ML13330B133
| ML13330B133 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 11/05/1986 |
| From: | Medford M Southern California Edison Co |
| To: | Lear G Office of Nuclear Reactor Regulation |
| References | |
| TAC-59406 NUDOCS 8611130357 | |
| Download: ML13330B133 (2) | |
Text
Southem California Edison Company P. 0.
BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD, CALIFORNIA 91770 M. O.MEDFORD TELEPHONE MANAGER OF NUCLEAR ENGINEERING November 5, 1986 (818) 302-1749 AND LICENSING Director, Office of Nuclear Reactor Regulation Attention:
Mr. George E. Lear PWR Project Directorate No. 1 Division of PWR Licensing-A U. S. Nuclear Regulatory Commission Washington, D.C.
20555 Gentlemen:
Subject:
Docket No. 50-206 Steam Generator Tube Inspections San Onofre Nuclear Generating Station Unit 1
Reference:
Letter Richard F. Dudley, NRC, to Kenneth P. Baskin, SCE, Review of License Condition Steam Generator Inspection Report, June 27, 1986 In accordance with Technical Specification 4.16 of Appendix A to Provisional Operating License DPR-13, Southern California Edison is planning to perform an inspection of the San Onofre Unit 1 steam generators during the refueling outage that is scheduled to begin June 1988. This letter transmits the portion of the inspection program requested by the referenced letter.
The enclosed plan incorporates the limited steam generator operating information available at this early date in Cycle 9 operation. As previously discussed with the NRC staff, there is a high probability that this plan will change as information on steam generator operation, eddy current technology improvements, and data comparisons are obtained. In addition, SCE plans to inspect the cold leg, top of the tubesheet region that, based upon the last technical specification inspection, is an area that merits attention during the upcoming inspection.
If you should have any questions or desire further information concerning the enclosure, please let me know.
Very truly yours, Enclosures cc:
J. B. Martin, Regional Administrator, Region V F. R. Huey, Senior Resident Inspector, Units 1, 2 and 3 8611130357 861105 PDR ADOCK o5000206 PDR_
ENCLOSURE Non-Sleeved Hot-Leg Side Eddy Current Inspection Program For the Cycle 10 Refueling Outage San Onofre Nuclear Generating Station, Unit 1
- 1. Eddy Current Inspection Approximately 30% (388) of the non-sleeved tubes in steam generator "C" will be inspected from the hot leg side to just below the first tube support plate. Only "C" steam generator will be inspected since the results of previous inspections have indicated that all steam generator tubing in this area is performing in a like manner.
The inspection program will consist of all non-sleeved tubes within two tubes of the sleeving repair boundary and one tube in each four-by-four pattern throughout the remainder of the periphery. This program will be conducted utilizing the latest eddy current equipment available to the industry. Data will be collected using a MIZ-18 digital data collection system and analyzed with the DDA-4 digital analysis system.
Each tube will be inspected with two different probes, the standard bobbin coil and the 8x1 probe. The bobbin coil inspection will be conducted utilizing the following frequencies:
400 KHz, 340 KHz, 100 KHz, and 10 KHz.
Each frequency will be generated in the differential and absolute modes. The 8x1 inspection will utilize two separate frequencies (300 KHz and 100 KHz), which provides the capability to mix out the tubesheet entry signal.
- 2. Analysis, Expansion, and Repair Criteria Information gathered from the bobbin coil and 8x1 probes will allow correlation to previous inspection data to further assess the IGA progression rate in the non-sleeved region. In addition, any indications that appear to be new or have apparent greater than 10 percent growth will be compared to previous eddy current signals to determine if this growth is real or apparent. Tube sample removal and destructive analysis or the use of advanced nondestructive testing technologies (e.g.,
ultrasonic testing or rotating pancake coil eddy current probes) will be considered for use if there are indications of real growth and the cause of the growth is not readily discernible.
All data generated in this inspection will be evaluated using the DDA-4 digital data analysis system.
Any tube identified with an IGA indication greater than or equal to 50%
will be plugged and the inspection program will be expanded at least two tube pitches (24 tubes) surrounding the pluggable tube to determine if other pluggable IGA indications exist. In addition, the inspection will be expanded to the other two steam generators in accordance with the technical specifications.
LBennett:7534F