ML080180172

Summary of 12/14/2007, Discussions on Steam Generator Tube Inspections

ML080180172
Person / Time
Site:	San Onofre
Issue date:	01/22/2008
From:	Kalyanam N NRC/NRR/ADRO/DORL/LPLIV
To:	Rosenblum R Southern California Edison Co
Kalyanam N, NRR/DORL/LPL4, 415-1480
Shared Package
ML080180164	List: ML080180172
References
TAC MD7406
Download: ML080180172 (6)

Text

January 22, 2008 Mr. Richard M. Rosenblum 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 -

SUMMARY

OF DECEMBER 14, 2007, DISCUSSIONS ON STEAM GENERATOR TUBE INSPECTIONS (TAC NO. MD7406)

Dear Mr. Rosenblum:

On December 14, 2007, the U.S. Nuclear Regulatory Commission (NRC) staff participated in a conference call with Southern California Edison (SCE) representatives regarding the 2007 steam generator tube inspections at San Onofre Nuclear Generating Station, Unit 2. A summary of the December 14, 2007, conference call is provided in the enclosure; the information supplied by SCE, in support of these discussions (handouts), is provided in an attachment to the enclosure. The NRC staff did not identify any issues that would warrant preventing the plant from starting up following its 15th refueling outage.

If you have any questions, please call me at (301) 415-1480.

Sincerely,

/RA/

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

Enclosure:

Summary of conference call cc w/encl: See next page

Pkg ML080180164, Summary/Encl ML080180172, Attachment ML080140420 (*) Tech Staff Input OFFICE DORL/LPL4/PM DORL/LPL4/LA DCI/CSGB/BC* DORL/LPL4/BC NAME NKalyanam JBurkhardt AHiser (*) THiltz DATE 1/22/08 1/22/2008 01/14/08 1/22/08

San Onofre Nuclear Generating Station (12/5/2007)

Units 2 and 3 cc:

Douglas K. Porter, Esquire Mayor Southern California Edison Company City of San Clemente 2244 Walnut Grove Avenue 100 Avenida Presidio Rosemead, CA 91770 San Clemente, CA 92672 Dr. David Spath, Chief Mr. James T. Reilly Division of Drinking Water and Southern California Edison Company Environmental Management San Onofre Nuclear Generating Station California Dept. of Health Services P.O. Box 128 850 Marina Parkway, Bldg P, 2nd Floor San Clemente, CA 92674-0128 Richmond, CA 94804 Mr. James D. Boyd Chairman, Board of Supervisors California State Liaison Officer County of San Diego Vice Chair and Commissioner 1600 Pacific Highway, Room 335 California Energy Commission San Diego, CA 92101 1516 Ninth Street, MS 31 Sacramento, CA 95814 Mark L. Parsons Deputy City Attorney Mr. Gary Butner City of Riverside Acting Branch Chief 3900 Main Street Department of Public Health Services Riverside, CA 92522 Radiologic Health Branch MS 7610, P.O. Box 997414 Mr. Gary L. Nolff Sacramento, CA 95899-7414 Assistant General Manager - Resources Riverside Public Utilities Mr. Ross T. Ridenoure City of Riverside, California Vice President and Site Manager 3901 Orange Street Southern California Edison Company Riverside, CA 92501 San Onofre Nuclear Generating Station P.O. Box 128 Regional Administrator, Region IV San Clemente, CA 92674-0128 U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Mr. A. Edward Scherer Arlington, TX 76011-8064 Director, Nuclear Regulatory Affairs Southern California Edison Company Mr. Michael L. De Marco San Onofre Nuclear Generating Station San Diego Gas & Electric Company P.O. Box 128 8315 Century Park Ct. CP21G San Clemente, CA 92674-0128 San Diego, CA 92123-1548 Resident Inspector San Onofre Nuclear Generating Station c/o U.S. Nuclear Regulatory Commission Post Office Box 4329 San Clemente, CA 92674

SUMMARY

OF DECEMBER 14, 2007, CONFERENCE CALL WITH SOUTHERN CALIFORNIA EDISON REGARDING THE FALL 2007 STEAM GENERATOR TUBE INSPECTION AT SAN ONOFRE NUCLEAR GENERATING STATION, UNIT 2 DOCKET NO. 50-361 On December 14, 2007, U.S. Nuclear Regulatory Commission staff participated in a conference call with Southern California Edison (the licensee) representative regarding the fall 2007 (2C15) steam generator (SG) tube inspection activities at San Onofre Nuclear Generating Station Unit 2 (SONGS 2). Prior to the conference call, the licensee provided a handout to facilitate the discussion. The conference call summarized below is based on the information provided by the licensee prior to the call.

Background information on the SONGS 2 SGs is provided on page 2 of the attachment. The SGs were originally designed with 9350 Alloy 600 mill annealed tubes. Through four separate outages, a total of 345 tubes in SG 88 and 189 tubes in SG 89 were sleeved. At the beginning of the current refueling outage, there were a total of 256 sleeves remaining in service. The Combustion Engineering-designed sleeves have a welded upper joint and a rolled lower joint.

This is the last eddy current inspection planned for these SGs. They are scheduled to be replaced during the fall 2009 refueling outage.

At the time of the call, eddy current testing (ECT) inspection by the bobbin probe was complete and approximately 98 percent of the ECT by +Point inspections were complete.

Additional clarifying information or information not included in the document provided by the licensee is summarized below.

Acronyms used by the licensee in the attachment include:

EFPY ------ effective full power years TSP ------ tube support plate TSH ------ tubesheet hot TSC ------ tubesheet cold TW ------ through wall FLDA ------ flaw length degraded area SAI ------ single axial indication EC ------ egg crate ET ------ eddy current testing PDA ------ percent degraded area CA ------ crack angle (PDA and CA only apply to circumferential indications)

The +Point probe exams in the tubesheet region were from 13 inches below the top of the tubesheet to 4 inches above the top of tubesheet to ensure the tubes were examined through the sludge pile.

Visual inspection for foreign objects was conducted in the annular region and center lane of the tubesheet. No foreign objects were identified during this outage.

ENCLOSURE

The criterion for preventatively plugging tubes due to tube support wear is > 30 percent through wall.

One sleeve in each generator was found partially obstructed. The tubes with these obstructed sleeves were scheduled to be plugged. These sleeves were both installed in the 1999 refueling outage. Even though the sleeves were partially obstructed, it was still possible to examine the sleeves with the eddy current probe.

Tube 31-165 in SG 88 has multiple axial indications at the fifth hot leg tube support plate. The indications are not aligned.

The diagonal bar tube supports (batwings) were verified intact through review of the bobbin coil eddy current data. There were no secondary side visual inspections in this region. Refer to Agencywide Documents Access and Management System (ADAMS) Accession No. ML063040307, Response to Request for Additional Information Regarding Report of Inservice Inspection of Steam Generator Tubes, Cycle 14, for more details on how the operating experience from a similar unit has been factored into the SONGS 2 inspection and data analysis techniques. SONGS 2 performed chemical cleaning of their SGs in refueling outage 2C9.

The staff did not identify any issues that required follow-up action at this time; however, the staff asked to be notified in the event that any unusual conditions were detected during the remainder of the outage.

ATTACHMENT SONGS Unit 2 Handout