ML091030490

Evaluation of 2007 (Cycle 15) Steam Generator Tube Inspections

ML091030490
Person / Time
Site:	San Onofre
Issue date:	04/15/2009
From:	Kalyanam N Plant Licensing Branch IV
To:	Ridenoure R Southern California Edison Co
Kalyanam N, NRR/DORL/LPL4, 415-1480
References
TAC MD9458
Download: ML091030490 (3)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 April 15, 2009 Mr. Ross T. Ridenoure Senior Vice President and Chief Nuclear Officer Southern California Edison Company San Onofre Nuclear Generating Station P.O. Box 128 San Clemente, CA 92674-0128

SUBJECT:

SAN ONOFRE NUCLEAR GENERATING STATION, UNIT 2 - EVALUATION OF 2007 (CYCLE 15) STEAM GENERATOR TUBE INSPECTIONS (TAC NO. MD9458)

Dear Mr. Ridenoure:

By letter dated June 19, 2008, Southern California Edison (the licensee) submitted information pertaining to its 2007 steam generator (SG) tube inspections at the San Onofre Nuclear Generating Station, Unit 2 (SONGS 2) during the Cycle 15 refueling outage (U2C15).

In addition to the above report, the U.S. Nuclear Regulatory Commission (NRC) staff summarized additional information provided by the licensee in support of the December 14, 2007, conference call concerning the 2007 SG tube inspections at SONGS 2 in a letter dated January 22, 2008.

The NRC staff has completed its review of these reports and concludes that the licensee provided the information required by their technical specifications and that no additional follow up is required at this time. The staff's review of the reports is enclosed.

Sincerely, N. Kalyanam, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-361

Enclosure:

As stated cc w/encl: Distribution via Listserv

SUMMARY

OF REVIEW BY THE OFFICE OF NUCLEAR REACTOR REGULATION SAN ONOFRE NUCLEAR GENERATING STATION, UNIT 2 EVALUATION OF THE STEAM GENERATOR INSPECTIONS PERFORMED DURING THE 2007 REFUELING OUTAGE DOCKET NO. 50-361 By letter dated June 19, 2008 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML081780098), Southern California Edison (SCE, the licensee) submitted information pertaining to its 2007 steam generator (SG) tube inspections at the San Onofre Nuclear Generating Station, Unit 2 (SONGS 2) during the Cycle 15 refueling outage. In addition to the above report, the U.S. Nuclear Regulatory Commission (NRC) staff summarized additional information provided by the licensee in support of the December 14, 2007, conference call concerning the 2007 SG tube inspections at SONGS 2 in a letter dated January 22,2008 (ADAMS Accession No. ML080180164).

There are two Combustion Engineering Model 3410 SGs at SONGS 2. Each SG has 9350 mill annealed, Alloy 600 tubes. The tubes have an outside diameter of 0.75 inches, and a wall thickness of 0.048 inches. Carbon steel eggcrate tube supports, diagonal straps, and vertical straps support the tubes at various locations. The tubes were expanded through the full depth of the tubesheet using an explosive process.

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 (e.g., tube plugging) taken in response to the inspection findings.

The results of the 2007 inspection were similar to those in prior outages. No degradation of the batwing supports was observed. This is the last planned inspection of these SGs since they will be replaced during the fall 2009 refueling outage.

Based on a review of the information provided by the licensee, the NRC staff concludes that the licensee provided the information required by their technical specifications. The SG tube inspections at SONGS 2 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 u~its.

Enclosure

ML091030490 *Tech Staff Input OFFICE NRR/LPL4/PM NRR/LPL4/LA NRR/DCI/CSGB/BC NRR/LPL4/BC NRR/LPL4/PM NAME NKalyanam JBurkhardt MYoder* MMarkley NKalyanam DATE 4/15/09 4/15/09 4/9109 4/15/09 4/15/09