ML062340490
| ML062340490 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| 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 Duke Energy Corporation 526 South Church Street P. O. Box 1006 Mail Code = EC07H Charlotte, North Carolina 28201-1006 Manager, LIS NUS Corporation 2650 McCormick Dr., 3rd Floor Clearwater, FL 34619-1035 Senior Resident Inspector U.S. Nuclear Regulatory Commission 7812B Rochester Highway Seneca, SC 29672 Mr. Henry Porter, Director Division of Radioactive Waste Management Bureau of Land and Waste Management Dept. of Health and Env. Control 2600 Bull St.
Columbia, SC 29201-1708 Mr. Michael A. Schoppman Framatome ANP 1911 North Ft. Myer Dr.
Suite 705 Rosslyn, VA 22209 Mr. B. G. Davenport Regulatory Compliance Manager 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 Mr. R. L. Gill, Jr.
Manager - Nuclear Regulatory Issues and Industry Affairs Duke Energy Corporation 526 S. Church St.
Mail Stop EC05P Charlotte, NC 28202 Division of Radiation Protection NC Dept of Environment, Health, & Natural Resources 3825 Barrett Dr.
Raleigh, NC 27609-7721 Mr. Peter R. Harden, IV VP-Customer Relations and Sales Westinghouse Electric Company 6000 Fairview Road 12th Floor Charlotte, NC 28210 Mr. Henry Barron Group Vice President, Nuclear Generation and Chief Nuclear Officer P.O. Box 1006-EC07H Charlotte, NC 28201-1006 Mr. Bruce H. Hamilton Vice President, Oconee Site Duke Energy Corporation 7800 Rochester Highway Seneca, SC 29672