ML13317A831
| ML13317A831 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 01/22/1982 |
| From: | Baskin K Southern California Edison Co |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8201260295 | |
| Download: ML13317A831 (6) | |
Text
Southern California Edison Company P. 0.
BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD, CALIFORNIA 91770 K. P. BASKIN TELEPHONE MANAGER OF NUCLEAR ENGINEERING, January 22, 1982 (213) 572-1401 SAFETY, AND LICENSING Director, Office of Nuclear Reactor Regulation Attention: D. M. Crutchfield, Chief Operating Reactors Branch No. 5 Division of Licensing 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
References:
- 1.
Steam Generator Repair Report Revision 1, San ofre uclear Generating Station, Unit 1, March 1981.
- 2. Letter SCE (Baskin) to NRC (Crutchfield), December 22, 1981.
- 3. Return to Power Report, Steam Generator Repair Program for San Onofre Nuclear Generating Station, Unit 1, April 1981.
In accordance with License Condition 3.E, San Onofre Unit 1 will be shut down within six effective full power months of operation from the start of Cycle 8 operation to perform an inspection designed to monitor the effectiveness of the 1980-1981 steam generator repair program. This letter sets forth the inspection program which is required to be submitted to the Nuclear Regulatory Commission at least forty-five days prior to the scheduled shutdown by License Condition 3.E. Although it is anticipated that six equivalent months of operation will be achieved in May 1982, this shutdown may occur as early as March 1982 due to plant modification considerations. If an early shutdown occurs, it is anticipated that four to four and one-half equivalent months of operation will be achieved at the time of the shutdown.
Additionally, as noted in Reference 2, we are not planning a complete technical specification inspection for this outage.
An overview of the steam generator inspection program is provided in Enclosure (1).
Enclosures (2) and (3) provide detailed descriptions of the 400I 9201260295 820122 PDR ADOCK 05000206 a
(
Mr. D. M. Crutchfield
-2 eddy current testing and pressure testing programs. Prior to our return to power from this inspecton outage, a complete report on our findings and corrective measures will be provided.
If you should have any questions or desire further information concerning the enclosures, please let me know.
Very truly yours, Enclosures cc:
R. H. Engelken, Director, OIE, Region V, USNRC L. Miller, USNRC, Resident Inspector
.0 ENCLOSURE (1)
STEAM GENEPAIOR GENERAL OUTAGE PLAN
- 1.
Primary-Secondary Differential Pressure Test of U-tube Bundle
- 2.
Cold Secondary Side Leakage Test
- 3.
Eddy Current Testing of Steam Generator.Tubes
- a.
General surveillance of tubes/sleeves
- b.
Leader-tube inspection
- 4.
Ultrasonic Testing of Steam Generator Sleeves
- a.
Leader-tube inspection
- 5.
Steam Generator Evaluation/Repair
- a.
Data Evaluation
- b. Tube Reroval and Evaluation (if required)
- c.
Plugging (If required)
- d.
Individual Tube Pressure Testing (if required)
- 6.
Cold Secondary Side Leakage Test (if required)
ENCLOSURE (2)
EDDY CURRENT INSPECTION PIGAM Inside the 1980-1981 Repair Boundary Within the sleeving repair boundary described in Reference (1) approximately 10% of the sleeved tubes will be inspected from the hot leg side through the first.support plate.
The inspection pattern can generally be described as a three-by-three matrix adjusted, as neces sary, to insure a representative number of all types of sleeve joints are sampled.
This inspection will be performed using a magnetically biased conventional probe with multifrequency techniques and compared with the baseline inspection conducted in May 1981.
Sleeves exhibiting significant deviations from the baseline data will be evaluated further on a case by case basis.
Expansion of the basic inspection program will depend on the nature and extent of any sleeve imperfections identified.
Plugging criteria will be that of the Appendix A Technical Specifications.
Leader-Follower Program As noted in Reference (1),
in the reference upper joint, conven tional eddy current techniques will not, by themselves, provide adequate monitoring of the integrity of the joint.
Therefore, the leader-fol lower program was included.
During this inspection, all leader and follower tubes will, also, be inspected using the ultrasonic process previously described in Reference (1).
Should either the eddy current or ultrasonic process indicate this joint has significantly degraded in any of the leader or follower tubes, a specimen will be removed for metallurgical evaluation.
The results of this evaluation and any corrective measures undertaken will be forwarded for your review prior to our return to power.
Outside the 1980-1981 Repair Boundary Outside the 1980-1981 repair boundary, approximately 20% of the.
tubes in each steam generator will be inspected from the hot leg side through the first support plate.
The inspection program will consist of all unsleeved tubes within 2 tubes of the repair boundary and a four-by four inspection pattern throughout the remainder of the periphery.
These tubes will be inspected with a multi-coil surface riding probe, known as a "four by four probe", utilizing multifrequency techniques.
This probe consists of upper and lower sets of four series-wound surface riding coils.
Each set produces absolute signals which may then be differentially analyzed.
This probe is as effective as the previously used rotating pancake coil (RPC) in detecting attack of the IGA type at the top of the tubesheet.
In the periphery, the plugging criteria will be consistent with that used to establish the original sleeving boundary (Reference 3).
Specifically, all tubes with detectable IGA indications at the top of the tube sheet will be plugged.
In addition, any unsleeved
Enclosure (2)
Eddy Current Inspection Program Cont'd....
tube immediately adjacent to a tube with an IGA indication greater than or equal to 50% will be plugged.
The inspection will be expanded to surround any pluggable tube until one tube without detectable IGA is found.
These plugging and program expansion criterion may be reeval uated if the multi-coil probe is found to be significantly more sen sitive to IGA than the RPC probe.
Of course, should changes in the plugging criteria be considered, you will be notified.
ENCLOSURE (3)
PRESSURE TESTING PROGRAM In addition to the eddy current and ultrasonic inspections noted in Enclosures 1 & 2, a primary-to-secondary differential pressure test at 1900 psid will be performed at the beginning of the outage.
This test will demonstrate margin to normal operating conditions for the entire tube bundle including the reference upper sleeve joint. Fbllowing this test, a secondary side leakage test at 800 psig will be performed to identify leaking tubes.
All leaking tubes will be plugged prior to return to power.
Should any leaking tubes be identified outside the 1980-1981 repair boundary, a program to individually pressure test a sample of the accessible leaking tubes will be implemented.