ML18131A183
| ML18131A183 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 05/10/2018 |
| From: | Balwant Singal Plant Licensing Branch IV |
| To: | Muilenburg W Wolf Creek |
| References | |
| L-2018-LLR-0068 | |
| Download: ML18131A183 (4) | |
Text
1 NRR-DMPSPEm Resource From:
Singal, Balwant Sent:
Thursday, May 10, 2018 3:53 PM To:
Muilenburg William T (wimuile@WCNOC.com)
Cc:
Pascarelli, Robert; Ruffin, Steve; Render, Diane; Hafenstine Cynthia R
Subject:
Wolf Creek Relief Request I4R Verbal Authorization (EPID L-2018-LLR-0068)
Attachments:
Wolf Creek Verbal Auth I4R-06.docx By telephone call on May 10, 2018, the U.S. Nuclear regulatory Commission (NRC) staff provided verbal authorization to Wolf Creek Nuclear Operating Corporation (WCNOC, the licensee) for the subject relief request based on the attached explanation.
Participants:
NRC Steve Ruffin, Branch Chief (provided technical justification)
Robert Pascarelli, Branch Chief (provided authorization)
Diane Render, Materials Engineer Balwant Singal, Senior Project Manager James Drake, Region IV Isaac Anchondo, Region IV Jim Melfi, Region IV WCNOC Bill Muilenburg - Supervisor Licensing Nicole Good - Licensing David Giefer - Engineer Jeff Wilson - Engineering Supervisor Please let me know if you have any questions.
Thanks.
Balwant K. Singal Senior Project Manager (Diablo Canyon and Wolf Creek)
Nuclear Regulatory Commission Division of Operating Reactor Licensing Balwant.Singal@nrc.gov Tel: (301) 415-3016 Fax: (301) 415-1222
Hearing Identifier:
NRR_DMPS Email Number:
368 Mail Envelope Properties (Balwant.Singal@nrc.gov20180510155300)
Subject:
Wolf Creek Relief Request I4R Verbal Authorization (EPID L-2018-LLR-0068)
Sent Date:
5/10/2018 3:53:28 PM Received Date:
5/10/2018 3:53:00 PM From:
Singal, Balwant Created By:
Balwant.Singal@nrc.gov Recipients:
"Pascarelli, Robert" <Robert.Pascarelli@nrc.gov>
Tracking Status: None "Ruffin, Steve" <Steve.Ruffin@nrc.gov>
Tracking Status: None "Render, Diane" <Diane.Render@nrc.gov>
Tracking Status: None "Hafenstine Cynthia R" <cyhafen@WCNOC.com>
Tracking Status: None "Muilenburg William T (wimuile@WCNOC.com)" <wimuile@WCNOC.com>
Tracking Status: None Post Office:
Files Size Date & Time MESSAGE 971 5/10/2018 3:53:00 PM Wolf Creek Verbal Auth I4R-06.docx 22359 Options Priority:
Standard Return Notification:
No Reply Requested:
No Sensitivity:
Normal Expiration Date:
Recipients Received:
VERBAL AUTHORIZATION BY OFFICE OF NUCLEAR REACTOR REGULATION RELIEF REQUEST I4R-06 WOLF CREEK GENERATING STATION WOLF CREEK NUCLEAR OPERATING CORPORATION DOCKET NUMBER 50-482 May 10, 2018 Technical Evaluation read by Steve Ruffin, Chief of the Piping and Head Penetrations Branch, Office of Nuclear Reactor Regulation By letter dated May 2, 2018 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML18128A186), Wolf Creek Nuclear Operating Corporation (the licensee) submitted Relief Request I4R-06 for the alternate volumetric examination and leak path assessment of reactor vessel closure head (RVCH) nozzle Number 1 at the Wolf Creek Generating Station.
The licensee made this request in accordance with the requirements of 10 CFR 50.55a(z)(1), such that the combination of a volumetric examination and leak path assessment provides an acceptable level of quality and safety.
During Refueling Outage 22, the licensee could not perform an acceptable bare metal visual examination on RVCH Nozzle No. 1 required by Table 1, Item No. B4.10 of ASME Code Case N-729-4 because the annulus region of the nozzle was obscured by a foreign object. In lieu of performing an acceptable bare metal visual examination, the licensee proposed to perform a volumetric examination of essentially 100 percent of RVCH Nozzle No. 1 and a demonstrated volumetric leak path assessment of the nozzle penetration. Additionally, the licensee will clean the reactor vessel closure head nozzle penetration and perform a supplemental visual examination prior to returning to service in the current Refueling Outage No. 22.
The NRC staff finds that the volumetric examination of the nozzle and the demonstrated volumetric leak path are NRC approved inspection techniques in accordance with ASME Code Case N-729-4, and that together they provide reasonable assurance of detecting a leak from either the penetration nozzle or the associated attachment weld. The NRC staff found that the foreign object only obscured the licensees ability to verify that the penetration was not leaking, and did not prevent the licensee from verifying the general integrity of the low alloy steel head. Therefore, the NRC staff recognizes that the only concern for the missed inspection coverage was the ability to confirm no leakage through the penetration nozzle or weld. Therefore, to address the inspection limitation imposed by the foreign object at nozzle penetration number 1, the NRC staff finds that the use of the volumetric examination of the nozzle and demonstrated volumetric leak path assessment are adequate to provide reasonable assurance of leak tightness and structural integrity of the RVCH. As such, the NRC staff finds that the licensees proposed alternative provides an acceptable level of quality and safety.
Authorization read by Robert Pascarelli, Chief of the Plant Licensing Branch IV, Office of Nuclear Reactor Regulation As Chief of the Plant Licensing Branch IV, Office of Nuclear Reactor Regulation, I concur with the Piping and Head Penetrations Branchs determinations.
The NRC staff concludes that the proposed alternative provides reasonable assurance of structural integrity of one nozzle penetration and provides an acceptable level of quality and safety. 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 10 CFR 50.55a(g)(6)(ii)(D). Therefore, on May 10, 2018, the NRC staff authorizes the use of relief request I4R-06 at the Wolf Creek Generating Station during the current refueling outage 22 subject to the licensees proposed alternative that if an unacceptable indication by the leak path assessment or volumetric examination is identified, the licensee will revert to the requirements of ASME Code Case N-729-4 and 10 CFR 50.55a(g)(6)(ii)(D).
All other requirements of ASME Code,Section XI, for which relief was not specifically requested and authorized by the NRC staff remain applicable, including the third party review by the Authorized Nuclear In-service Inspector.
This verbal authorization does not preclude the NRC staff from asking additional clarification questions regarding Relief Request I4R-06, while preparing the subsequent written safety evaluation.