ML071060182

Pressurizer Surge, Spray, Safety, and Relief Nozzle Weld Susceptibility to Primary Water Stress Corrosion Cracking (TAC Nos. MD4179 and MD4180)

ML071060182
Person / Time
Site:	Salem
Issue date:	04/29/2007
From:	Catherine Haney Plant Licensing Branch III-2
To:	Levis W Public Service Enterprise Group
Ennis R, NRR/DORL, 415-1420
References
TAC MD4179, TAC MD4180
Download: ML071060182 (4)

Text

April 29, 2007 Mr. William Levis Senior Vice President & Chief Nuclear Officer PSEG Nuclear LLC - N09 Post Office Box 236 Hancocks Bridge, NJ 08038

SUBJECT:

SALEM NUCLEAR GENERATING STATION, UNIT NOS. 1 AND 2 -

PRESSURIZER SURGE, SPRAY, SAFETY, AND RELIEF NOZZLE WELD SUSCEPTIBILITY TO PRIMARY WATER STRESS-CORROSION CRACKING (TAC NOS. MD4179 AND MD4180)

Dear Mr. Levis:

This letter acknowledges the receipt of information from PSEG Nuclear LLC pertaining to the pressurizer surge, spray, safety, and relief nozzle and safe end welds at Salem Nuclear Generating Station, Unit Nos. 1 and 2 (Salem).

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 26, 2007 (Agencywide Documents Access & Management System (ADAMS) Accession Number ML070370185), you stated that the Salem pressurizers do 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.

W. Levis This completes the NRC staff efforts on TAC Nos. MD4179 and MD4180 for the review associated with this issue. If you have any questions regarding this matter, please contact the Salem Project Manager, Mr. Richard Ennis, at 301-415-1420.

Sincerely,

/ra/

Catherine Haney, Director Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-272 and 50-311 cc: See next page

ML071060182 OFFICE CPNB LPL1-2/PM LPL1-1/LA CPNB/BC LPL1-2/BC DORL/D NAME TLupold REnnis SLittle TChan HChernoff CHaney DATE 4/25/07 4/18/07 4/18/07 4/25/07 4/23/07 4/29/07 Salem Nuclear Generating Station, Unit Nos. 1 and 2 cc:

Mr. Dennis Winchester Mr. Paul Bauldauf, P.E., Asst. Director Vice President - Nuclear Assessment Radiation Protection Programs PSEG Nuclear NJ Department of Environmental P.O. Box 236 Protection and Energy Hancocks Bridge, NJ 08038 CN 415 Trenton, NJ 08625-0415 Mr. Thomas P. Joyce Site Vice President - Salem Mr. Brian Beam PSEG Nuclear Board of Public Utilities P.O. Box 236 2 Gateway Center, Tenth Floor Hancocks Bridge, NJ 08038 Newark, NJ 07102 Mr. George H. Gellrich Regional Administrator, Region I Plant Support Manager U.S. Nuclear Regulatory Commission PSEG Nuclear 475 Allendale Road P.O. Box 236 King of Prussia, PA 19406 Hancocks Bridge, NJ 08038 Senior Resident Inspector Mr. Carl J. Fricker Salem Nuclear Generating Station Plant Manager - Salem U.S. Nuclear Regulatory Commission PSEG Nuclear - N21 Drawer 0509 P.O. Box 236 Hancocks Bridge, NJ 08038 Hancocks Bridge, NJ 08038 Mr. James Mallon Manager - Licensing 200 Exelon Way, KSA 3-E Kennett Square, PA 19348 Mr. Steven Mannon Manager - Regulatory Assurance P.O. Box 236 Hancocks Bridge, NJ 08038 Jeffrie J. Keenan, Esquire PSEG Nuclear - N21 P.O. Box 236 Hancocks Bridge, NJ 08038 Township Clerk Lower Alloways Creek Township Municipal Building, P.O. Box 157 Hancocks Bridge, NJ 08038