ML21026A260
| ML21026A260 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 02/08/2021 |
| From: | Jennifer Dixon-Herrity Plant Licensing Branch IV |
| To: | |
| Wengert T J-NRR/DORL 301-415-4037 | |
| References | |
| EPID L-2020-LLR-0110 | |
| Download: ML21026A260 (4) | |
Text
ARKANSAS NUCLEAR ONE, UNIT 1 - AUTHORIZATION AND SAFETY EVALUATION FOR ALTERNATIVE REQUEST NO. ANO1-ISI-034 (EPID L-2020-LLR-0110)
LICENSEE INFORMATION Licensee: Entergy Operations, Inc.
Plant Name and Unit: Arkansas Nuclear One, Unit 1 Docket No(s).: 50-313 APPLICATION INFORMATION Submittal Date: August 11, 2020 Submittal Agencywide Documents Access and Management System (ADAMS) Accession No.: ML20227A112 Supplement Date: December 10, 2020 Supplement ADAMS Accession No.: ML20345A174 Applicable Inservice Inspection (ISI) Program Interval and Interval Start/End Dates: Fifth 10-year ISI interval, May 31, 2017, to May 30, 2027 Alternative Provision: The applicant requested an alternative under Title 10 of the Code of Federal Regulations (10 CFR), paragraph 50.55a(z)(1), Acceptable level of quality and safety, however, the U.S. Nuclear Regulatory Commission (NRC) staff review found that while the supporting technical basis addresses the structural integrity concern, it did not adequately address the basis for leak tightness through the period of the extended inspection frequency in order to be authorized under 10 CFR 50.55a(z)(1). However, in Section V, Conclusion, of the enclosure to the letter dated August 11, 2020, Entergy Operations, Inc. (the licensee) identified the regulatory requirements for another option for authorization of this request under the hardship provision of 10 CFR 50.55a(z)(2), Hardship without a compensating increase in quality and safety. In Section II, Request for Relief, of the enclosure to the letter dated August 11, 2020, and in the supplemental letter dated December 10, 2020, the licensee provided a hardship basis for the proposed alternative.
ISI Requirement: The regulation in 10 CFR 50.55a(g)(6)(ii)(F), Augmented ISI requirements:
Examination requirements for Class 1 piping and nozzle dissimilar-metal butt welds, requires American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code)
Case N-770-5, Inspection Item B-1, for the volumetric examination frequency requirement for the high pressure injection (HPI) Nozzle D dissimilar metal weld at Arkansas Nuclear One, Unit 1 (ANO-1).
Applicable Code Edition and Addenda: ASME Code,Section XI 2007 Edition through 2008 Addenda.
Brief Description of the Proposed Alternative: The licensee requested a one-time extension of the volumetric examination frequency for the ANO-1 HPI nozzle D dissimilar metal weld.
The extension request is from the required frequency of not to exceed seven years to a proposed nominal frequency of 7.5 calendar years.
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 the level of quality and safety of the licensees proposed alternative that the examinations of the ANO-1 HPI nozzle D dissimilar metal weld should be delayed for one cycle of operation from a required frequency of every 7 years to allow a one-time extension to 7.5 years. The licensee provided a supporting basis though a flaw analysis, prior volumetric and visual examination results, and defense-in-depth actions including leakage monitoring. The NRC staff reviewed each of these factors in evaluating the level of quality and safety in the licensees proposed alternative. The NRC staff also performed an independent flaw analysis to evaluate the structural integrity of the weld through the requested examination frequency extension to 7.5 years. The NRC staff analysis confirmed the licensees analysis conclusion that structural integrity of the weld would be maintained throughout the period requested.
The NRC staff also reviewed and evaluated the licensees request 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. The licensee provided a hardship basis associated with the estimated radiological dose and need for additional personnel during the COVID-19 virus pandemic that would be required to perform the single weld examination alone, rather than in combination with examinations for three similar welds during the following refueling outage. The licensee estimated that approximately 1.65 rem (roentgen equivalent man) would be saved in the spring outage by performing all four HPI nozzle dissimilar metal weld examinations at the same time during the following outage. The licensee explained that this one examination requires four contractors to complete, and that it is the only examination these individuals would perform. The NRC staff reviewed the licensees hardship basis and has found the COVID-19 virus pandemic to be a hardship for the additional workers, plant staff personnel, and the members of the public in the vicinity of the plant who could be exposed to additional risk of infection. Additionally, the NRC staff finds that the licensees estimated radiological dose identified by the licensee is consistent with other similar volumetric examinations in similar locations of the plant. Given the radiological dose and COVID-19 concerns, the NRC staff finds that the licensee meets the hardship requirement of 10 CFR 50.55a(z)(2).
Given the licensees identified hardship, the NRC staff finds that the licensee has provided an adequate technical basis to extend the volumetric examination of the subject weld. The NRC staff also finds that the defense-in-depth operational leakage monitoring provides reasonable assurance that the structural integrity of the subject weld will be maintained, and that complying with the current volumetric examination requirement would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.
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 subject component. 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 ANO1-ISI-034 at Arkansas Nuclear One, Unit 1, until the fall 2022 refueling outage (1R30).
All other ASME 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 Contributor: Jay Collins Date: February 8, 2021 Sincerely, Jennifer L. Digitally signed by Jennifer L. Dixon-Herrity Dixon-Herrity Date: 2021.02.08 13:47:11 -05'00' Jennifer Dixon-Herrity, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation cc: Listserv
ML21026A260 OFFICE NRR/DORL/LPL4/PM NRR/DORL/LPL4/LA NRR/DNRL/NPHP/BC NRR/DORL/LPL4/PM NAME TWengert PBlechman MMitchell JDixon-Herrity DATE 2/8/2021 2/8/2021 1/14/2021 2/8/2021