ML081970092
| ML081970092 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 07/22/2008 |
| From: | Richard Ennis NRC/NRR/ADRO/DORL/LPLI-2 |
| To: | Levis W Public Service Enterprise Group |
| Ennis R, NRR/DORL, 415-1420 | |
| References | |
| TAC MD7172 | |
| Download: ML081970092 (5) | |
Text
July 22, 2008 Mr. William Levis President & Chief Nuclear Officer PSEG Nuclear LLC - N09 Post Office Box 236 Hancocks Bridge, NJ 08038
SUBJECT:
REVIEW OF STEAM GENERATOR TUBE INSPECTION REPORT FOR SPRING 2007 - SALEM NUCLEAR GENERATING STATION, UNIT NO. 1 (TAC NO. MD7172)
Dear Mr. Levis:
By letter dated October 10, 2007 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML072970094), PSEG Nuclear LLC (PSEG) submitted a report summarizing the steam generator tube inspections performed at Salem Nuclear Generating Station, Unit No. 1 (Salem Unit 1) during the spring 2007 refueling outage (1R18). This information was submitted in accordance with Salem Unit 1 Technical Specification (TS) 6.9.1.10. Additional information concerning these inspections was provided in PSEGs letter dated April 30, 2008 (ADAMS Accession No. ML081290513).
The Nuclear Regulatory Commission staff has completed its review of your submittals as documented in the enclosed evaluation. The staff concludes that PSEG has provided the information required by the TSs and that no additional follow-up is required at this time. This completes the NRC staff efforts for TAC No. MD7172.
If you have any questions regarding this matter, I may be reached at 301-415-1420.
Sincerely,
/ra/
Richard B. Ennis, Senior Project Manager Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-272
Enclosure:
As stated cc w/encl: See next page
The Nuclear Regulatory Commission staff has completed its review of your submittals as documented in the enclosed evaluation. The staff concludes that PSEG has provided the information required by the TSs and that no additional follow-up is required at this time. This completes the NRC staff efforts for TAC No. MD7172.
If you have any questions regarding this matter, I may be reached at 301-415-1420.
Sincerely,
/ra/
Richard B. Ennis, Senior Project Manager Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-272
Enclosure:
As stated cc w/encl: See next page DISTRIBUTION:
PUBLIC RidsAcrsAcnw_MailCTR Resource LPL1-2 Reading RidsRgn1MailCenter Resource RidsNrrDorlLpl1-2 Resource AHiser, DCI/CSGB RidsNrrLAABaxter Resource KKarwoski, DCI/CSGB RidsNrrPMREnnis Resource AJohnson, DCI/CSGB RidsOgcRp Resource ADAMS Accession No.: ML081970092
- By memo dated 6/25/08 OFFICE LPL1-2/PM LPL 1-2/LA CSGB/BC LPL1-2/BC NAME REnnis ABaxter AHiser HChernoff DATE 7/15/08 7/21/08 6/25/08 7/22/08
Salem Nuclear Generating Station, Unit Nos. 1 and 2 cc:
Mr. Thomas Joyce Senior Vice President - Operations PSEG Nuclear P.O. Box 236 Hancocks Bridge, NJ 08038 Mr. Dennis Winchester Vice President - Nuclear Assessment PSEG Nuclear P.O. Box 236 Hancocks Bridge, NJ 08038 Mr. Robert Braun Site Vice President - Salem PSEG Nuclear P.O. Box 236 Hancocks Bridge, NJ 08038 Mr. Carl Fricker Vice President - Operations Support PSEG Nuclear P.O. Box 236 Hancocks Bridge, NJ 08038 Mr. George Gellrich Plant Manager - Salem PSEG Nuclear P.O. Box 236 Hancocks Bridge, NJ 08038 Mr. James Mallon Manager - Licensing PSEG Nuclear P.O. Box 236 Hancocks Bridge, NJ 08038 Mr. Steven Mannon Manager - Salem Regulatory Assurance PSEG Nuclear P.O. Box 236 Hancocks Bridge, NJ 08038 Mr. 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 Mr. Paul Bauldauf, P.E., Asst. Director Radiation Protection Programs NJ Department of Environmental Protection and Energy CN 415 Trenton, NJ 08625-0415 Mr. Brian Beam Board of Public Utilities 2 Gateway Center, Tenth Floor Newark, NJ 07102 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Senior Resident Inspector Salem Nuclear Generating Station U.S. Nuclear Regulatory Commission Drawer 0509 Hancocks Bridge, NJ 08038
Enclosure EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION STEAM GENERATOR TUBE INSPECTION REPORT FOR SPRING 2007 SALEM NUCLEAR GENERATING STATION, UNIT NO. 1 DOCKET NO. 50-272
1.0 INTRODUCTION
By letter dated October 10, 2007 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML072970094), PSEG Nuclear LLC (PSEG or the licensee) submitted a report summarizing the steam generator (SG) tube inspections performed at Salem Nuclear Generating Station, Unit No. 1 (Salem Unit 1) during the spring 2007 refueling outage (1R18).
This information was submitted in accordance with Salem Unit 1 Technical Specification (TS) 6.9.1.10. Additional information concerning these inspections was provided in PSEGs letter dated April 30, 2008 (ADAMS Accession No. ML081290513).
2.0 BACKGROUND
Salem 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 tubesheet was drilled on a square pitch with 0.98-inch spacing. The U-bends in rows 1 through 10 were stress relieved after bending. Eight Type 405 stainless steel support plates, which have broached quatrefoil holes, support the vertical section of the tubes, and chrome-plated Alloy 600 anti-vibration bars support the U-bend section of the tubes.
At the time of this inspection the SGs had accumulated 95.244 Effective Full Power Months of operation.
3.0 EVALUATION The licensee provided the scope, extent, methods, and results of their SG tube inspections in the submittals referenced above. After review of the information provided by the licensee, the Nuclear Regulatory Commission (NRC) staff has the following comments/observations:
The licensees rotating probe examinations of dents and dings focused on those tubes that had eddy current signals representative of higher residual stresses. The majority of dents and dings are not associated with the tubes with potentially higher residual stresses. A significant number of rotating probe examinations was not performed at these latter locations (i.e., tubes with potentially higher residual stresses).
Only 1.5-percent of new wear indications at anti-vibration bars were inspected with a rotating coil. To determine the nature of a bobbin coil indication, inspections with a rotating coil are normally performed when a bobbin indication is identified. By not performing rotating probe examinations, the nature of the degradation cannot be confirmed. That is, the degradation cannot be confirmed to be volumetric, and it cannot be confirmed to coincide with the support structure. Recently, one plant identified that a bobbin coil indication was attributed not only to wear at the anti-vibration bar but also to wear associated with contact with a neighboring tube. It is important to know the cause of a bobbin coil signal in order to properly size the indication and to assess its integrity over the next operating cycle.
The licensee described their methodology for determining the repair limit for wear associated with anti-vibration bars. Although the NRC staff did not review this methodology in detail, the staff notes that licensees have effectively managed this degradation mechanism in the past.
4.0 CONCLUSION
The NRC staff concludes that the licensee provided the information required by the Salem Unit 1 TSs and that no additional follow-up is required at this time. 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. B. Johnson Date: July 22, 2008