ML23249A184

Authorization and Safety Evaluation for Alternative Request No. 2-TYP-4-RV-06

ML23249A184
Person / Time
Site:	Beaver Valley
Issue date:	09/18/2023
From:	Hipolito Gonzalez Plant Licensing Branch 1
To:	Blair B Energy Harbor Nuclear Corp
Goetz S
References
EPID L-2023-LLR-0021
Download: ML23249A184 (5)

Text

September 18, 2023

BEAVER VALLEY POWER STATION, UNIT NO. 2

AUTHORIZATION AND SAFETY EVALUATION FOR

ALTERNATIVE REQUEST NO. 2-TYP-4-RV-06

(EPID L-2023-LLR-0021)

LICENSEE INFORMATION

Recipients Name and Address :

Mr. Barry N. Blair Site Vice President Energy Harbor Nuclear Corp.

Beaver Valley Power Station Mail Stop P-BV-SSEB P.O. Box 4, Route 168 Shippingport, PA 15077-0004

Licensee: Energy Harbor Nuclear Corp.

Plant Name and Unit: Beaver Valley, Unit 2

Docket No.: 50-412

APPLICATION INFORMATION

Submittal Date: April 28, 2023

Submittal Agencywide Documents Access and Management System (ADAMS) Accession No.: ML23118A381

Supplement Date: May 5, 2023

Supplement ADAMS Accession No.: ML23125A290

Applicable Inservice Inspection (ISI) Interval and Interval Start/End Dates: The Fourth 10-year ISI interval at Beaver Valley Power Station, Unit 2, (BVPS-2) started on August 29, 2018, and is scheduled to end on August 28, 2028.

Alternative Provision: The applicant requested an alternative under Title 10 of the Code of Federal Regulations (10 CFR), paragraph 50.55a(z)(2), Hardship without a compensating increase in quality and safety.

ISI Requirement: Energy Harbor Nuclear Corp. (licensee) conducts inspections of BVPS-2 reactor vessel head (RVH) in accordance with the American Society of American Engineers

(ASME) Code Case N-729-6, Alternative Examination Requirements for PWR [pressurized-water reactor] Reactor Vessel Upper Heads With Nozzles Having Pressure-Retaining Partial-Penetration Welds, with conditions specified in 10 CFR 50.55a(g)(6)(ii)(D), Augmented ISI requirements: Reactor vessel head inspections.

Applicable Code Edition and Addenda: The applicable code of record for inservice inspection and repair/replacement program at BVPS-2 is ASME Boiler and Pressure Vessel Code (ASME Code),Section XI, 2013 Edition with no Addenda. The construction code for BVPS-2 is ASME Code Section III, 1971 Edition, 1973 Winter Addenda and the BVPS-2 reactor vessel construction code is ASME Section III, 1971 Edition, Summer 1972 Addenda.

Brief Description of the Proposed Alternative: During the spring 2023 refueling outage at BVPS-2, the licensee submitted a proposed alternative, 2-TYP-4-RV-06, for U.S. Nuclear Regulatory Commission (NRC) review and approval to support repair of two unacceptable flaw indications in the RVH vent penetration tube material and associated partial penetration weld at BVPS-2. The licensee stated that its repair will be in accordance with ASME Code,Section XI, IWA-4311, Material, Design or Configuration Changes, and ASME Code Case N-638-10, Similar and Dissimilar Metal Welding Using Ambient Temperature Machine GTAW [Gas Tungsten Arc Weld] Temper Bead Technique, with two specific exceptions to N-638-10 to eliminate the 48-hour hold time for final examination after the completion of temper bead welding, and to allow use of progressive liquid penetrant tests in lieu of volumetric examination.

Specifically, pursuant to 10 CFR 50.55a(z)(2), the licensee submitted the proposed alternative 2-TYP-4-RV-06 on the basis that complying with the specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.

The licensee requested approval of this proposed alternative until the RVH is replaced.

The NRC staff verbally approved proposed alternative 2-TYP-4-RV-06 on May 8, 2023, as documented by email dated May 9, 2023 (M L23129A312). This document provides the NRC staffs formal safety evaluation.

For additional details on the licensees request, please refer to the documents located at the ADAMS Accession Nos. identified above.

STAFF EVALUATION

The NRC staff reviewed and evaluated the licen sees request on the basis of 10 CFR 50.55a(z)(2), such that 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 stated that this repair is located in a high dose area and explained the hardship associated with this requirement was due to the limited geometry of the repair cavity. As such, meaningful volumetric examination results could not be obtained and alternative methods, such as eddy current examination, were not readily available. The NRC staff finds the licensees assessment of high radiological dose area and limited geometry meets the hardship requirement of 10 CFR 50.55a(z)(2).

The NRC staff reviewed the level of quality and safety of the licensees proposed alternative.

The licensees proposed repair includes removal of defect, verification of defect removal with surface examination, applying an intermediate weld buffer layer on cladding on the outer parameter of the weld excavation to provide is olation from contaminants in the cladding from affecting weld quality, followed by temper bead weld repair of the excavation with progressive surface examination of first three layers and each 3/16-inch weld deposit after that, followed by a final inspection. The NRC staff notes, as explained by the licensee, that the NRC has previously approved liquid penetrant examination in lieu of volumetric examination for temper

bead welding applications (ML23073A156). NRC-approved 2019 Edition of ASME Code,Section III allows progressive surface examinati on for temper bead repairs to partial penetration welds in lieu of volumetric examination if meaningful results cannot be obtained. Therefore, the NRC staff finds the licensees proposed alternative for progressive liquid penetrant tests in lieu of volumetric examination to be acceptable.

The NRC staff reviewed the licensees technical ju stification to eliminate the 48-hour hold time when using austenitic filler materials in the temper bead welding process for P-1 and P-3 ferritic materials. The licensee provided a white paper with detailed technical discussion, industrys operational experience, and list of similar repairs in support for justification of their technical bases for the request to eliminate the 48-hour hold for final nondestructive inspection. The NRC staff found the licensees basis for the proposed repair to be consistent with previous NRC approvals for the elimination of the 48-hour hold time (ML23090A130). The NRC staff is also unaware of any instances of hydrogen induced cracking, the primary concern for the 48-hour hold time, in the hundreds of welds that have been completed by the nuclear industry using various revisions of ASME Code Case N-638. Given this basis, the staff finds the elimination of the 48-hour hold time requirements of ASME Code Case N-638-10 to be acceptable.

The NRC staff reviewed the licensees proposed futu re examinations of the vent line penetration nozzle and associated weld. The NRC staff finds the licensees current understanding of the requirements under 10 CFR 50.55a(g)(6)(ii)(D) to perform a surface examination of the head vent penetration inside diameter combined with a surface examination of the attaching J-groove weld adequate. Given these examinations, including the bare metal visual examinations of the RVH each refueling outage, will be performed throughout the remaining life of the current RVH at BVPS-2, the NRC staff finds reasonable assurance of the continued monitoring of the structural integrity of this component for the remaining life of the current RVH at BVPS-2.

Based on the above evaluation, the NRC staff finds that the licensees proposed alternative 2-TYP-4-RV-06 provides reasonable assurance of structural integrity of the RVH vent line and associated weld for the duration of the proposed alternative. Given the hardship, the NRC staff finds that the complying with the current volumetric examination requirement and 48-hour hold time requirement to be in compliance with ASME Code Case N-638-10 would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety in accordance with 10 CFR 50.55a(z)(2).

CONCLUSION

The NRC staff has determined that complying with the specified requirements described in the licensees request referenced above would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.

The proposed alternative provides reasonable assurance of structural integrity of the RVH.

The NRC staff concludes that the licensee has adequately addressed the regulatory requirements set forth in 10 CFR 50.55a(z)(2).

The NRC staff authorizes the use of proposed alternative 2-TYP-4-RV-06 at BVPS-2 for the remaining life of the current RVH, until its replacement.

All other ASME BPV Code,Section XI, requirements for which an alternative was not specifically requested and authorized remain applicable, including third-party review by the Authorized Nuclear Inservice Inspector.

Principal Contributors: Omar Khan, Jay Collins

Date: September 18, 2023

Hipólito J. González, Chief Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

cc: Listserv

ML23249A184 OFFICE NRR/DORL/LPL1/PM NRR/DORL/LPL1/LA NRR/DNRL/NPHP/BC NAME VSreenivas KZeleznock (ABaxter for) SCumblidge DATE 09/05/2023 09/14/2023 09/05/2023 OFFICE NRR/DORL/LPL1/BC NAME HGonzález DATE 09/18/2023