ML13333B240
| ML13333B240 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 03/25/1985 |
| From: | Paulson W Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| LSO5-85-03-022, LSO5-85-3-22, NUDOCS 8503270459 | |
| Download: ML13333B240 (5) | |
Text
March 25, 1985 Docket No. 50-206 LS05-85-03-022 LICENSEE: Southern California Edison Company FACILITY:
San Onofre Nuclear Generating Station Unit No. 1
SUBJECT:
SUMMARY
OF MARCH 14, 1985 MEETING ON STEAM GENERATOR TUBE INSPECTION INTERVAL On March 14, 1985, members of the NRC staff and representatives of Southern California Edison Company met in Bethesda, Maryland. The purpose of the meeting was to discuss the licensee's reassessment of eddy current test results of the San Onofre Unit No. 1 steam generator tubes. A list of attendees is enclosed (Enclosure 1).
The agenda for the meeting is shown in Enclosure 2. Based on the reassess ment of the eddy current test results, the licensee has concluded that a conservative tube degradation rate (IGA) of 10% per refueling cycle operating interval can be assumed. Accordingly, the licensee plans to request that the NRC delete the current license condition that requires a steam generator tube inspection after six equivalent full power months and which was based on a higher degradation rate. The licensee would perform a steam generator tube inspection during the outage that is scheduled to begin on November 30, 1985 rather than during May 1985. The conclusions reached by the licensee are shown in Enclosure 3.
The Southern California Edison representatives stated that they plan to shut down May 3 for the steam generator tube inspection if the NRC disapproves the request to delete the current license condition. Accordingly, the licensee requested the staff's evaluation be completed by the middle of April.
The staff indicated that they would try to meet this schedule.
Walter A. Paulson, Project Manager Operating Reactors Branch #5 Division of Licensing
Enclosures:
- 1. List of Attendees
- 2. Agenda
- 3. Licensee conclusions cc w/nclosres:8503270459 850325 cc w/enclosures:
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March 25, 1985 cc Charles R. Kocher, Assistant Joseph 0. Ward, Chief General Counsel Radiological Health Branch James Beoletto, Esquire State Department of Health Southern California Edison Company Services Post Office Box 800 714 P Street, Office Bldg. 8 Rosemead, California 91770 Sacramento, California 95814 David R. Pigott Kenneth P. Baskin, Vice Orrick, Herrington & Sutcliffe President 600 Montgomery Street Nuclear Engineering San Francisco, California 94111 Licensing and Safety Department Southern California Edison Dr. Lou Bernath Company San Diego Gas & Electric Company 2244 Walnut Grove Avenue P. 0. Box 1831-Post Office Box 800 San Diego, California 92112 Rosemead, California 91770 Resident Inspector/San Onndre NPS c/o U.S.
NRC P. 0. Box 4329 San Clemente, California 92672 Mayor.
City of San Clemente San Clemente, California 92672 Chairman Board of Supervisors County of San Diego San Diego, California 92101 Director Energy Facilities Siting Division Energy Resources Conservation &
Development Commission 1516 - 9th Street Sacramento, California 95814 U.S. Environmental Protection Agency Region IX Office ATTN:
Regional Radiation Representative 215 Freemont Street San Francisco, California 94105 John B. Martin, Regional Administrator Nuclear Regulatory Commission, Pegion V 1450 Maria Lane Walnut Creek,. California 94596 MARCH 14, 1985 MEETING SOUTHERN CALIFORNIA EDISON COMPANY AND NRC STAFF ATTENDANCE LIST Name Affiliation W. Paulson NRC C. Y. Cheng NRC/MTEB Caius V. Dodd ORNL Bernard Turovlin NRC/MTEB H. F. Conrad NRC/MTEB C. N. Harberts Southern California Edison -
Station L. A. Bennett SCE -
Licensing B. L. Curtis SCE - Allen Nuc. Assoc.
B. D. Liaw NRC/MTEB NRC MEETING AGENDA DATE: MARCH 14, 1985 TIME:- 9:00 AM PLACE: PHILLIPS BLDG, BETHESDA, MD.
SUBJECT:
STEAM GENERATOR INSPECTION INTERVAL SAN ONDFRE UNIT 1
- 1. INTRODUCTION
- 2.
BACKGROUND AND METHODOLOGY
- a.
GENERAL
- b. BASIS FOR 1981 DEGRADATION RATE
- c.
1962 AND 1984 INSPECTION RESULTS
- d. OVERVIEW OF STEAM GENERATOR CHEMISTRY
- e.
RE-EVALUATION OF STEAM GENERATOR INSPECTION INTERVAL
- 3. CORRELATION OF ECT AND PULLED TUBE DATA
- 4. ASSESSMENT OF IGA PROGRESSION
- 5. CONCLUSIONS CONCLUSIONS
.CORRELATION OF 1980 ECT DATA WITH PULLED TUBE METALLURGICAL RESULTS CONFIRMS BOBBIN COIL DETECTABILITY OF IBA > 20%.
DETECTABILITY LEVEL AT SAN ONOFRE UNIT 1 IS CONSISTENT WITH THE COMMONLY ACCEPTED DETECTABILITY THRESHOLD OF 40% FOR IGA.
REVIEW OF HISTORICAL EDDY CURRENT INSPECTION DATA IDENTIFIES NON-SLEEVED TUBES AS COMPRISING AN "INACTIVE" REGION.
CONSIDERING THE PRESENCE OF NON-QUANTIFIABLE "IGA-LIKE" INDICATIONS IN CERTAIN NON-SLEEVED TUBES AND IN LIGHT OF THE
-40% DETECTABILITY -THRESHOLD, IT CAN BE ASSUMED THAT IGA HAS PROGRESSED TO LEVELS APPROACHING 40% IN NON-SLEEVED TUBES.
"ISA-LIKE" INDICATIONS.ARE PRESENT IN EARLIEST AVAILABLE I.E. 1973 -
SAN ONOFRE UNIT 1 EDDY CURRENT DATA, SUGGESTING THAT IGA COMMENCED SOMETIME PRIOR TO 1973.
CONSERVATIVELY ASSUMING 0X IGA LEVEL IN 1973 AND 40 IGA LEVEL IN i980- AN OPERATING PERIOD IN EXCESS OF 60 EFPM THEN A CONSERVATIVE DEGRADATION RATE OF 407.PER 60 EFPM CAN BE ASSUMED, EQUIVALENT TO A RATE OF 10% PER REFUELING CYCLE OPERATING INTERVAL OF 15 EFPM.
BASED ON THE CONSERVATIVELY ASSUMED LEVEL AND PROGRESSION RATE OF IGA' IN NON-SLEEVED TUBES, IT IS CONCLUDED THAT EDDY CURRENT INSPECTIONS AT REFUELING OUTAGE INTERVALS WILL DETECT IGA AT LEVELS CONSISTENT WITH THE REQUIREMENTS FOR TUBE REPAIR AT SAN ONOFRE UNIT 1.
IMPROVEMENTS IN STEAM GENEATOR CHEMISTRY PROCEDURES AND CON TROLS, DEMONSTRATED BY-OPERATING EXPERIENCE SINCE THE SLEEV REPAIR PROJECT, SUPPORT THE FINDINGS OF THE 1982 AND 1984.
EDDY CURRENT INSPECTIONS THAT SIGNIFICANT PROGRESSION OF IGA IN NON-SLEEVED TUBES IS NOT OCCURING.
CONTINUING MANAGEMENT COMMITMENT TO STRICT CHEMISTRY CON TROLS PROVIDES ASSURANCE THAT CONDITIONS WHICH COULD ACCELERATE THE IGA PROGRESSION RATE ARE NOT LIKELY TO OCCUR.
THE APPLICABILITY OF "LEAK BEFORE BREAK" ASSURES THAT.
POSTULATED ISOLATED ISOLATED INSTANCES OF HIGH LEVEL IGA IN NON-SLEEVED TUBES ARE NOT A SAFETY CONCERN.