ML083310252
| ML083310252 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 12/03/2008 |
| From: | Balwant Singal Plant Licensing Branch IV |
| To: | Edington R Arizona Public Service Co |
| Singal, Balwant K, NRR/DORL 301-415-3016 | |
| References | |
| TAC MD7759 | |
| Download: ML083310252 (3) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 December 3, 2008 Mr. Randall K. Edington Executive Vice President Nuclear/
Chief Nuclear Officer Mail Station 7602 Arizona Public Service Company P. O. Box 52034 Phoenix, AZ. 85072-2034
SUBJECT:
PALO VERDE NUCLEAR GENERATING STATION, UNIT 1 -
SUMMARY
OF THE STAFF'S REVIEW OF THE 2007 STEAM GENERATOR TUBE INSPECTIONS PERFORMED DURING REFUELING OUTAGE 13 (TAC NO. MD7759)
Dear Mr. Edington:
By letter dated January 2,2008 (Agencywide Documents and Access Management System (ADAMS) Accession No. ML080090193), as supplemented by letter dated October 3,2008 (ADAMS Accession No. ML082890538), Arizona Public Service Company (the licensee) submitted information summarizing the results of the 2007 steam generator tube inspections at the Palo Verde Nuclear Generating Station (PVNGS), Unit 1, performed during the 13th refueling outage.
The U.S. Nuclear Regulatory Commission staff has completed its review of these reports and concludes that the licensee provided the information required by PVNGS, Unit 1, Technical Specifications and that no additional follow-up is required at this time. The staff's review of this report is enclosed. Please contact me at 301-415-3016 with any questions.
Sincerely, Sb<:>o. 'wc-" ~,~
Balwant K. Singal, Senior Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. STN 50-528
Enclosure:
As stated cc w/encl: Distribution via Listserv
STAFF EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO RESULTS OF STEAM GENERATOR TUBE INSPECTION PERFORMED DURING 13TH REFUELING OUTAGE ARIZONA PUBLIC SERVICE COMPANY. ET AL.
PALO VERDE NUCLEAR GENERATING STATION, UNIT 1 DOCKET NO. STN 50-528 By letter dated January 2, 2008 (Agencywide Documents and Access Management System (ADAMS) Accession No. ML080090193), as supplemented by letter dated October 3,2008 (ADAMS Accession No. ML082890538), Arizona Public Service Company (the licensee) submitted information pertaining to its 2007 steam generator (SG) tube inspections at the Palo Verde Nuclear Generating Station (PVNGS), Unit 1. These inspections were performed during the 13th refueling outage of PVNGS, Unit 1.
PVNGS, Unit 1, has two SGs, each having 12.580 thermally treated Alloy 690 tubes with an outside diameter of 0.75 inches and a wall thickness of 0.042 inches. Ferritic stainless steel eggcrate tube supports, diagonal bars, and/or vertical straps support the tubes at various locations.
The licensee provided the scope. extent, methods, and results of its SG tube inspections in the documents referenced above. In addition, the licensee described corrective actions (i.e.. tube plugging) taken in response to the inspection findings.
The following observations are noted in regard to the licensee's 2007 inspections:
The front row of tubes adjacent to the Central Cavity Wear region (formerly called the Batwing Stay Cylinder region) were stabilized and plugged prior to the installation of the PVNGS, Unit 1, replacement steam generators (RSGs). This decision was based on initial operating experience with the Unit 2 RSGs where an unexpected amount of wear was observed in this region.
The PVNGS, Unit 1, RSGs tubes were examined in locations where damage from tube packaging was possible. A rotating coil probe was used to inspect 100 percent of dents greater than 0.5 volts in RSG 11 (784 tubes) and RSG 12 (556 tubes) during the preservice inspection. No tubes in RSG 11 or 12 were plugged because of the inspections.
Based on a review of the information provided, the U.S. Nuclear Regulatory Commission (NRC) staff concludes that the licensee provided the information required by its 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.
Enclosure
ML082890538), Arizona Public Service Company (the licensee) submitted information summarizing the results of the 2007 steam generator tube inspections at the Palo Verde Nuclear Generating Station (PVNGS), Unit 1, performed during the 13th refueling outage.
The U.S. Nuclear Regulatory Commission staff has completed its review of these reports and concludes that th.e licensee provided the information required by PVNGS, Unit 1, Technical Specifications and that no additional follow-up is required at this time. The staff's review of this report is enclosed. Please contact me at 301-415-3016 with any questions.
Sincerely, IRAI Balwant K. Singal, Senior Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. STN 50-528
Enclosure:
As stated cc w!encl: Distribution via Listserv DISTRIBUTION:
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