ML062340490

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Meeting Summary, Spring 2006 Steam Generator Inspection
ML062340490
Person / Time
Site: Oconee Duke Energy icon.png
Issue date: 11/28/2006
From: Olshan L
NRC/NRR/ADRO/DORL/LPLII-1
To:
Duke Power Co
Olshan L N, NRR/DORL, 415-1419
Shared Package
ML062340511 List:
References
TAC MD1492
Download: ML062340490 (4)


Text

November 28, 2006 LICENSEE: DUKE POWER COMPANY LLC (DUKE)

FACILITY: OCONEE NUCLEAR STATION, UNIT 3 (Oconee Unit 3)

SUBJECT:

SUMMARY

OF MAY 9, 2006, CONFERENCE CALL TO DISCUSS THE SPRING 2006 STEAM GENERATOR INSPECTION (TAC NO. MD1492)

On May 9, 2006, the Nuclear Regulatory Commission (NRC) staff participated in a conference call with Duke (the licensee) to discuss the scope, results, and status of the spring 2006 steam generator tube inspections at Oconee Unit 3. The NRC participants were E. Murphy, K. Karwoski, A. Hiser, and R. Chou. The Duke participants were J. Weast, M. Robinson, J. Gilreath, D. Mayes, S. Capps, and P. Downing.

Oconee Unit 3 is a two-loop, pressurized-water reactor with once-through steam generators (OTSGs) manufactured by Babcock & Wilcox, Canada. The Oconee Unit 3 OTSGs are replacement OTSGs installed during the previous refueling outage (fall 2004). The ongoing inspections at Oconee Unit 3 are the first inservice inspections of the replacement OTSGs at this unit.

A major point of interest to the NRC staff going into the call was the state of tube wear at Oconee Unit 3. The first inservice inspection of identical replacement OTSGs at Oconee Unit 1 in the spring of 2005 and Oconee Unit 2 in the fall of 2005, revealed unexpected, widespread wear degradation of the tubing at tube support plate locations.

In advance of the phone call, the licensee provided a written summary of its inspection program, status, and results, to date, which is enclosed. This summary addressed all discussion points that had been requested by the NRC staff prior to the phone call. During the phone call, the licensee walked the NRC staff through the summary material.

The licensee had completed 88 percent of its planned inspections in the 3A OTSG and 82 percent in the 3B OTSG at the time of the phone call. As was observed previously at Oconee Units 1 and 2, widespread wear degradation was observed at the tube support plates (i.e.,

support plates 8 through 14). For Unit 3, 10.7 percent of the tubes inspected in 3A OTSG and 4.4 percent of the tubes inspected in 3B OTSG contained wear indications. This was somewhat fewer than the percentages found for Unit 1 (11.5 percent in 1A OTSG and 9.3 percent in 1B OTSG), but somewhat more than found for Unit 2 (3.2 percent in 2A OTSG and 4.5 percent in 2B OTSG). The deepest indication found to date at Unit 3 is 26 percent through-wall (TW), compared to the deepest indication of 42 percent TW at Unit 1 and 32 percent TW at Unit 2. Based on the indications found to date, the licensee projects that no tubes will require plugging at Unit 3 to ensure tube integrity throughout the next operating cycle to the next scheduled inspection. At Units 1 and 2, 48 and 3 tubes, respectively, required plugging for this purpose.

Duke The licensee met with the NRC staff on April 10, 2006 (ML061100211) to discuss the status of the licensees ongoing program to identify the contributing causes of the wear degradation at the Oconee units and potential measures to mitigate future wear. This program includes, in part, the installation of accelerometers on the OTSG upper-channel head and steam line and installation of pressure transducers through various inspection port covers at each of the Oconee units to acquire data on excitation sources that may be contributing to the wear problem. During the call on May 9, 2006, the licensee confirmed that this instrumentation package was being installed at Unit 3. During the April 10, 2006 meeting, the licensee stated that it expected to be reaching some conclusions on the major contributing factors toward the end of 2006.

/RA/

Leonard N. Olshan, Project Manager Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-287

Enclosure:

Steam Generator Tube Inspection Discussion Points of May 9, 2006 cc w/encl.: See next page

Duke November 28, 2006 The licensee met with the NRC staff on April 10, 2006 (ML061100211) to discuss the status of the licensees ongoing program to identify the contributing causes of the wear degradation at the Oconee units and potential measures to mitigate future wear. This program includes, in part, the installation of accelerometers on the OTSG upper-channel head and steam line and installation of pressure transducers through various inspection port covers at each of the Oconee units to acquire data on excitation sources that may be contributing to the wear problem. During the call on May 9, 2006, the licensee confirmed that this instrumentation package was being installed at Unit 3. During the April 10, 2006 meeting, the licensee stated that it expected to be reaching some conclusions on the major contributing factors toward the end of 2006.

/RA/

Leonard N. Olshan, Project Manager Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-287

Enclosure:

Steam Generator Tube Inspection Discussion Points of May 9, 2006 cc w/encl.: See next page Distribution:

PUBLIC LPL2-1 r/f RidsNrrDorlLpl2-1 (EMarinos)

RidsNrrPMLOlshan (Hard copy)

RidsNrrLAMOBrien (Hard copy)

RidsOgcRp RidsAcrsAcnwMailCenter R. Jasinski, NRR S. Lee, Rgn II RidsRgn2MailCenter Package: ML062340511

Enclosure:

ML062360217 (Conf Call)

ML062360465 (Meeting Hand Out)

Conf Call Summary: ML062340490 NRC-001 OFFICE LPL2-1/PM LPL2-1/LA LPL2-1/BC NAME LOlshan:ckg MOBrien EMarinos DATE 11/24/06 11/22/06 11/28/06 OFFICIAL RECORD COPY

Oconee Nuclear Station, Units 1, 2, and 3 cc:

Ms. Lisa F. Vaughn Mr. R. L. Gill, Jr.

Duke Energy Corporation Manager - Nuclear Regulatory 526 South Church Street Issues and Industry Affairs P. O. Box 1006 Duke Energy Corporation Mail Code = EC07H 526 S. Church St.

Charlotte, North Carolina 28201-1006 Mail Stop EC05P Charlotte, NC 28202 Manager, LIS NUS Corporation Division of Radiation Protection 2650 McCormick Dr., 3rd Floor NC Dept of Environment, Health, & Natural Clearwater, FL 34619-1035 Resources 3825 Barrett Dr.

Senior Resident Inspector Raleigh, NC 27609-7721 U.S. Nuclear Regulatory Commission 7812B Rochester Highway Mr. Peter R. Harden, IV Seneca, SC 29672 VP-Customer Relations and Sales Westinghouse Electric Company Mr. Henry Porter, Director 6000 Fairview Road Division of Radioactive Waste Management 12th Floor Bureau of Land and Waste Management Charlotte, NC 28210 Dept. of Health and Env. Control 2600 Bull St. Mr. Henry Barron Columbia, SC 29201-1708 Group Vice President, Nuclear Generation and Chief Nuclear Officer Mr. Michael A. Schoppman P.O. Box 1006-EC07H Framatome ANP Charlotte, NC 28201-1006 1911 North Ft. Myer Dr.

Suite 705 Mr. Bruce H. Hamilton Rosslyn, VA 22209 Vice President, Oconee Site Duke Energy Corporation Mr. B. G. Davenport 7800 Rochester Highway Regulatory Compliance Manager Seneca, SC 29672 Oconee Nuclear Site Duke Energy Corporation ON03RC 7800 Rochester Highway Seneca, SC 29672 Ms. Karen E. Long Assistant Attorney General NC Department of Justice P.O. Box 629 Raleigh, NC 27602