NL-20-0941, Notification of Deviation from Pressurized Water Reactor Owner'S Group Topical Report WCAP-17451-P, Revision 2

Notification of Deviation from Pressurized Water Reactor Owner'S Group Topical Report WCAP-17451-P, Revision 2

ML20247J554
Person / Time
Site:	Vogtle
Issue date:	09/02/2020
From:	Gayheart C Southern Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NL-20-0941, WCAP-17451-P, Rev 2
Download: ML20247J554 (2)

Text

Cheryl A. Gayheart 3535 Colonnade Parkway Regulatory Affairs Director Birmingham, AL 35243 205 992 5316 cagayhea@southernco.com September 2, 2020 Docket No. 50-425 NL-20-0941 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Vogtle Electric Generating Plant, Unit 2 Notification of Deviation from Pressurized Water Reactor Owners Group Topical Report WCAP-17451-P, Revision 2 Ladies and Gentlemen, Southern Nuclear Operating Company (SNC) is providing notification that Vogtle Electric Generating Plant, Unit 2 (Vogtle-2), has processed a deviation from a Nuclear Energy Institute (NEI) 03-08, "Guideline for the Management of Materials Issues," Revision 3, "Needed" work product element in Pressurized Water Reactor Owners Group (PWROG) report WCAP-17451-P, Revision 2, "Reactor Internals Guide Tube Wear - Westinghouse Domestic Fleet - Operational Projections," with appropriate justification and documentation.

Control Rod Guide Tube (CRGT) guide card wear measurement is a "Needed" requirement specified in WCAP-17451-P, Revision 2. It contains examination timing and scope requirements consistent with the Electric Power Research Institute Materials Reliability Program (MRP) interim guidance letter MRP 2018-007 related to CRGT guide card wear which is referred to in MRP-227 Revision 1-A. Vogtle-2 has elected to delay wear measurement of its CRGT guide cards for one additional Refueling Outage (from V2R21 in fall 2020 to V2R22 in spring 2022) which will exceed the maximum 29 effective full power year (EFPY) requirement contained in both documents.

NEI 03-08 allows deviation from "Needed" elements with the appropriate justification and documentation. The deviation was approved by appropriate levels of SNC management. SNC opted to deviate from the industry guidance schedule due to reactor coolant pump (RCP) vibration issues developing during operating cycle 21. This prompted a decision to begin V2R21 approximately one month early and plan RCP removal on an emergent basis. The RCP removal requires the plant to be at mid-loop level while the pump is removed. This scope introduces a new outage window that precludes invessel activities that require the cavity to be flooded. In addition, the RCP work introduces an additional level of risk associated with coordination and execution of the large scope of activities, as well as schedule uncertainty with the RCP1 work and added personnel dose for all work in containment. CRGT guide card wear measurements would further add to this. Deferring the guide card wear inspections to V2R22 (Spring 2022) facilitates a much more favorable outage work risk profile and more certainty of schedule adherence.

The specific deviation from industry guidance due to the Vogtle-2 deferral is exceeding the limit of 29 EFPY set forth in WCAP-17451-P, Revision 2, and in MRP interim guidance letter 2018-007.

The deferral of guide card wear measurements at Vogtle-2 is to V2R22 (Spring 2022) and projects

U. S. Nuclear Regulatory Commission NL-20-0941 Page 2 to an operating time of approximately 29.8 EFPY. Thus, Vogtle-2 would exceed the upper EFPY limit by 0.8 EFPY. A comparison of the operating time between Vogtle Electric Generating Plant, Unit 1 (Vogtle-1), which accumulated 29.6 EFPY when measurements were completed in March 2020, and Vogtle-2 shows that Vogtle-2 would project to accumulate approximately 0.2 EFPY or

<1% due to the deferral. Based on the evaluation of the Vogtle-1 wear being comparable to Vogtle-2, there is more than adequate margin to justify the one-cycle deferral.

This notification is provided for information only. No approval or action is expected.

This letter contains no NRC commitments. If you have any questions, please contact Jamie Coleman at 205.992.6611.

Respectfully, Cheryl A. Gayheart Regulatory Affairs Director CAG/dsp/sm cc: Regional Administrator NRR Project Manager - Vogtle 1 & 2 Senior Resident Inspector - Vogtle 1 & 2 RType: CVC7000