR 50.55a(z), Alternatives to codes and standards requirements, state:
Alternatives to the requirements of [10 CFR 50.55a(b) through (h)] or portions thereof may be used when authorized by the Director, Office of Nuclear Reactor Regulation. A proposed alternative must be submitted and authorized prior to implementation. The applicant or licensee must demonstrate that:
(1) Acceptable level of quality and safety. The proposed alternative would provide an acceptable level of quality and safety; or (2) Hardship without a compensating increase in quality and safety. Compliance with the specified requirements of this section would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.
3.0 TECHNICAL EVALUATION
3.1 Licensees Code of Record Alternative Request Applicable ASME OM Code Edition The current Code of Record for the Fifth IST Interval applicable to Catawba, Units 1 and 2, is the 2022 Edition of the ASME OM Code as incorporated by reference in 10 CFR 50.55a. The Fifth IST interval for Catawba is scheduled to begin on August 19, 2026. In this request, the licensee is proposing to implement the 2020 Edition of the ASME OM Code as incorporated by reference in 10 CFR 50.55a in lieu of the 2022 Edition of the ASME OM Code.
Applicable ASME OM Code Components The applicable ASME OM Code components for this alternative request are the components specified in the IST Program Plan for the Fifth IST interval for Catawba to be submitted by the licensee as required by 10 CFR 50.55a(f)(7).
Applicable ASME OM Code Requirements The applicable ASME OM Code requirements to this alternative request are specified in the 2020 Edition and 2022 Edition of the ASME OM Code as incorporated by reference in 10 CFR 50.55a.
Licensees Proposed Alternative Pursuant to 10 CFR 50.55a(z)(1), the Catawba licensee proposes to update the IST Program to implement the 2020 Edition of ASME OM Code as incorporated by reference in 10 CFR 50.55a for the Fifth IST interval, rather than the 2022 Edition of the ASME OM Code, as an alternative to the requirements of 10 CFR 50.55a(f)(4)(ii). The start date for the Fifth IST interval will remain August 19, 2026.
Licensees Basis for Use In its submittal dated July 24, 2025, the licensee states, in part, that:
This is being requested to maintain Catawba and McGuire on the same edition of the ASME OM Code. This will allow Duke Energy to maintain a higher level of standardization between the McGuire and Catawba IST Programs.
The interval update project for both stations has already been budgeted and scheduled.
Update contracts were awarded, and work has commenced with tasks completed for both sites based on the 2020 Edition of ASME OM Code. Due to the required number of changes needed, Catawba has extended the Fourth IST Interval by one year, as allowed by ASME OM Code-2004/2006, ISTA-3120(d) to August 19, 2026. Updating Catawba to the 2022 Edition of the OM Code would require additional effort that was not planned or budgeted when the update project began. It will also require Duke Energy to maintain IST programs for the two similarly designed plants with slightly different code requirements. As Catawba and McGuire share Operating Experience and resources between sites, utilizing a common set of code requirements would minimize the risk of errors during program development and implementation.
Although the OM Code 2022 Edition includes changes from the 2020 Edition, both editions continue to ensure an acceptable level of quality and safety. Furthermore, the changes did not address any deficiencies in the Code that adversely impacted safety.
The most recent update to 10 CFR 50.55a (Reference 8.3) by the NRC does not require facilities utilizing earlier editions and addenda to implement any new provisions from the 2022 Edition. A thorough comparison of the 2020 and 2022 Editions revealed some minor changes around pump vibration and check valve trending, as well as MOV Diagnostic analysis, but most of the changes were to provide clarification or to incorporate previous NRC conditions directly into the code. There were no changes that were necessary to ensure acceptable quality and safety standards, nor were any revisions made to correct deficiencies present in the 2020 Edition.
Duke Energy believes that updating the Catawba IST Programs to the 2020 Edition to be consistent with the McGuire IST Program, which entered its new interval in March 2025, will improve the level of quality and safety at both stations. This enables utilizing knowledge from both sites for IST activities, including program development, planning, scheduling, testing, and assessment, thereby providing Duke Energy with extensive experience to reference.
Based on the above, Duke Energy requests authorization for the proposed alternative pursuant to 10 CFR 50.55a(z)(1) on the basis that it provides an acceptable level of quality and safety.
Licensees Reason for Request In its submittal dated July 24, 2025, the licensee states, in part, that:
The Catawba Nuclear Station Fifth IST Interval was originally scheduled to start August 19, 2025. To allow sufficient time to implement the significant changes required to update to the OM Code-2020 Edition, Catawba also extended the Fourth IST Interval by one year, as allowed by ASME OM Code-2004/2006, ISTA-3120(d). This results in a new scheduled Fifth IST Interval start date of August 19, 2026.
However, the latest change to 10 CFR 50.55a to incorporate a new ASME Code edition was published in the Federal Register on August 30, 2024 (Reference 8.3), with an effective date of September 30, 2024. This update incorporates by reference the OM Code-2022 Edition in 10 CFR 50.55a(a)(1)(iv). This published/effective date was earlier than the NRC originally scheduled and requires Catawba Nuclear Station to either a) fully implement the requirements of OM Code 2020 Edition on or before March 30, 2026 due to the 18-month requirement OR b) fully implement the requirements of OM Code 2022 Edition by August 19, 2026 in accordance with 10 CFR 50.55a(f)(4)(ii).
In addition to the fact that the interval update process is already underway, utilizing the OM Code-2020 Edition, Catawba Nuclear Station would also benefit from maintaining consistency with the McGuire Nuclear Station, which also recently updated to the OM Code-2020 Edition. While not identical, Duke Energys Catawba Nuclear Station and McGuire Nuclear Station share many design characteristics; they are both Westinghouse 4 loop Ice Condenser plants with smaller containments and many nearidentical safety systems. As such, the IST Programs are very similar, and it would be beneficial for the purpose of sharing resources and information across sites if both sites are licensed to the same edition of the OM Code.
Duration of Request This proposed alternative will be implemented for the upcoming Code of Record Interval for the IST Program at Catawba. The licensee plans to apply the Code of Record Interval for both the Fifth and Sixth IST intervals at Catawba as defined in 10 CFR 50.55a(y)(2).
3.2
NRC Staff Evaluation
Pursuant to 10 CFR 50.55a(z)(1), the licensee proposes to update the Code of Record for the Fifth IST interval at Catawba to the 2020 Edition of ASME OM Code as incorporated by reference in 10 CFR 50.55a rather than the 2022 Edition of the ASME OM Code that is required by 10 CFR 50.55a(f)(4)(ii). The Fifth IST interval at Catawba is scheduled to begin on August 19, 2026. The licensee requests that this alternative also apply to the Sixth IST interval at Catawba upon completion of the Fifth IST interval. The scope of this request applies to the components specified in the IST Program Plan for the Fifth IST interval (and subsequently the Sixth IST interval) required to be submitted by the licensee for Catawba in accordance with 10 CFR 50.55a(f)(7).
The licensee is requesting this alternative to allow Catawba to implement the same edition of the ASME OM Code as currently being applied at McGuire to standardize their IST Programs to the extent possible. Both Catawba and McGuire are operated by the same licensee. Catawba and McGuire are Westinghouse 4-loop Ice Condenser nuclear power plants with small containments, and almost identical safety systems. With Catawba and McGuire having the same design, the licensee would benefit from implementing the same edition of the ASME OM Code as incorporated by reference in 10 CFR 50.55a as the Code of Record for the Catawba and McGuire IST Programs to share resources and important IST and operating experience information. The licensee also notes that the IST Program update process for Catawba began when 10 CFR 50.55a required the use of the 2020 Edition of the ASME OM Code, such that significant resources have already been expended in developing the new IST Program for Catawba based on the 2020 Edition of the ASME OM Code.
For the continual improvement of nuclear power plant safety, the NRC regulations specify that licensees periodically update their IST Programs to the required latest edition of the ASME OM Code as incorporated by reference in 10 CFR 50.55a.The NRC has emphasized the importance of periodic updates to IST Programs to incorporate the requirements in recent editions of the ASME OM Code to provide safety improvements in the performance of IST activities at nuclear power plants. The NRC staff discussed this Commission position in SECY-00-0011 (dated January 14, 2000), Evaluation of the Requirement for Licensees to Update their Inservice Inspection and Inservice Testing Programs Every 120 Months, (ML003676622) and its Staff Requirements Memorandum (dated April 13, 2000) (ML003702722).Duke Energy recognized the need for a strong justification for its proposed alternative to implement the 2020 Edition of the ASME OM Code when updating the IST Program at Catawba rather than the 2022 Edition of the ASME OM Code as required by 10 CFR 50.55a(f)(4)(ii).
As part of its review of the licensees proposed alternative, the NRC staff compared the IST requirements specified in the 2022 Edition of the ASME OM Code to the 2020 Edition of the ASME OM Code. For example, improvements in the 2022 Edition of the ASME OM Code from the 2020 Edition of the ASME OM Code include the following:
- a. Subsection ISTA, General Requirements, paragraph ISTA-2000, Definitions, specifies definitions for accident and safe shutdown.
- b. Subsection ISTB, Inservice Testing of Pumps in Water-Cooled Reactor Nuclear Power Plants - Pre-2000 Plants, paragraph ISTB-3300. Reference Values, includes vibration reference values for certain smooth running pumps.
- c. Subsection ISTB, paragraph ISTB-3510, General, and related tables, provide updated provisions for vibration monitoring of pumps.
- d. Subsection ISTB, paragraph ISTB-3540, Vibration, includes a new paragraph (e) with trending provisions for pumps that use a minimum reference value with notes added to the applicable tables.
- e. Subsection ISTC, Inservice Testing of Valves in Water-Cooled Reactor Nuclear Power Plants, Table ISTC-3500-1, Inservice Test Requirements, has been revised to indicate specific valve types for the IST Program.
- f.
Subsection ISTD, Preservice and Inservice Requirements for Dynamic Restraints (Snubbers) in Water-Cooled Reactor Nuclear Power Plants, paragraph ISTD-4200, Inservice Examination, and its subparagraphs, provide updated provisions for the inservice examination of snubbers in the IST Program.
- g. Appendix II, Check Valve Condition-Monitoring Program, Section II-1100, Supplemental Definitions, provides a definition of trendable attribute for the implementation of a check valve condition monitoring program.
- h. Appendix III, Preservice and Inservice Testing of Active Electric Motor-Operated Valve Assemblies in Water-Cooled Reactor Nuclear Power Plants, includes changes to address certain regulatory conditions in 10 CFR 50.55a(b)(3)(ii).
- i.
Appendix III, Section III-6200, Analysis of Data, Section III-6300, Evaluation of Data, and Section III-9200, Documentation of Analysis and Evaluation of Data, update the provisions for the qualification of applicable personnel for analyzing and evaluating MOV diagnostic test data.
Based on the above, the NRC staff finds the licensees alternative request to implement the 2020 Edition of the ASME OM Code as the Code of Record for the IST Program at Catawba in lieu of the 2022 Edition of the ASME OM Code as required by 10 CFR 50.55a(f)(4)(ii) to represent a unique set of circumstances. In particular, the licensee is requesting to use the 2020 Edition of the ASME OM Code as the Code of Record for the IST Program at Catawba to be consistent with the IST Program at McGuire. Catawba and McGuire are operated by the same licensee. Further, these two nuclear power plants have a Westinghouse 4-loop Ice Condenser design with a smaller containment that differs from the design of other nuclear power plants and have almost identical safety systems. With this alternative, the licensee plans to standardize the IST Programs at Catawba and McGuire to the extent possible to share resources and IST and operating experience information that will provide increased safety at both nuclear power plants.
The NRC staff recognizes that the licensee has already expended considerable resources to begin the IST Program update process for Catawba when 10 CFR 50.55a required the use of the 2020 Edition of the ASME OM Code. The NRC staff agrees that there is a safety benefit and efficiency in implementing consistent IST Programs at Catawba and McGuire based on the 2020 Edition of the ASME OM Code as incorporated by reference in 10 CFR 50.55a. The sharing of resources and important information is sufficient to justify the safety benefit of the improvements in the 2022 Edition of the ASME OM Code from the 2020 Edition of the ASME OM Code. Based on the above, the NRC staff finds that the alternative request by the licensee to implement the 2020 Edition of the ASME OM Code as incorporated by reference in 10 CFR 50.55a as the next Code of Record for the IST Program at Catawba will provide an acceptable level of quality and safety in accordance with 10 CFR 50.55a(z)(1).
The NRC staff notes that ASME OM Code (2020 Edition), Subsection ISTA, paragraph ISTA-3120, Inservice Examination and Test Interval, as incorporated by reference in 10 CFR 50.55a, requires that licensees implement 10-year intervals for their IST programs.
ASME OM Code Case OMN-31, Alternative to Allow Extension of ISTA-3120 Inservice Examination and Test Intervals from 10 to 12 Years, is conditionally accepted in Revision 5 to RG 1.192, which the licensee could voluntarily implement to extend their IST intervals from 10 to 12 years, if the conditions in RG 1.192 are satisfied. The NRC regulations in 10 CFR 50.55a allow licensees to implement the same ASME OM Code as their Code of Record for two successive IST program intervals. The licensee proposes to apply the 2020 Edition of the ASME OM Code, as incorporated by reference in 10 CFR 50.55a for both the Fifth and Sixth IST intervals at Catawba. Based on the NRCs authorization of this request, Duke Energy is permitted to implement the 2020 Edition of the ASME OM Code, as incorporated by reference in 10 CFR 50.55a, as the Code of Record for both the Fifth and Sixth IST intervals at Catawba, in accordance with ASME OM Code, Subsection ISTA, paragraph ISTA-3120.
4.0 CONCLUSION
Based on its review discussed above, the NRC staff concludes that the alternative request by the licensee to implement the 2020 Edition of the ASME OM Code as incorporated by reference in 10 CFR 50.55a as the next Code of Record for the IST Program at Catawba in lieu of the 2022 Edition of the ASME OM Code required by 10 CFR 50.55a(f)(4)(ii) will provide an acceptable level of quality and safety. This alternative applies to the components specified in the IST Program Plan for the Fifth IST interval (and subsequently the Sixth IST interval) required to be submitted by the licensee for Catawba by 10 CFR 50.55a(f)(7). Therefore, the NRC staff authorizes this alternative in accordance with 10 CFR 50.55a(z)(1).
All other ASME OM Code requirements as incorporated by reference in 10 CFR 50.55a for which relief or an alternative was not specifically requested and granted or authorized (as appropriate) remain applicable.
Principal Contributors: Thomas G. Scarbrough Nicholas J. Hansing Date: January 8, 2026
ML26005A084 NRR-028 OFFICE NRR/DORL/LPL2-1/PM NRR/DORL/LPL2-1/LA NRR/DNRL/EMIB/BC NAME SWilliams KZeleznock SBailey DATE 1/2/2026 1/7/2026 12/22/2025 OFFICE NRR/DORL/LPL2-1/BC NAME MMarkley DATE 1/8/2026