ML24226A365
| ML24226A365 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 05/13/2024 |
| From: | Hipolito Gonzalez Plant Licensing Branch 1 |
| To: | Vistra Operations Company |
| Sreenivas, V | |
| References | |
| EPID L-2024-LLR-0032 | |
| Download: ML24226A365 (5) | |
Text
BEAVER VALLEY POWER STATION, UNIT NO. 1 - APPROVAL OF REQUEST FOR ALTERNATIVE FROM CERTAIN REQUIREMENTS OF THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS BOILER AND PRESSURE VESSEL CODE (EPID L-2024-LLR-0032)
LICENSEE INFORMATION Licensee:
Vistra Operations Company LLC Licensee Address:
P.O. Box 4 200 State Route 3016 Shippingport, PA 15077 Plant Name and Unit:
Beaver Valley Power Station, Unit No. 1 Docket No.:
50-334 APPLICATION INFORMATION Submittal Date: 5/13/2024 Submittal Agencywide Documents Access and Management System (ADAMS) Accession No.: ML24134A204 Supplement Date: NA Supplement ADAMS Accession No.: NA Licensee Proposed Alternative No. or Identifier: 1-TYP-5-RRP-1 Applicable Regulation: Title 10 of the Code of Federal Regulations (10 CFR),
Section 50.55a(z)(1)
Applicable Code Requirements:
ASME Code,Section XI, IWA-4422.2.2, Defect Removal Followed by Welding or Brazing, (e) Examination following welding or brazing shall be in accordance with IWA-4520.
ASME Code,Section XI, IWA-4520, Examination, (a) Welding or brazing areas and welded joints made for fabrication or installation of items by a Repair/Replacement Organization shall be examined in accordance with the Construction Code identified in the Repair/Replacement Plan.
ASME Code,Section III, NC-2539.4, Examination of Repair Welds Each repair weld shall be examined by the magnetic particle method (NC-2545) or by the liquid penetrant method (NC-2546). In addition, when the depth of the repair cavity exceeds the lesser of 3/8 in. (10 mm) or 10% of the section thickness, the repair weld shall be radiographed in accordance with and to the applicable acceptance standards of NC-5320. The image quality indicator (IQI) shall be based upon the section thickness of the repaired area.
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Applicable Code Edition and Addenda===
The American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (ASME Code),Section XI, 2013 Edition.
10 CFR 50.55a(b)(2)(xx)(B), System Leakage Tests: Second provision Brief Description of the Proposed Alternative:
The licensee proposed to perform a progressive surface exam using magnetic particle testing (MT) and ultrasonic thickness measurements in lieu of the volumetric radiographic testing (RT) examination required by ASME Code,Section III, NC-2539.4.
The first and subsequent weld layers will be examined using MT. The examinations will use the acceptance criteria of ASME Code,Section III, NC-5340, Magnetic Particle Acceptance Standards. The final surface will be flattened and blended into the surrounding base material and shall receive a final MT and ultrasonic thickness examination.
For additional details on the licensees submittal, please refer to the document located at the ADAMS Accession No. identified above.
REGULATORY EVALUATION Regulatory Basis: 10 CFR 50.55a(z)(1)
Adherence to Section XI of the ASME Code is mandated by 10 CFR 50.55a(g)(4), which states, in part, that ASME Code Class 1, 2, and 3 components will meet the requirements, except the design and access provisions and the pre-service examination requirements, set forth in the ASME Code,Section XI.
Paragraph 10 CFR 50.55a(z) states, in part, that alternatives to the requirements of 10 CFR 50.55a(b)-(h) may be used, when authorized by the Director, Office of Nuclear Reactor Regulation, if (1) the proposed alternatives would provide an acceptable level of quality and safety or (2) compliance with the specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.
The licensee has submitted this request on the basis that a proposed alternative would provide an acceptable level of quality and safety.
TECHNICAL EVALUATION The licensee requested authorization for this alternative in accordance with the requirements of 10 CFR Part 50, Section 50.55a(z)(1) on the basis that compliance with the specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety. Verbal authorization for proposed alternative 1-TYP-5-RRP-1 was given on May 14, 2024 (ADAMS Accession No. ML24136A130). This safety evaluation documents the technical basis for the U.S. Nuclear Regulatory Commissions (NRC) verbal authorization.
During refueling and maintenance outage 1R29, a 30 drops-per-minute leak was identified on the river water outlet piping for 1RS-E-1A between metal expansion joint MEJ-1RW-1 and containment penetration X-83. The through-wall flaw was later confirmed using ultrasonic testing (UT).
The location of the flaw is directly adjacent to the containment wall and associated liner at the interface of the containment penetration and liner. The through-wall flaw stops at the boundary of the test channel; the thinned material continues into the test channel. The location of the flaw and the thinned area and the geometry of the piping near the thinned area makes conventional RT difficult.
ASME Code,Section XI, IWA-4520, Examination requires RT examinations to be performed.
The licensee is proposing to perform a progressive surface exam using MT in lieu of the volumetric RT examination required by ASME Code,Section III, NC-2539.4. Base metal weld repairs will be performed using Gas-Tungsten Arc Welding with ER70S-2 filler material. The first and subsequent weld layers will be progressively examined via MT to ensure weld quality. The repair will restore the pipe wall thickness to approximately 0.25 inches, 0.204 inches more than the 0.046-inch allowed minimum wall thickness. The finished repair will be examined using MT and a UT thickness examination.
After the repair is completed, the section of piping will be pressurized with air to 44.5 psi in accordance with a 10 CFR Part 50, Appendix J Type B testing technique to find possible leaks.
A river water system alignment similar to design basis accident scenarios will also be used to perform an in-service leak test.
The River Water Outlet Piping 1RS-E-1A is a low-pressure pipe with a design pressure of 85 pounds per square inch gauge (psig) and an allowed minimum wall thickness of 0.046 inches. While successive MT is not as rigorous as RT testing, the repair will restore the wall thickness to approximately 0.25 inches, which provides a significant margin. The degradation mechanism is general corrosion, so any possible small additional weld flaws left in the weld would not significantly affect the rate of wall thinning. The final repair will be tested using UT to confirm the thickness of the repair. The air and water pressure testing that will be performed after the repair will determine if the repair is leak tight. The combination of these factors provides reasonable assurance of adequate safety for the repair.
Based on these considerations, the NRC staff has determined that complying with the alternative requirements described in the licensees request referenced above would result in an acceptable level of quality and safety.
CONCLUSION The U.S. Nuclear Regulatory Commission staff has determined that the proposed alternative in the licensees request referenced above would provide an acceptable level of quality and safety.
The NRC staff concludes that the licensee has adequately addressed the regulatory requirements set forth in 10 CFR 50.55a(z)(1).
The NRC staff authorizes the use of proposed alternative 1-TYP-5-RRP-1 at Beaver Valley Power Station, Unit No. 1 for the repair of the river water outlet piping for 1RS-E-1A between metal expansion joint MEJ-1RW-1 and containment penetration X-83.
All other ASME Code,Section XI requirements for which an alternative was not specifically requested and approved in this proposed alternative remain applicable, including third-party review by the Authorized Nuclear Inservice Inspector.
Principal Contributors: Stephen Cumblidge, NRR Matt Burton, NRR Date: August 21, 2024 Hipólito González, Branch Chief Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation HIPOLITO GONZALEZ Digitally signed by HIPOLITO GONZALEZ Date: 2024.08.21 12:38:52 -04'00'
ML24226A365 OFFICE NRR/DORL/LPL1/PM NRR/DORL/LPL1/LA NRR/DNRL/NPHP/BC NAME VSreenivas KZelenock MMitchell DATE 08/12/2024 08/13/2024 08/06/2024 OFFICE NRR/DORL/LPL1/BC NAME HGonzález DATE 08/20/2024