ML25070A151
| ML25070A151 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 03/20/2025 |
| From: | Tony Nakanishi Plant Licensing Branch IV |
| To: | Schuetz R Energy Northwest |
| Chawla M | |
| References | |
| EPID L-2024-LLR-0039 | |
| Download: ML25070A151 (1) | |
Text
March 20, 2025 Robert Schuetz Chief Executive Officer Energy Northwest 76 North Power Plant Loop P.O. Box 968 (Mail Drop 1023)
Richland, WA 99352
SUBJECT:
COLUMBIA GENERATING STATION - ALTERNATIVE REQUEST 4IST-12 (RV-05) FOURTH INTERVAL INSERVICE TESTING PROGRAM (EPID L-2024-LLR-0039)
Dear Robert Schuetz:
By letter dated June 11, 2024 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML24164A214), as supplemented by letter dated November 4, 2024 (ML24310A123), Energy Northwest (the licensee) submitted Alternative Request 4IST-12 (RV-05) to the U.S. Nuclear Regulatory Commission (NRC) proposing the use of an alternative to specific inservice testing (IST) requirements in the 2004 Edition through 2006 Addenda of the American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code), associated with the fourth interval IST program at Columbia Generating Station (Columbia).
Specifically, pursuant to Title 10 of the Code of Federal Regulations (10 CFR)
Section 50.55a(z)(1), the licensee requests to implement Alternative Request 4IST-12 (RV-05) on the basis that the proposed alternative would provide an acceptable level of quality and safety.
At the time of the initial submittal dated June 11, 2024, the Columbia fourth interval IST program, which began on December 13, 2014, was scheduled to end on December 12, 2024. In a letter dated July 15, 2024 (ML24197A223), the licensee notified the NRC of its plan to extend the end date of Columbia fourth interval IST program by 1 year as allowed by the ASME OM Code, subsection ISTA, General Requirements, paragraph ISTA-3120, Inservice Examination and Test Interval, which allows an extension of the interval end date not to exceed 1 year cumulatively. Therefore, the licensee proposed Alternative Request 4IST-12 (RV-05) to be authorized for the remainder of the fourth interval IST program ending on December 12, 2025.
The NRC staff has determined that Alternative Request 4IST-12 (RV-05) provides an acceptable level of quality and safety for the proposed testing for the specified containment isolation valves for the remainder of the fourth interval IST program at Columbia. Accordingly, the NRC staff concludes that the licensee has adequately addressed the regulatory requirements set forth in 10 CFR 50.55a(z)(1). Therefore, the NRC staff authorizes the use of Alternative Request 4IST-12 (RV-05) at Columbia for the remainder of the fourth interval IST program, which began on December 13, 2014, and is scheduled to end on December 12, 2025.
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), in the subject request remain applicable.
If you have any questions please contact the Project Manager, Mahesh Chawla, at (301) 415-8371 or via email at Mahesh.Chawla@nrc.gov.
Sincerely, Tony Nakanishi, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-397
Enclosure:
Safety Evaluation cc: Listserv TONY NAKANISHI Digitally signed by TONY NAKANISHI Date: 2025.03.20 09:08:53 -04'00'
Enclosure SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION ALTERNATIVE REQUEST 4IST-12 (RV-05)
FOURTH INTERVAL INSERVICE TESTING PROGRAM ENERGY NORTHWEST COLUMBIA GENERATING STATION DOCKET NO. 50-397
1.0 INTRODUCTION
By letter dated June 11, 2024 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML24164A214), as supplemented by letter dated November 4, 2024 (ML24310A123), Energy Northwest (the licensee) submitted Alternative Request 4IST-12 (RV-05) to the U.S. Nuclear Regulatory Commission (NRC) proposing the use of an alternative to specific inservice testing (IST) requirements in the 2004 Edition through 2006 Addenda of the American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code), associated with the fourth interval IST program at Columbia Generating Station (Columbia).
Specifically, pursuant to Title 10 of the Code of Federal Regulations (10 CFR)
Section 50.55a(z)(1), Acceptable level of quality and safety, the licensee requests to implement Alternative Request 4IST-12 (RV-05) on the basis that the proposed alternative would provide an acceptable level of quality and safety.
At the time of the initial submittal dated June 11, 2024, the Columbia fourth interval IST program, which began on December 13, 2014, was scheduled to end on December 12, 2024. In a letter dated July 15, 2024 (ML24197A223), the licensee notified the NRC of its plan to extend the end date of Columbia fourth interval IST program by 1 year as allowed by the ASME OM Code, subsection ISTA, General Requirements, paragraph ISTA-3120, Inservice Examination and Test Interval, which allows an extension of the interval end date not to exceed 1 year cumulatively. Therefore, the licensee proposed Alternative Request 4IST-12 (RV-05) be authorized for remainder of the fourth interval IST program ending on December 12, 2025.
2.0 REGULATORY EVALUATION
The NRC regulations in 10 CFR 50.55a(f)(4), Inservice testing standards requirement for operating plants, state, in part:
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(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.
Columbia Technical Specification (TS) 5.5, Program and Manual, section 5.5.12, Primary Containment Leakage Rate Testing Program, states:
The Primary Containment Leakage Rate Testing Program shall establish the leakage rate testing of the containment as required by 10 CFR 50.54(0) and 10 CFR 50, Appendix J, Option B, as modified by approved exemptions. This program shall be in accordance with the guidelines contained in NEI 94-01, Industry Guideline for Implementing Performance-Based option of 10 CFR Part 50, Appendix J, Revision 3-A, dated July 2012, and the conditions and limitations specified in NEI 94-01, Revision 2-A, dated October 2008.
3.0 TECHNICAL EVALUATION
3.1 Licensees Alternative Request 4IST-12 (RV-05)
Applicable ASME OM Code Edition The applicable ASME OM Code of record for the fourth interval IST program at Columbia is the 2004 Edition through 2006 Addenda of ASME OM Code, as incorporated by reference in 10 CFR 50.55a, Codes and standards.
Applicable ASME Code Components In its submittal, the licensee proposed alternative testing for the following containment isolation valves (CIVs):
Applicable Valve ASME Class ASME OM Code Category System CSP-V-93 2
A CONTAINMENT SUPPLY PURGE CSP-V-96 2
A CSP-V-97 2
A CSP-V-98 2
A PI-VX-250*
2 A
PROCESS INSTRUMENTATION PI-VX-251*
2 A
PI-VX-253*
2 A
PI-VX-256*
2 A
PI-VX-257*
2 A
PI-VX-259*
2 A
PSR-V-X73/1 2
A PRIMARY SAMPLING RADIOACTIVE PSR-V-X73/2 2
A PSR-V-X77A/1 1
A PSR-V-X77A/2 1
A PSR-V-X77A/3 1
A PSR-V-X77A/4 1
A PSR-V-X80/1 2
A PSR-V-X80/2 2
A PSR-V-X82/1 2
A PSR-V-X82/2 2
A PSR-V-X82/7 2
A PSR-V-X82/8 2
A PSR-V-X83/1 2
A PSR-V-X83/2 2
A PSR-V-X84/1 2
A PSR-V-X84/2 2
A PSR-V-X88/1 2
A PSR-V-X88/2 2
A TIP-V-1*
2 A
TRAVERSING IN-CORE PROBE TIP-V-2*
2 A
TIP-V-3*
2 A
TIP-V-4*
2 A
TIP-V-5*
2 A
TIP-V-15 2
A
- Alternative is requested for only the close position verification testing frequency. The open position verification will remain on a 2-year testing frequency.
Note 1: Valve categories are defined per ASME OM Code, subsection ISTC, Inservice Testing of Valves in Light-Water-Cooled Reactor Nuclear Power Plants, paragraph ISTC-1300, Valve Categories. subparagraph (a), states that, Category A: valves for which seat leakage is limited to a specific maximum amount in the closed position for fulfillment of their required function(s),
as specified in ISTA-1100.
Applicable ASME OM Code Requirements The IST requirements in the ASME OM Code, 2004 Edition through 2006 Addenda, as incorporated by reference in 10 CFR 50.55a, related to this alternative request are as follows:
ASME OM Code, subsection ISTC, paragraph ISTC-3700, Position Verification Testing, states:
Valves with remote position indicators shall be observed locally at least once every 2 yr [years] to verify that valve operation is accurately indicated. Where practicable, this local observation should be supplemented by other indications such as use of flow meters or other suitable instrumentation to verify obturator position. These observations need not be concurrent. Where local observation is not possible, other indications shall be used for verification of valve operation.
ASME OM Code, paragraph ISTC-3530, Valve Obturator Movement, states:
The necessary valve obturator movement shall be determined by exercising the valve while observing the and appropriate indicator, such that indicating lights that signal the required changes of obturation position, or by observing the other evidence, such as changes in system pressure, flow rate, level, or temperature, that reflects change of obturator position.
Licensees Proposed Alternative As an alternative to the ISTC-3700 test interval of at least once every 2 years, the licensee proposes that the verification position indication (VPI) testing of the CIVs listed in this safety evaluation (SE) be performed in conjunction with the local leak rate testing (LLRT) at a frequency in accordance with 10 CFR Part 50, Appendix J, Option B. The NRC approved a Columbia license amendment request (LAR) to utilize this performance-based option for the primary containment leakage rate testing (CLRT) program in Columbia TS section 5.5.12 by an NRC letter dated March 30, 2018 (ML18052B185). Option B of 10 CFR Part 50, Appendix J, permits the extension of the Appendix J seat leakage testing to a frequency corresponding to the specific valve performance. Valves whose leakage test results indicate good performance may have their testing interval increased based on these test results, not to exceed 75 months.
The Columbia CLRT program, which implements 10 CFR Part 50, Appendix J, Option B, requires individual CIVs to pass two successful as-found seat leakage tests before they can be placed on extended seat leakage testing frequency. In the event a valve cannot meet the test criteria for Appendix J leakage, or the occurrence of a VPI test failure, the surveillance interval would be reset to the base frequency of 24 months. Only after three consecutive as-found tests in consecutive refueling outages with acceptable results would the frequency be returned to an extended interval. In its submittal dated June 11, 2024, the licensee provides test results from the most recent refueling outages, demonstrating good performance of the valves.
The licensee states that in addition to the VPI and seat leakage testing, each of the valves listed in this SE is exercised on a quarterly frequency. The valve stroke times are measured and compared to the ASME OM Code acceptance criteria, providing further data for Columbia personnel to use for assessing the health of the valves. The licensee considers that this multi-faceted approach to testing provides Columbia with ample opportunity to assess valve performance. Therefore, the ability to detect valve degradation is not jeopardized by performing the VPI testing at the same frequency as specified by 10 CFR Part 50, Appendix J, Option B.
The licensee asserts that this frequency of testing provides reasonable assurance of the operational readiness of the valves and provides an acceptable level of quality and safety.
Licensees Reason for Request In its letter dated June 11, 2024, the licensee states the reason for the alternative request as follows:
Pursuant to 10 CFR 50.55a, Codes and Standards, paragraph (a)(3), relief is requested from the requirement of ASME OM Code ISTC-3700 for the valves identified in Section 1 of this submittal. Specifically, Energy Northwest requests relief from performing the verification position indication (VPI) testing at the two-year frequency mandated by ISTC-3700. The basis of the relief is that the proposed alternative would provide an acceptable level of quality and safety.
The valves listed in Section 1 are containment isolation valves classified as Category A per ISTC-1300, Inservice Testing of Valves in Water-Cooled Reactor Nuclear Power Plants. The subject valves have a safety function to close to isolate containment during a loss of coolant accident requiring containment isolation. These solenoid-operated valves are designed such that the position of the valve is not locally observable; the coil position is internal to the valve body and is not visible in either the energized or de-energized state.
ISTC-3700 contains an allowance that states, Where local observation is not possible, other indications shall be used for verification of valve operation. The VPI test method used at Columbia is a pressure test utilizing local leak rate testing (LLRT) equipment. This method involves pressurizing the containment penetration volume to approximately 38 psi [per square inch], and verifying the penetration remains pressurized while the valve is indicating closed on the main control room panel. The valve is then opened using the control switch in the main control room. The increase in flowrate is measured, along with the valve position indicating open in the main control room. This method satisfies the requirement for position indication verification and ensures that the indicating system accurately reflects the valve position.
The VPI test at Columbia is performed concurrently with the LLRT since both tests utilize the same testing equipment. To properly complete the testing, each individual valve must have its system thoroughly drained, vented, and aligned correctly, which results in unnecessary radiation exposure, as well as a significant impact to Operations and Maintenance personnel time. Decreasing the frequency of the VPI testing would result in dose savings and reductions in both staff labor and plant component manipulations.
In a clarification letter dated November 4, 2024, the licensee provided the following information:
With License Amendment 247, Energy Northwest was approved to utilize Nuclear Energy Institute (NEI) 94-01, Revision 3-A, Industry Guideline for Implementing Performance-Based Option of 10 CFR Part 50, Appendix J, which delineates a performance-based approach for surveillance testing frequencies. The ability to extend surveillance frequencies for these components is based on performance history of the component and risk insights. This same allowance was not approved for Inservice Testing (IST) components, leaving the IST components to continue following testing frequency requirements of American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear power Plants (OM Code), 2004 Edition through 2006 Addenda.
Energy Northwest is requesting relief from the ASME OM Code frequency requirements, and will apply the NEI 94-01, Revision 3-A, guidance, as well as the conditions and limitations specified in NEI 94-01, Revision 2-A, to the valve position indication (VPI) testing frequencies for the IST components listed in Alternative Request 4IST-12. This approval will align the VPI testing frequencies to those of the 10 CFR Part 50, Appendix J components. The VPI testing frequency for the applicable components will be eligible for performance-based testing interval extension, in accordance with NEI 94-01, Revision 3-A. If a component exceeds its administrative limit or fails its VPI testing, the surveillance will be reset to the base frequency of 30 months. Only after meeting the requirements of NEI 94-01, Revision 3-A, would the frequency be eligible for an extended interval. Energy Northwests 10 CFR Part 50, Appendix J, Option B performance-based leakage testing program will govern VPI testing interval frequency for the approved components in lieu of the testing frequency requirements in ASME OM Code, 2004 Edition through 2006 Addenda, Subsection ISTC-3700, Position Verification Testing.
3.2
NRC Staff Evaluation
The ASME OM Code requires active and passive valves to be periodically tested in accordance with subsection ISTC, paragraph ISTC-3500, Valve Testing Requirements. Active valves are exercised at a frequency determined by subsection ISTC, paragraph ISTC-3510, Exercising Test Frequency. Valves are nominally exercised every 3 months except where the exercise is not practicable when the plant is operating. During the valve exercise, valve obturator movement is verified by paragraph ISTC-3530, which allows the use of remote position indicating lights that signal the required change of obturator position to complete this test.
However, the use of remote position indicating lights does not provide a positive verification that the valve operation is accurately indicated. To address this, ASME OM Code, subsection ISTC, paragraph ISTC-3700, requires local observation of the valve exercise every 2 years to verify valve operation is accurately indicated.
The licensee has proposed an alternative test in lieu of the applicable requirements of 2004 Edition through 2006 Addenda of the ASME OM Code for the CIVs listed in this SE. Specifically, the licensee proposes to perform the VPI testing in conjunction with the Type C tests (which measure CIV leakage rates) at a frequency in accordance with the 10 CFR Part 50, Appendix J, Option B schedule. Under this approach, valves would initially be tested at the required interval schedule, which is currently every refueling outage (every 2 years), or an interval as specified by ISTC-3700. Valves that have demonstrated good performance for two consecutive cycles may have their test interval extended to a maximum of 75 months. Good performance is defined as no VPI test failures due to seating surface condition of the valves. Any leakage test failure would require the component to return to the initial interval until good performance can again be established.
The NRC approved a Columbia LAR to implement a performance-based option for the CLRT program in the Columbia TS section 5.5.12 by letter dated March 30, 2018 (ML18052B185).
Option B of 10 CFR Part 50, Appendix J, permits the extension of the Appendix J seat leakage testing to a frequency corresponding to the specific valve performance. The Columbia CLRT program, which implements 10 CFR Part 50, Appendix J, Option B, requires individual CIVs to pass two successful as-found seat leakage tests before it can be placed on extended seat leakage testing frequency. In the event a valve cannot meet test criteria for Appendix J leakage, or a VPI test failure, the surveillance would be reset to the base frequency of 24 months. Only after three consecutive as-found tests in consecutive refueling outages with acceptable results would the frequency be returned to an extended interval. Alternative Request 4IST-12 (RV05) shows successful test results from the most recent refueling outages, which demonstrates good performance of the valves.
Based on its review, the NRC staff finds that the licensee has demonstrated good performance of the CIVs within the scope of Alternative Request 4IST-12 (RV-05) for Columbia. The staff finds that the licensee has justified the proposed Alternative Request 4IST-12 (RV-05) as an alternative to the ISTC-3700 test interval of at least once every 2 years, to perform the VPI testing of the CIVs listed in this SE in conjunction with the LLRT at a frequency in accordance with 10 CFR Part 50, Appendix J, Option B. As a result, the staff finds that Alternative Request 4IST-12 (RV-05) provides an acceptable level of quality and safety in accordance with 10 CFR 50.55a(z)(1).
4.0 CONCLUSION
As set forth above, the NRC staff has determined that Alternative Request 4IST-12 (RV-05) provides an acceptable level of quality and safety for the proposed testing for the specified CIVs for the remainder of the fourth interval IST program at Columbia. Accordingly, the NRC staff concludes that the licensee has adequately addressed the regulatory requirements set forth in 10 CFR 50.55a(z)(1). Therefore, the NRC staff authorizes the use of Alternative Request 4IST-12 (RV-05) at Columbia for the remainder of the fourth interval IST program, which began on December 13, 2014, and is scheduled to end on December 12, 2025.
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), in the subject request remain applicable.
Principal Contributors: Gurjendra S. Bedi, NRR Thomas G. Scarbrough, NRR Date: March 20, 2025
- via email NRR-028 OFFICE NRR/DORL/LPL4/PM*
NRR/DORL/LPL4/LA*
NRR/DEX/EMIB/BC*
NAME MChawla PBlechman SBailey DATE 3/17/2025 3/18/2025 2/19/2025 OFFICE NRR/DORL/LPL4/PM*
NRR/DORL/LPL/BC*
NAME MChawla TNakanishi DATE 3/20/2025 3/20/2025