ML15134A326
| ML15134A326 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 05/18/2015 |
| From: | Martin R Plant Licensing Branch II |
| To: | Pierce C Southern Nuclear Operating Co |
| Martin R | |
| References | |
| TAC MF4987 | |
| Download: ML15134A326 (3) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 May 18, 2015 Mr. C. R. Pierce Regulatory Affairs Director Southern Nuclear Operating Company, Inc.
Post Office Box 1295, Bin - 038 Birmingham, AL 35201-1295
SUBJECT:
VOGTLE ELECTRIC GENERATING PLANT, UNIT 1 - REGARDING THE 2014 STEAM GENERATOR TUBE INSPECTIONS (TAC NO. MF4987)
Dear Mr. Pierce:
By letter dated October 3, 2014 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML14276A430), Southern Nuclear Operating Company (the licensee) submitted information summarizing the results of the spring 2014 steam generator tube inspections performed at Vogtle Electric Generating Plant, Unit 1. These inspections were performed during refueling outage 18. In a letter dated April 2, 2015 (ADAMS Accession No. ML15092A831 ), the licensee provided additional information concerning these inspections.
The U.S. Nuclear Regulatory Commission (NRC) staff has completed its review of the reports and concludes that the licensee provided the information required by their technical specifications and that no additional follow-up is required at this time. The NRC staff's review of the reports is enclosed.
Docket No. 50-424
Enclosure:
Review of Report cc w/encl: Distribution via Listserv Sincerely,
/f?;J J~v r-efob M~rtin, Senior Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF NUCLEAR REACTOR REGULATION REVIEW OF THE SPRING 2014 STEAM GENERATOR TUBE INSPECTION REPORT VOGTLE ELECTRIC GENERATING PLANT. UNIT 1 DOCKET NO. 50-424 By letter dated October 3, 2014 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML14276A430), Southern Nuclear Operating Company (the licensee) submitted information summarizing the results of the spring 2014 steam generator (SG) tube inspections performed at Vogtle Electric Generating Plant, Unit 1. These inspections were performed during refueling outage 18. In a letter dated April 2, 2015 (ADAMS Accession No. ML15092A831), the licensee provided additional information concerning these inspections.
Vogtle Electric Generating Plant, Unit 1, has four Westinghouse Model F SGs, each of which contains 5,626 U-bend thermally treated Alloy 600 tubes. Each tube has a nominal outside diameter of 0.688 inches and a nominal wall thickness of 0.040 inches. During SG fabrication, the tubes were hydraulically expanded, at both ends, over the full depth of the tubesheet. The vertical sections of the tubes are supported by Type 405 stainless steel support plates, which have broached quatrefoil holes. The U-bend sections of the tubes are supported by Type 405 stainless steel anti-vibration bars.
The licensee provided the scope, extent, methods, and results of their SG tube inspections in the documents referenced above. In addition, the licensee described corrective actions (i.e.,
tube plugging) taken in response to the inspection findings. After reviewing the information provided by the licensee, the U.S. Nuclear Regulatory Commission (NRC) staff has the following comments/observations:
Cracking was identified at the expansion transition region on the hot-leg side of SG 4 and in a bulge in the tubesheet on the hot-leg side of SG 4.
Based on a review of the information provided, the NRC staff concludes that the licensee provided the information required by their technical specifications. In addition, the NRC staff concludes that there are no technical issues that warrant follow-up action at this time since the inspections appear to be consistent with the objective of detecting potential tube degradation and the inspection results appear to be consistent with industry operating experience at similarly designed and operated units.
Principal Contributor: A. Johnson Date: May 18, 2015 Enclosure
- By memo dated May 6, 2015 OFFICE DORL/LPL2-1/PM DORL/LPL2-1/LA NRR/DE/ESGB*
DORL/LPL2-1/BC DORL/LPL2-1 /PM NAME BMartin SFigueroa GKulesa RPascarelli BMartin DATE 05/15/15 05/15/15 05/06/15 05/18/15 05/18/15