ML020840670
| ML020840670 | |
| Person / Time | |
|---|---|
| Site: | Oconee  (DPR-055) |
| Issue date: | 04/01/2002 |
| From: | Olshan L NRC/NRR/DLPM/LPD2 |
| To: | Mccollum W Duke Energy Corp |
| Olshan L N, NRR/DLPM, 415-1419 | |
| References | |
| TAC MB3180 | |
| Download: ML020840670 (5) | |
Text
April 1, 2002 Mr. William R. McCollum, Jr.
Vice President, Oconee Site Duke Energy Corporation 7800 Rochester Highway Seneca, SC 29672
SUBJECT:
SUMMARY
OF TELEPHONE CONFERENCES WITH DUKE ENERGY RE: STEAM GENERATOR INSPECTION RESULTS AT OCONEE NUCLEAR STATION, UNIT 3 (TAC NO. MB3180)
Dear Mr. McCollum:
On November 15 and November 29, 2001, your staff and our staff participated in conference calls regarding the steam generator inspection activities at Oconee Nuclear Station, Unit 3.
We documented our request and suggested agenda for these calls in our letter dated October 26, 2001. Enclosure 1 is a brief summary of the calls, and Enclosure 2 is material your staff sent us in preparation for the calls.
Based on the information discussed during the calls, we did not identify any issues requiring further discussion.
Sincerely,
/RA/
Leonard N. Olshan, Project Manager, Section 1 Project Directorate II Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-287
Enclosures:
- 1. Summary of Conference Call With Duke Energy Regarding Current Steam Generator Inspection Results at Oconee Unit 3
April 1, 2002 Mr. William R. McCollum, Jr.
Vice President, Oconee Site Duke Energy Corporation 7800 Rochester Highway Seneca, SC 29672
SUBJECT:
SUMMARY
OF TELEPHONE CONFERENCES WITH DUKE ENERGY RE: STEAM GENERATOR INSPECTION RESULTS AT OCONEE NUCLEAR STATION, UNIT 3 (TAC NO. MB3180)
Dear Mr. McCollum:
On November 15 and November 29, 2001, your staff and our staff participated in conference calls regarding the steam generator inspection activities at Oconee Nuclear Station, Unit 3.
We documented our request and suggested agenda for these calls in our letter dated October 26, 2001. Enclosure 1 is a brief summary of the calls, and Enclosure 2 is material your staff sent us in preparation for the calls.
Based on the information discussed during the calls, we did not identify any issues requiring further discussion.
Sincerely,
/RA/
Leonard N. Olshan, Project Manager, Section 1 Project Directorate II Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-287
Enclosures:
- 1. Summary of Conference Call With Duke Energy Regarding Current Steam Generator Inspection Results at Oconee Unit 3
- 2. Telefax entitled, ONS 3EOC-19 S/G Inspection Plans and Results cc w/encls: See next page DISTRIBUTION:
PUBLIC CHawes PDII-1 R/F OGC RLaufer ACRS LOlshan RHaag, RII Accession Number: ML020840670
- No major changes to SE OFC PDII-1/PM PDII-1/LA PDII-1/ASC EMCB/SC*
NAME LOlshan CHawes RLaufer LLund DATE 3/29/02 3/28/02 3/29/02 3/4/02 OFFICIAL RECORD COPY
SUMMARY
OF CONFERENCE CALL WITH DUKE ENERGY REGARDING CURRENT STEAM GENERATOR INSPECTION RESULTS AT OCONEE, UNIT 3 The NRC staff participated in conference calls with Duke Energy (the licensee) on November 15 and November 29, 2001, to discuss the plans and results of the steam generator tube inspection activities at Oconee Nuclear Station, Unit 3 (Oconee 3).
Topics discussed during the conference calls consisted of initial eddy current testing scope, scope expansion plans, indications identified to-date, repair/plugging plans, new inspection findings, in-situ pressure test plans and actions taken in response to lessons learned from the Indian Point 2 tube failure.
During the November 15, 2001, conference call, the licensee discussed its plans for addressing the potential for plugged tubes to affect adjacent active tubes at Oconee 3. As a result of findings at Three Mile Island Unit 1 (TMI-1), discussed in NRC Information Notice 2002-02, Recent Experience with Plugged Steam Generator Tubes (ML013480327), the licensee elected to deplug and inspect approximately 48 tubes with alloy 600 plugs and 73 tubes whose original alloy 600 plugs were replaced with alloy 690 plugs. This population was intended to include all tubes which passed through drilled hole locations at the tube support plates. These tubes are located in the outer periphery of the tube bundle. The licensee was not planning to deplug and inspect any tube that had been originally repaired with an alloy 690 plug on the basis that the inspections at TMI-1 did not reveal any water or swelling in these tubes and that there were significant improvements in the installation process when alloy 690 plugs were installed. However, because the number of inspections in alloy 690 plugs at TMI-1 were very limited, the staff suggested that the licensee may want to consider deplugging some of the outer periphery tubes originally plugged with alloy 690 plugs to further support the TMI-1 findings.
The November 29, 2001, conference call focused on the Oconee 3 steam generator tube inspection results. At the time of this conference call, the inspections were completed and the plant was performing tube plugging in the steam generators.
As a result of the inspections, 165 eddy current indications were found in steam generator A and 81 in steam generator B. Most of them were axial in nature and in the freespan region. Of the 6 tubes with indications at dented locations, some were axial in nature while others were circumferential. These indications were estimated to be short and shallow with the circumferential indications measuring less than 0.7 inch in arc length. No new degradation mechanisms were detected during this outage.
None of the indications detected during the outage exceeded the criteria which would require the performance of an in-situ pressure test. Nonetheless, the licensee elected to in-situ pressure test several indications to three times the normal operating differential pressure. The indications tested included axial flaws (one had the highest plus-point voltage, one with the longest length which was a 7-inch long axial indication), and several volumetric flaws attributed to impingement. The deepest of these was estimated to be 75 percent through-wall. A total of 13 tubes were in-situ tested to three times the normal operating differential pressure. None of these indications leaked during the test.
The licensee plans to plug a total of 354 tubes as a result of the inspections. This includes the tubes with the 246 indications discussed above and 110 tubes to capture non-stabilized plugged tubes. The latter tubes were plugged in response to the findings at TMI-1 (i.e., to prevent a non-stabilized tube from severing and impacting an active tube).
Based on the information discussed during the conference calls, the staff did not identify any issues requiring further discussion.
Subsequent to the conference calls, the licensee provided additional inspection results in letters dated December 6, 2001, End-of-Cycle 19 Steam Generator Tube Inspection - Report on Indication of Circumferential Defects (ML020170422), and December 20, 2001, Steam Generator Inservice Inspection - Steam Generator Tube Plugging and Repair 30-day Report (ML020240179).
Also, during a public meeting on January 31, 2002 (ML020580478), it was indicated that 4 tubes in the outer periphery of the tube bundle had been plugged with alloy 600 plugs and were not deplugged and inspected during the outage. These plugs had been repaired following installation and were not identified until after the inspections were completed.
Oconee Nuclear Station cc:
Ms. Lisa F. Vaughn Legal Department (PBO5E)
Duke Energy Corporation 422 South Church Street Charlotte, North Carolina 28201-1006 Anne W. Cottingham, Esquire Winston and Strawn 1400 L Street, NW Washington, DC 20005 Manager, LIS NUS Corporation 2650 McCormick Drive, 3rd Floor Clearwater, Florida 34619-1035 Senior Resident Inspector U. S. Nuclear Regulatory Commission 7812B Rochester Highway Seneca, South Carolina 29672 Mr. Henry Porter, Director Division of Radioactive Waste Management Bureau of Land and Waste Management Department of Health and Environmental Control 2600 Bull Street Columbia, South Carolina 29201-1708 Mr. Michael A. Schoppman Framatome ANP 1911 North Ft. Myer Drive Suite 705 Rosslyn, VA 22209 Mr. L. E. Nicholson Compliance Manager Duke Energy Corporation Oconee Nuclear Site 7800 Rochester Highway Seneca, South Carolina 29672 Ms. Karen E. Long Assistant Attorney General North Carolina Department of Justice P. O. Box 629 Raleigh, North Carolina 27602 Mr. C. Jeffrey Thomas Manager - Nuclear Regulatory Licensing Duke Energy Corporation 526 South Church Street Charlotte, North Carolina 28201-1006 Mr. Richard M. Fry, Director Division of Radiation Protection North Carolina Department of Environment, Health, and Natural Resources 3825 Barrett Drive Raleigh, North Carolina 27609-7721 Mr. Peter R. Harden, IV VP-Customer Relations and Sales Westinghouse Electric Company 6000 Fairview Road 12th Floor Charlotte, North Carolina 28210