ML20212G561
| ML20212G561 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 09/24/1999 |
| From: | Scherer A SOUTHERN CALIFORNIA EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-97-01, TAC-M98593, TAC-M98594, NUDOCS 9909300037 | |
| Download: ML20212G561 (2) | |
Text
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SOUlHERN CALIIORNI A -
A. Edward Scherer a
EDISON 1"3"%,am, An HMSON MMWWOW Company i
September 24, 1999 j
U.S. Nuclear Regulatory Commission 4
Attention:' Document Control Desk l
Washington, D.C. 20555
Subject:
' Docket Nos. 50-361 and 50-362 Inspection Planning Update Regarding Generic Letter 97-01: " Degradation of Control Rod Drive Mechanism Nozzle and Other Vessel Head Penetrations" (TAC Nos. M98593 and M98594)
. San Onofre Nuclear Generating Station, Units 2 and 3
Reference:
Letter from A. E. Scherer (SCE) to the Document Control Desk (NRC),
dated January 13,1999; Request for Additional Information Regarding Generic Letter 97-01: " Degradation of Control Rod Drive Mechanism Nozzle and Other Vessel Head Penetrations," (TAC Nos. M98593 and M98594) San Onofre Nuclear Generating Station, Units 2 and 3 Gentlemen:
)
i The Southern California Edison Company (SCE) committed in the referenced letter to I
keep the NRC informed of future plans for eddy current examinations of the reactor vessel head penetrations at the San Onofre Nuclear Generating Station (SONGS),
Unit 3. ' This letter is to inform the NRC that SCE remains committed to performing eddy L current examinations of 100% of the reactor vessel head penetrations at San Onofre Unit 3; however, these examinations will not be performed during the Cycle 11 refueling outage.-
T lD As previously documented in the referenced letter, SCE continues to beliave that the timing of the examinations should meet several objectives. Primarily, the timing of the examinations must help ensure reactor safety. Also, SCE feels that the timing should maximize, as much as reasonably possible, the chances of detecting any degradation prior to the need for a repair method that would require welding. Finally, and within the bounds of the first two objectives, SCE believes that it would be advantageous to develop and apply an effective mitigation strategy to reduce or eliminate the need for 3g lature examinations.
T4 9909300037 990924 J
PDR ADOCK 05000364 P
N-P. O. Box 128 :
San Clememe. CA 92674-0128 949-368 7501' 1
- Fax 949 368 7575 4
a
Also, SCE continues to believe that the following reasons indicate that it is not imperative that eddy current examinations be performed during the Unit 3 Cycle 11 refueling outage:
1.
The EPRI model places all plants in three categories based on the time remaining to reach the NEl benchmark crack depth:
e less than 5 years from 1/1/97.
between 5 and 15 years from 1/1/97 (SONGS 3 is in this category).
e greater than 15 years from 1/1/97 (SONGS 2 is in this category).
e The EPRI model runs completed to date indicate that SONGS 3 will not t
experience cracking which would exceed the NEl benchmark crack depth prior to 1/1/2002 (i.e., five years after 1/1/97).
2.
SCE believer that delaying the examination does not constitute a safety risk.
SCE will continue to:
1) maintain the commitment to perform eddy current examinations of 100%
of the reactor vessel head penetrations at San Onofre Unit 3 at a time that meets the objectives stated above, 1
2) perform visual inspections of the periphery reactor vessel head penetration nozzles during each refueling outage for both Units 2 and 3, 3) keep the NRC informed of the future plans for eddy current examinations at Unit 3 on a cycle by cycle basis, a l
4) work toward the development of a r,..q bn technique.
If you have any questions or would like additional information regarding this issue, please contact me or Mr. Jack Rainsberry at (949)368-7420.
l i
l Sincerely, 4
i cc:
E. W. Merschoff, Regional Administrator, NRC Region IV J. A. Sloan, NRC Senior Resident inspector, San Onofre Units 2 & 3 L. Raghavan NRC Project Manager, San Onofre Units 2 and 3
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