ML20275A343

Verbal Authorization for Proposed Alternative (RR 5-8) Reactor Vessel Closure Head Penetration Repairs

ML20275A343
Person / Time
Site:	Palisades
Issue date:	10/01/2020
From:	Booma Venkataraman Plant Licensing Branch III
To:	Miksa J Entergy Nuclear Operations
Venkataraman B
References
EPID: L-2020-LLR-0128
Download: ML20275A343 (3)

Text

From: Venkataraman, Booma To: "MIKSA, JAMES P" Cc: Salgado, Nancy; Mitchell, Matthew; Cumblidge, Stephen; Collins, Jay

Subject:

Palisades: Verbal Authorization for Proposed Alternative (RR 5-8) Re: Reactor Vessel Closure Head Penetration Repairs (EPID: L-2020-LLR-0128)

Date: Thursday, October 01, 2020 2:10:00 PM Attachments: Palisades Verbal Authorization_ RR 5-8_ EPID L-2020-LLR-0128 10012020.pdf By telephone conversation on October 1, 2020, the U.S. Nuclear Regulatory Commission (NRC) staff provided a verbal authorization to Entergy Nuclear Operations, Inc. (Entergy, the licensee) for a proposed alternative to certain requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section III, Section XI, and Code Case N-638-7 related to the repair of degraded reactor vessel closure head penetration numbers 17 and 34 at Palisades Nuclear Plant (Palisades). The licensee submitted Relief Request No. RR 5-8, for the proposed alternative, during the current fall 2020 refueling outage, to support the repair alternative for Palisades next operating cycle, which will be less than 20 months.

The NRC staffs evaluation and verbal authorization is repeated in the attachment to this e-mail.

The following NRC and licensee personnel participated in the conference call:

NRC Nancy Salgado - Chief, Plant Licensing Branch 3 (LPL3)

Matthew Mitchell - Chief, Piping and Head Penetrations Branch (NPHP)

Stephen Cumblidge - Materials Engineer (NPHP)

Booma Venkataraman - Project Manager (LPL3)

Entergy Jim Miksa - Palisades, Regulatory Assurance Engineer Otto Gustafson - Palisades, Regulatory Assurance and Performance Improvement Director Jeff Hardy - Palisades, Regulatory Assurance Manager Barb Dotson - Palisades, Regulatory Assurance Specialist Kevin OConnor - Palisades, Engineering Director Joe Jerz - Palisades, Engineering Manager Stephanie Weimer - Palisades, Engineering Supervisor Phil Couture - Entergy Fleet Regulatory Assurance Manager Howard Mahan - Entergy Fleet Regulatory Assurance Engineer Let me know, if you have any questions.

Sincerely, Booma Booma Venkataraman Project Manager, NRR/DORL/LPL3 Office of Nuclear Reactor Regulation Booma.Venkataraman@nrc.gov 301.415.2934

VERBAL AUTHORIZATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION FOR RELIEF REQUEST NUMBER RR 5-8 ALTERNATE REPAIR OF REACTOR VESSEL CLOSURE HEAD PENETRATION NOZZLES ENTERGY NUCLEAR OPERATIONS, INC PALISADES NUCLEAR PLANT DOCKET NO. 50-255 OCTOBER 1, 2020 Technical Evaluation read by Matthew Mitchell, Chief of the Piping and Head Penetrations Branch, Office of Nuclear Reactor Regulation By letter to the U.S. Nuclear Regulatory Commission (NRC) dated September 23, 2020, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML20267A386), as supplemented by letter dated September 28, 2020 (ADAMS Accession No. ML20272A162), Entergy Nuclear Operations, Inc. (the licensee) proposed an alternative to certain requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section III, Section XI, and Code Case N-638-7 related to the repair of degraded reactor vessel closure head (RVCH) penetration numbers 17 and 34 at Palisades Nuclear Plant (Palisades). The licensee submitted Relief Request No. RR 5-8, for the proposed alternative, during the current fall 2020 refueling outage, to support the repair alternative for Palisades next operating cycle, which will be less than 20 months.

The licensee requested authorization for this alternative in accordance with the requirements of Title 10 of the Code of Federal Regulations (10 CFR), Part 50, Section 50.55a(z)(1), on the basis that the proposed alternative repair will provide an acceptable level of quality and safety.

In its September 23, 2020 request, the licensee proposed to use a half-nozzle repair method with inside diameter temper bead welding to repair and restore the pressure boundary of the degraded nozzle penetrations. To support its repair option, the licensee proposed an alternative to the following:

1) the in-process examination requirements of ASME Code,Section III;

2) the flaw acceptance criteria of ASME Code,Section XI; and,

3) certain materials requirements of ASME Code Case N-638-7.

The specific details regarding the above are provided in the licensees letter dated September 23, 2020. Given the duration of the proposed alternative, the licensee indicated that it will also not perform rotary peening on the inner diameter of the repaired nozzles.

The licensee performed the following analyses in support of the proposed alternative:

(1) the evaluation of a postulated flaw in the J-groove weld that propagates into the reactor vessel head; (2) the evaluation of a postulated flaw at the triple point; (3) the evaluation of loose parts from the degraded J-groove weld; and (4) a corrosion evaluation of the bore of the reactor vessel head penetration which will be exposed to primary reactor coolant as a result of the repair.

Collectively these licensee evaluations address the safety concerns which could be raised by the licensees proposed alternatives to ASME Code requirements. Further, the licensees evaluations provide reasonable assurance that the proposed repair will provide adequate protection of public health and safety.

The NRC staff performed independent flaw evaluations in the roll-expanded region and near the repair weld, has confirmed the results of the analyses submitted by the licensee, and has determined that the licensees proposed repair method supports 20 months of operation.

Reasonable assurance of the material properties is provided by the testing requirements in ASME Code Case N-638-7. If any leakage does occur during operation the licensee has leakage monitoring and radiation air monitoring that would detect significant leakage through the repaired nozzles. The NRC staff finds the licensees proposed alternative and supporting analyses to be acceptable for the proposed 20-month duration.

The NRC staff determines that the proposed alternative, under RR 5-8, will provide reasonable assurance that the structural integrity of the repaired reactor vessel closure head and repaired nozzle numbers 17 and 34 will be maintained for the next operating cycle, not to exceed 20 months of full power operation, or May 31, 2022 when Palisades will permanently cease power operations.

NRC Staff Conclusion read by Nancy Salgado, Branch Chief, Plant Licensing Branch III, Office of Nuclear Reactor Regulation As Chief of Plant Licensing Branch III, I concur with the Piping and Head Penetration Branch's determinations.

The NRC staff concludes that the proposed alternative, under Relief Request No. RR 5-8 will provide an acceptable level of quality and safety for the repaired reactor vessel closure head nozzle numbers 17 and 34. Accordingly, the NRC staff concludes that the licensee has adequately addressed all of the regulatory requirements set forth in 10 CFR 50.55a(z)(1) and is in compliance with the requirements of the ASME Code,Section III, Section XI, ASME Code Case N-638-7, as conditioned in Regulatory Guide 1.147, and ASME Code Case N-729-4, as conditioned by 10 CFR 50.55a(g)(6)(ii)(D). Therefore, as of October 1, 2020, the NRC authorizes the use of Relief Request No. RR 5-8 for the alternate repair of the reactor vessel closure head nozzle numbers 17 and 34 for next fuel cycle, not to exceed 20 months of full power operation, or May 31, 2022 when Palisades will permanently cease power operations.

All other requirements of ASME Code,Section III, Section XI, and 10 CFR 50.55a(g)(6)(ii)(D) for which relief was not specifically requested and authorized by the NRC staff remain applicable, including the third-party review by the Authorized Nuclear lnservice Inspector.

This verbal authorization does not preclude the NRC staff from asking additional questions and clarifications regarding Relief Request No. RR 5-8 while preparing the subsequent written safety evaluation.