ML21084A239
| ML21084A239 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 03/24/2021 |
| From: | Mark D. Sartain Dominion Energy Nuclear Connecticut |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 21-082 | |
| Download: ML21084A239 (10) | |
Text
Dominion Energy Nuclear Connecticut, Inc.
5000 Dominion Boulevard, Glen Allen, VA 23060 Dominion DominionEnergy.com Energy March 24, 2021 U.S. Nuclear Regulatory Commission Serial No.21-082 Attention: Document Control Desk NRA/SS RO Washington, DC 20555 Docket No. 50-423 License No. NPF-49 DOMINION ENERGY NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNIT 3 PROPOSED REQUEST FOR ALTERNATIVE FREQUENCY TO SUPPLEMENTAL VALVE POSITION VERIFICATION TESTING REQUIREMENTS In accordance with 10 CFR 50.55a(z)(1 ), Dominion Energy Nuclear Connecticut, Inc.
(DENC) hereby requests Nuclear Regulatory Commission (NRC) approval of a proposed alternative for Millstone Power Station Unit 3 (MPS3). Specifically, DENC proposes an alternative to the American Society of Mechanical Engineers (ASME),
Operation and Maintenance of Nuclear Power Plants Code (OM Code), ISTC-3700 frequency requirement to allow performance of supplemental valve position verification at a frequency consistent with 10 CFR 50, Appendix J Type C testing for the valves within the scope of this request.
This request, which is being submitted on the basis that the proposed alternative provides an acceptable level of quality and safety, is provided in the attachment to this letter. The duration of the proposed alternative is requested for the remainder of MPS3's fourth 10-year inservice testing interval which ends on December 1, 2028.
NRC review and approval of the proposed alternative request is requested by April 1, 2022, to support the upcoming refueling outage scheduled to occur during spring 2022.
If you have any questions or require additional information, please contact Shayan Sinha at (804) 273-4687.
Sincerely, Mark D. Sartain Vice President - Nuclear Engineering & Fleet Support
Serial No.21-082 Docket No. 50-423 Page 2 of 2
Attachment:
Proposed Request for Alternative Frequency to Supplemental Valve Position Verification Testing Requirements Commitments made in this letter: None cc:
U.S. Nuclear Regulatory Commission Region I 2100 Renaissance Blvd, Suite 100 King of Prussia, PA 19406-2713 Mr. Richard V. Guzman NRC Senior Project Manager - Millstone U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 08-C 2 11555 Rockville Pike Rockville, MD 20852-2738 .
NRC Senior Resident Inspector Millstone Power Station
Serial No.21-082 Docket No. 50-423 ATTACHMENT PROPOSED REQUEST FOR ALTERNATIVE FREQUENCY TO SUPPLEMENTAL VALVE POSITION VERIFICATION TESTING REQUIREMENTS MILLSTONE POWER STATION UNIT 3 DOMINION ENERGY NUCLEAR CONNECTICUT, INC.
Serial No.21-082 Docket No. 50-423 Attachment, Page 1 of 7 Valve Alternative Request Number V-01 Millstone Power Station Unit 3 Proposed Request for Alternative Frequency to Supplemental Valve Position Verification Testing Requirements In accordance with 10 CFR 50.55a(z)(1)
Alternative Provides an Acceptable Level of Quality and Safety Dominion Energy Nuclear Connecticut, Inc. (DENC) proposes an alternative to the requirements of American Society of Mechanical Engineers (ASME) Operation and Maintenance (OM) of Nuclear Power Plants, 2012 Edition, ISTC-3700 for Millstone Power Station Unit 3 (MPS3) valves in Table 1. Specifically, the proposed alternative would allow utilization of the containment local leakage testing (LLRT) frequency requirement, such that the scheduled LLRT will satisfy. the requirements for both obturator testing and individual valve Appendix J Type C LLRT.
Valve Description Code Valve Operator Class
- Category 3CMS*CTV20 CTMT ATMOSPHERE MONITOR SUCTION 2 A Pneumatic CTMT PENETRATION {32-OUTSIDE) 3CMS*CTV21 CTMT ATMOSPHERE MONITOR SUCTION 2 A Pneumatic CTMT PENETRATION (32-OUTSIDE) 3CMS *.CTV23 CTMT ATMOSPHERE MONITOR DISCHARGE CTMT 2 A Pneumatic PENETRATION {63-OUTSIDE) 3CVS*AOV23 CTMTVACUUM EJECTOR SUCTION ISOL VLV 2 A Pneumatic CTMT PENETRATION (37-INSIDE) 3CVS*CTV20A CTMT VACUUM PUMP SUCTION 2 A Pneumatic CTMT ISOLATION PENETRATION (35-OUTSIDE) 3CVS*CTV20B CTMT VACUUM PUMP SUCTION 2 A Pneumatic CTMT ISOLATION PENETRATION (36-OUTSIDE) 3CVS*CTV21A CTMTVACUUM PUMP SUCTION 2 A Pneumatic CTMT ISOLATION PENETRATION (35-OUTSIDE) 3CVS*CTV21B CTMT VACUUM PUMP SUCTION 2 A
Serial No.21-082 Docket No. 50-423 Attachment, Page 2 of 7 Table 1 - Scope of Valves ASME OM Valve ID/
Valve Description Code Valve Operator Class Category Pneumatic CTMT ISOLATION PENETRATION (36-0UTSIDE) 3CVS*MOV25 CTMTVACUUM PUMP DISCHARGE 2 A Motor CTMT PENETRATION (121-INSIDE) 3DAS*CTV24 RX PLANT AERATED DRAINS 2 A Pneumatic CTMT PENETRATION (28-INSIDE) 3DAS*CTV25 RX PLANT AERATED DRAINS 2 A Pneumatic CTMT PENETRATION (28-OUTSIDE) 3DGS*CTV24 PRT & CTMT DRAINS TRANSFER PP DSCHRG 2 A Pneumatic CTMT PENETRATION {27-INSIDE) 3DGS*CTV25 PRT & CTMT DRAINS TRNSFR PP DSCHRGE CTMT 2 A Pneumatic PENETRATION (27-OUTSIDE) 3HCS*V002 DBA HYDROGEN RECOMBINER SUPPLY 2 A Manual CTMT PENETRATION (111-OUTSIDE) 3HCS*V003 DBA HYDROGEN RECOMBINER SUPPLY 2 A Manual CTMT PENETRATION (111-OUTSIDE) 3HCS*V006 DBA HYDROGEN RECOMBINER DISCHARGE CTMT 2 A Manual PENETRATION (113-OUTSIDE) 3HCS*V009 DBA HYDROGEN RECOMBINER SUPPLY 2 A Manual CTMT PENETRATION (112-OUTSIDE) 3HCS*V010 DBA HYDROGEN RECOMBINER SUPPLY 2 A Manual CTMT PENETRATION (112-OUTSIDE) 3HCS*V013 DBA HYDROGEN RECOMBINER DISCHARGE CTMT 2 A Manual PENETRATION {114-OUTSIDE)
- 2) Applicable Code Edition American Society of Mechanical Engineers Operation and Maintenance of Nuclear Power Plants, 2012 Edition, No Addenda (Reference 1).
- 3) Applicable Code Requirement(s)
ISTC-3530, Valve Obturator Movement: The necessary valve obturator movement shall be determined by exercising the valve while observing an appropriate indicator,
Serial No.21-082 Docket No. 50-423 Attachment, Page 3 of 7 such as indicating lights that signal the required changes of obturator position, or by observing other evidence, such as changes in system pressure, flow rate, level, or temperature, that reflects change of obturator position. '
ISTC-3700, Position Verification Testing: Valves with remote position indicators shall be observed locally at least once every 2 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.
Position verification for active MOVs [motor-operated valves] shall be tested in accordance with Mandatory Appendix Ill of this Division.
10 CFR 50.55a(b )(3)(xi) states:
OM condition: Valve Position Indication. When implementing paragraph ISTC-3700, "Position Verification Testing," in the ASME OM Code, 2012 Edition through the latest edition and addenda of the ASME OM Code incorporated by reference in paragraph (a)(1 )(iv) of this section, licensees shall verify that valve operation is accurately indicated by supplementing valve position indicating lights with other indications, such as flow meters or other suitable instrumentation to provide assurance of proper obturator position for valves with remote position indication within the scope of Subsection ISTC including its mandatory appendices and their verification methods and frequencies.
- 4) Reason for Request Currently, DENG utilizes procedures developed for the LLRT program per 10 CFR 50, Appendix J (Reference 2) to satisfy the supplemental position verification testing of valve closure for the MPS3 valves listed in Table 1. DENG is performing these activities to meet the Subsection ISTC-3700 of ASME OM Code test frequency requirement. Subsection ISTC-3700 of the ASME OM Code requires obturator testing more frequently than the individual LLRT Type C tests required by 10 CFR 50, Appendix J. DENG proposes an alternative to the provisions of ISTC-3700 to allow utilization of the LLRT test frequency requirement, such that the scheduled LLRT will satisfy the requirements for both obturator testing and individual valve Appendix J Type C LLRT.
Serial No.21-082 Docket No. 50-423 Attachment, Page 4 of 7
- 5) Proposed Alternative and Basis for Use Proposed Alternative Regulation 10 CFR 50.55a(b )(3)(xi) states that licensees shall verify that valve operation is accurately indicated by supplementing valve position indicating lights with other indications, such as flow meters or other suitable instrumentation, to provide assurance of proper obturator position. Subsection ISTC-3700 of ASME OM Code states that supplemental position verification shall be observed at least once every 2 years. For certain valves at MPS3, 10 CFR 50, Appendix J, Type C testing (LLRT) is credited to meet the supplemental position verification closure testing portion of the above requirement. Under License Amendment 276 (Reference 5),
DENG adopted the Appendix J, Performance-Based, Option B Program consistent with NEI 94-01, Revision 3-A, "Industry Guideline for Implementing Performance-Based Option of 10 CFR Part 50, Appendix J (Reference 3)" for MPS3. This program allows LLRT intervals to be extended up to 75 months for valves with a history of satisfactory testing. DENG proposes an alternative to the ASME OM Code, ISTC-3700 requirements, to perform the valve supplemental position verification at a frequency consistent with 10 CFR 50, Appendix J, Type C testing (LLRT) for MPS3.
Basis for Use A review of MPS3's maintenance and code-required performance history concluded that MPS3 valves listed in Table 1 have been reliable. DENG adopted ASME OM Code, 2012 Edition for MPS3 in December 2018. The Code requirements for the valves listed in Table 1 have been met, including (depending on the valve type) supplemental position verification, manual exercise testing, and stroke time testing, etc. The review of recorded performance history for the valves in Table 1, which dated back to 1985, identified no stem-to-disc separation events. This finding was also supported by a search of condition reports dating back to 2008 and by INPO Industry Reporting and Information System (IRIS) searches, which did not identify any stem-to-disc failures of MPS3 valves. Therefore, obtaining supplemental position verification at a test interval longer (less frequent) than the frequencies specified in ASME OM Code, 2012 Edition, and controlled by 10 CFR 50, Appendix J performance-based\ frequency requirements, provides an acceptable level of quality and safety.
- 10 CFR 50, Appendix J, states:
The purposes of the tests are to assure that (a) leakage through the primary reactor containment and systems and components penetrating primary containment shall not exceed allowable leakage rate values as specified in the technical specifications or associated bases; and (b) periodic surveillance of reactor containment penetrations and isolation valves is performed so that proper maintenance and repairs are made during the service life of the containment, and systems and components penetrating primary containment.
Serial No.21-082 Docket No. 50-423 Attachment, Page 5 of 7 The paragraph above describes the 10 CFR 50, Appendix J, role in validating a component's ability to perform, as designed. Valves are subject to strict leakage requirements to assure performance of the overall containment structure. Valves that do not perform acceptably receive maintenance to restore performance.
Performance is validated with subsequent consecutive leakage testing to provide assurance that maintenance is effective and valve performance is satisfactory.
These requirements ensure licensees are effectively protecting the public health and safety by maintaining plant equipment to the specifications established by the plant's design basis and Technical Specifications (TSs). Under License Amendment 276, DENG adopted the Appendix J, Performance-Based, Option B Program consistent with NEI 94-01 Revision 3-A for MPS3. This program allows Type C LLRT intervals to be extended up to 75 months for valves. NRC has endorsed NEI 94-01 Revision 3-A as providing an acceptable level of quality and safety under Regulatory Guide 1.163, Performance-Based Containment Leak-Test Program (Reference 4 ).
Regulation 10 CFR 50, Appendix J, requires more rigorous acceptance criteria than ISTC-3700 and 10 CFR 50.55a(b )(3)(xi). ISTC-3700 and Regulation 10 CFR 50.55a(b )(3)(xi) requires supplemental position verification that "provide[s]
assurance of proper obturator position." ISTC-3700 and 10 CFR 50.55a(b )(3)(xi) direct licensees to obtain evidence of gross flow or closure. MPS3 conforms with Option B, Performance-Based Requirements, of 10 CFR 50, Appendix J and NEI 94-01 Revision 3-A. In contrast to the ASME OM Code, Appendix J, Option B requires acceptance criteria to support the overall containment leakage requirements, which are needed to satisfy TS 3.6.1.2, "Containment Leakage," and TS 6.8.4.f, "Containment Leakage Rate Testing Program." Thus, the ISTC-3700 and 10 CFR 50.55a(b )3(xi) requirement to show evidence of gross flow or closure is bounded by 10 CFR 50, Appendix J, test requirements, which specifically quantify valve leakage acceptance criteria. The requirements of 10 CFR 50, Appendix J and NEI 94-01 Revision 3-A are rigorous, and therefore satisfy the closed supplemental position verification requirements from ISTC-3700 and 10 CFR 50.55a(b )(3)(xi).
Test frequencies in accordance with 10 CFR 50, Appendix J are performance-based. Valves with consistent, acceptable performance qualify for frequency extension up to 7:5 months. Valves must pass two successful as-found leakage tests to qualify for a 75-month test frequency. A valve demonstrates acceptable performance when it exhibits leakage below the assigned administrative limits.
Valves that do not meet the performance standard are tested every refueling interval, in accordance with 10 CFR 50, Appendix J, which is more frequent than the most limiting frequency requirement for supplemental position verification of up to two years. The valves in Table 1 have met the performance standard for extension to a 75-month period, with only two exceptions (3CMS*CTV21 and 3CVS*AOV23).
In December 2018, DENG adopted the ASME OM Code, 2012 Edition requirements for the fourth MPS3 10-year 1ST interval. The NRC has endorsed ASME OM Code, 2012 Edition (Reference 1), as providing an acceptable level of quality and safety.
Regulation 10 CFR 50.55a(a)(1 )(iv), "ASME Operation and Maintenance Code,"
Serial No.21-082 Docket No. 50-423 Attachment, Page 6 of 7 identifies ASME OM Code, 2012 Edition, as an acceptable test methodology, subject to conditions in 10 CFR 50.55a(b), "Use and conditions on the use of standards."
ASME OM Code, 2012 Edition, paragraph ISTA-1100, Scope, states:
Section 1ST establishes the requirements for preservice and inservice testing and examination of certain components to assess their operational readiness in light-water reactor nuclear power plants. It identifies the components subject to test or examination, responsibilities, methods, intervals, parameters to be measured and evaluated, criteria for evaluating the results, corrective action, personnel qualification, and record keeping.
ASME OM Code, 2012 Edition, ISTA-1100, provides instructions for the assurance of operational readiness of certain components, such as valves, through periodic performance testing. Operational readiness is a component's ability to perform its function as described by plant design and TSs. ASME OM Code, 2012 Edition, also contains instructions for resolving issues identified via testing, and the corrective action provisions detail the role of analysis and maintenance in restoring components to meeting design requirements. ASME OM Code serves a similar function to 10 CFR 50, Appendix J. ASME OM Code components are assessed on a periodic basis to assure performance capability. When performance criteria are not met, analysis is performed to verify operational readiness or maintenance is performed to restore performance and verified with follow-up testing. These requirements ensure licensees are effectively protecting the public health and safety by maintaining plant equipment to the specifications established by the plant design and TSs.
The ASME OM Code, 2012 Edition allows performing supplemental position verification at frequencies longer than two years for MOVs which are subject to testing in accordance with Mandatory Appendix Ill. 10 CFR 50.55a(b )(3)(xi), requires supplemental position verification for MOVs at the lnservice Test (1ST) frequency. In accordance with Mandatory Appendix Ill, the maximum test frequency shall be set such that the MOV functional margin does not decrease below the acceptance criteria and does not exceed 1O years. The ASME OM Code, Mandatory Appendix Ill and 10 CFR 50, Appendix J both use performance-based approaches to establish test intervals. For MPS3, 10 CFR 50, Appendix J allows a test'frequency of up to 75 months or a maximum of four 18-month operating cycles.
For the valves in Table 1, performing the supplemental position verification on an interval consistent with 10 CFR 50, Appendix J aligns with the frequency of an NRG-endorsed testing program. Therefore, the past performance of MPS3 valves in Table 1, coupled with the utilization of the robust, performance-based, program requirements from 10 CFR 50, Appendix J, Option B, justify that the proposed alternative provides an acceptable level of quality and safety.
Serial No.21-082 Docket No. 50-423 Attachment, Page 7 of 7
- 6) Duration of Proposed Alternative This proposed alternative is requested for the remainder of the MPS3 fourth 10-year 1ST interval, which began on December 2, 2018 and will end on December 1, 2028. .
- 7) Precedents Similar requests have been approved for Fermi, Unit 2 (ADAMS Accession No. ML173548002), Beaver Valley Power Station, Unit 2 (Request VR3, ADAMS Accession No. ML17255A526), and Palo Verde Nuclear Generating Station, Units 1, 2, and 3 (ADAMS Accession No. ML19310F679).
- 8) References
- 1. ASME OM-2012, "Operation and Maintenance of Nuclear Power Plants," April 8, 2013
- 2. 10 CFR 50, Appendix J, "Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors"
- 3. NEI 94-01, Revision 3A, "Industry Guideline for Implementing Performance-Based Option of 10 CFR Part 50, Appendix J," dated July 2012
- 4. Regulatory Guide 1.163, "Performance-Based Containment Leak-Test Program,"
September 1995
- 5. USNRC, "Millstone Power Station Unit No. 3 - Issuance of Amendment No. 276 Regarding Revision to the Integrated Leak Rate Type A and Type C Test Intervals (EPID L-2019-LLA-0165)," dated July 16, 2020 (ADAMS Accession No. ML20161A000)