ML17102A531
| ML17102A531 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 04/19/2017 |
| From: | Michael Orenak Plant Licensing Branch II |
| To: | Hutto J Southern Nuclear Operating Co |
| Orenak M, DORL/LPLII-1, 415-3229 | |
| References | |
| CAC MF8383 | |
| Download: ML17102A531 (4) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 April 19, 2017 Mr. James J. Hutto Regulatory Affairs Director Southern Nuclear Operating Company, Inc.
P. 0. Box 1295, Bin - 038 Birmingham, AL 35201-1295
SUBJECT:
VOGTLE ELECTRIC GENERATING PLANT, UNIT 2 - REVIEW OF THE FALL 2016 STEAM GENERATOR TUBE INSERVICE INSPECTION REPORT FOR REFUELING OUTAGE 18 (CAC NO. MF8383)
Dear Mr. Hutto:
By letter dated September 13, 2016 (Agencywide Documents Access and Management System Accession No. ML16257A297), Southern Nuclear Operating Company, Inc. (the licensee) submitted information summarizing the results of the spring 2016 steam generator tube inspections performed at Vogtle Electric Generating Plant (VEGP), Unit 2. These inspections were performed during Refueling Outage 18.
The U.S. Nuclear Regulatory Commission staff has completed its review of the submittal and concludes that the licensee provided the information required by the VEGP, Unit 2, technical specifications. No additional follow-up is required at this time. The results of the NRC staff's review and observations are enclosed.
If you have any questions, please contact me at 301-415-3229 or via email at Michael.Orenak@nrc.gov.
Docket No. 50-425
Enclosures:
Review of the Steam Generator Tube lnservice Inspection Report for Unit 2 Refueling Outage 18 cc w/encl: Distribution via ListServ Sincerely,
~~
Michael Orenak, Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
REVIEW OF THE RESULT OF THE 2016 STEAM GENERATOR TUBE INSPECTIONS PERFORMED DURING REFUELING OUTAGE 18 SOUTHERN NUCLEAR OPERATING COMPANY, INC.
VOGTLE ELECTRIC GENERATING PLANT. UNIT 2 DOCKET NO. 50-425 By letter dated September 13, 2016 (Agencywide Documents Access and Management System Accession No. ML16257A297), Southern Nuclear Operating Company, Inc. (the licensee) submitted information summarizing the results of the spring 2016 Steam Generator (SG) tube inspections performed at Vogtle Electric Generating Plant (VEGP), Unit 2. These inspections were performed during Refueling Outage (RFO) 18.
VEGP, Unit 2, 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 section of the tubes are supported by Type 405 stainless steel support plates with quatrefoil-shaped holes and the U-bend section of the tubes is supported by V-shaped, chrome-plated Alloy 600 anti-vibration bars.
The licensee provided the scope, extent, methods, and results of their SG tube inspections in the document 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:
A volumetric wear indication in SG 4 in the tube in row 57, column 68, was resolved from a Distorted Support Indication to a Distorted Support Signal by bobbin data history review in prior inspections. The licensee classified the indication as a volumetric flaw during RFO 18 based on a detailed history review of both bobbin and +Point probe data, which concluded that the indication has been present and unchanged since at least the RFO 9 inspection in 2002. The licensee stated that the tube remains inservice and will continue to be monitored as a volumetric indication during future inspections.
An indication in SG 1 in the tube in row 1, column 78, approximately 11 inches above the top of the tubesheet on the cold leg side was segregated into two separate volumetric indications. Prior inspections identified it as one indication and +Point probe data graphics show no change from prior inspections since at least 2008.
There were no crack-like indications identified at or near the top of the tubesheet during RFO 18.
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.
ML17102A531 OFFICE NRR/DORL/LPL2-1 /PM NRR/DORL/LPL2-1 /LA NRR/DE/ESGB/BC(A)*
NAME MOrenak KGoldstein AJohnson DATE 04/17/17 04/17/17 04/6/17 OFFICE NRR/DORL/LPL2-1 /PM NAME MOrenak DATE 4/19/17