ML071340129
| ML071340129 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 06/06/2007 |
| From: | Catherine Haney Plant Licensing Branch III-2 |
| To: | Korsnick M Ginna |
| Pickett D, NRR/DORL, 415-1364 | |
| References | |
| TAC MD4154 | |
| Download: ML071340129 (4) | |
Text
June 6, 2007 Mrs. Mary G. Korsnick Vice President R.E. Ginna Nuclear Power Plant R.E. Ginna Nuclear Power Plant, LLC 1503 Lake Road Ontario, NY 14519
SUBJECT:
R.E. GINNA NUCLEAR POWER PLANT - PRESSURIZER SURGE, SPRAY, SAFETY, AND RELIEF NOZZLE WELD SUSCEPTIBILITY TO PRIMARY WATER STRESS-CORROSION CRACKING (TAC NO. MD4154)
Dear Mrs. Korsnick:
This letter acknowledges the receipt of information from R.E. Ginna Nuclear Power Plant, LLC pertaining to the pressurizer surge, spray, safety, and relief nozzle and safe end welds at the R.E. Ginna Nuclear Power Plant.
The discovery, in October 2006, of five circumferential indications in three Alloy 82/182 dissimilar metal (DM) welds on the pressurizer at the Wolf Creek Generating Station (Wolf Creek) raised safety concerns based on the size and location of the indications. At Wolf Creek, three indications were in the pressurizer surge nozzle-to-safe end weld, and two separate indications were in the safety and relief nozzle-to-safe end welds. These findings also indicated that significant concerns might exist with the inspection schedules for addressing the pressurizer weld concerns issued by the industry-sponsored Materials Reliability Program (MRP), in Primary System Piping Butt Weld Inspection and Evaluation Guideline (MRP-139).
The Nuclear Regulatory Commission (NRC) is concerned about the pressurizer surge nozzle-to-safe end weld indications, as this is the first time that multiple circumferential primary water stress-corrosion cracking (PWSCC) indications have been identified in a weld. This condition calls into question the degree of safety margin present in past structural integrity evaluations for flawed DM welds susceptible to PWSCC, since multiple stress-corrosion cracking flaws may grow independently and ultimately grow together, significantly reducing the time from flaw initiation to leakage or rupture.
Based on discussions with the NRC staff, licensees of plants susceptible to this condition have committed to enhanced inspection frequency and reactor coolant system leakage monitoring until actions to mitigate the potential of PWSCC in the affected welds have been completed.
In your letter dated January 30, 2007 (Agencywide Documents Access & Management System (ADAMS) Accession Number ML070380097), you stated that the pressurizer at R.E. Ginna Nuclear Power Plant does not have Alloy 82/182 butt welds. As a result, your response adequately addresses the concerns that the NRC has at this time regarding PWSCC susceptibility of these welds.
M. Korsnick This completes the NRC staff efforts on TAC No. MD4154 for the review associated with this issue. If you have any questions regarding this matter, please contact the R.E. Ginna Project Manager, Douglas Pickett, at 301-415-1364.
Sincerely,
/RA/
Catherine Haney, Director Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-244 cc: See next page
ML071340129 OFFICE LPL1-1/PE LPL1-1/LA LPL1-1/PM CPNB CPNB/BC LPL1-1/BC D/DORL NAME DWoodyatt SLittle DPickett TLupold TChan MKowal CHaney DATE 05/31/ 07 5 /31/ 07 5/31/ 07 6/01/ 07 6 /01/ 07 6/05/ 07 6 /06 / 07
R.E. Ginna Nuclear Power Plant cc:
Mr. Michael J. Wallace President R.E. Ginna Nuclear Power Plant, LLC c/o Constellation Energy 750 East Pratt Street Baltimore, MD 21202 Mr. John M. Heffley Senior Vice President and Chief Nuclear Officer Constellation Generation Group 1997 Annapolis Exchange Parkway Suite 500 Annapolis, MD 21401 Kenneth Kolaczyk, Sr. Resident Inspector R.E. Ginna Nuclear Power Plant U.S. Nuclear Regulatory Commission 1503 Lake Road Ontario, NY 14519 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Mr. Peter R. Smith, President New York State Energy, Research, and Development Authority 17 Columbia Circle Albany, NY 12203-6399 Mr. Carey W. Fleming, Esquire Senior Counsel - Nuclear Generation Constellation Generation Group, LLC 750 East Pratt Street, 17th Floor Baltimore, MD 21202 Mr. Charles Donaldson, Esquire Assistant Attorney General New York Department of Law 120 Broadway New York, NY 10271 Ms. Thelma Wideman, Director Wayne County Emergency Management Office Wayne County Emergency Operations Center 7336 Route 31 Lyons, NY 14489 Ms. Mary Louise Meisenzahl Administrator, Monroe County Office of Emergency Preparedness 1190 Scottsville Road, Suite 200 Rochester, NY 14624 Mr. Paul Eddy New York State Department of Public Service 3 Empire State Plaza, 10th Floor Albany, NY 12223