ML12135A040
| ML12135A040 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 05/08/2012 |
| From: | Price J Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 12-326 | |
| Download: ML12135A040 (87) | |
Text
VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 May 8, 2012 U.S. Nuclear Regulatory Commission Serial No.12-326 Attention: Document Control Desk NLOS/ETS RO One White Flint North Docket No.
50-338 11555 Rockville Pike License No. NPF-4 Rockville, MD 20852-2738 VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION)
NORTH ANNA POWER STATION UNIT I - RELIEF REQUEST NI-14-CMP-001 NONDESTRUCTIVE EXAMINATION RESULTS FOR THE STEAM GENERATOR HOT LEG INLET NOZZLES FULL STRUCTURAL WELD OVERLAY CONFIGURATION By letter dated March 30, 2011 (Serial No.11-120), Dominion requested NRC approval for a proposed alternative to certain ASME Code Section XI -
2004 Edition requirements associated with the Steam Generator hot leg nozzle repairs.
The proposed alternative permitted the application of full structural weld overlays (FSWOLs) to mitigate the potential for primary water stress corrosion cracking (PWSCC) susceptibility at North Anna Unit 1. By letter dated March 13, 2012, the NRC approved Relief Request NI-14-CMP-001.
Dominion installed FSWOLs on the Steam Generator hot leg nozzle dissimilar metal welds (DMWs) during the North Anna Unit 1 spring 2012 refueling outage.
As a condition of the alternative, Dominion committed to provide a listing of indications detected and the disposition of all indications using the standards of ASME Code Section XI, IWB-3514-2 and/or IWB-3514-3 criteria and, if possible, the type and nature of the indications. The attachment to this letter provides a summary of the indications and the disposition of each indication for the three Steam Generator hot leg weld overlays. In addition, examination results for the seal weld on the B Steam generator hot leg are included in the attachment.
As a result of the ultrasonic (UT) examinations there were no repairs required to the base metal, DM weld, or butter for the A and C Steam Generator hot leg nozzles.
However, prior to deposition of the FSWOL for the B hot leg nozzle, unacceptable indications were identified in the alloy 82/182 DM weld and butter. The unacceptable indications present at the surface where the overlay was to be installed were partially excavated, seal welded, and then the FSWOL was completed as a repair in accordance with the approved relief request. The completed FSWOLs for all three hot leg nozzles had no rejectable indications.
A04t7
Serial No.12-326 Docket No. 50-338 Page 2 of 2 If you have any questions regarding this submittal, please contact Mr. Thomas Shaub at (804) 273-2763.
Sincerely, J.A ice Vic ePr.ident - Nuclear Engineering
Attachment:
NDE Results for Steam Generator Hot Leg Nozzle FSWOLs Commitments made in this letter: None cc:
U.S. Nuclear Regulatory Commission Region II Marquis One Tower 245 Peachtree Center Ave., NE, Suite 1200 Atlanta, Georgia 30303-1257 Mr. J. E. Reasor, Jr. (without attachment)
Old Dominion Electric Cooperative Innsbrook Corporate Center 4201 Dominion Blvd.
Suite 300 Glen Allen, Virginia 23060 NRC Senior Resident Inspector North Anna Power Station Dr. V. Sreenivas NRC Project Manager U. S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop 08 G-9A Rockville, Maryland 20852 Ms. K. R. Cotton NRC Project Manager U. S. Nuclear Regulatory Commission One White Flint North 1 1555 Rockville Pike Mail Stop 08 G-9A Rockville, Maryland 20852 Mr. M. M. Grace Authorized Nuclear Insurance Inspector North Anna Power Station