ML13317A629
| ML13317A629 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 06/08/1981 |
| From: | Moody W SOUTHERN CALIFORNIA EDISON CO. |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8106150302 | |
| Download: ML13317A629 (2) | |
Text
Southern California Edison Compan P. 0. BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD, CALIFORNIA 91770 T
H W. C. MOODY TELEPHONES MANAGER, NUCLEAR LICENSING (213) 572-1817 (213) 572-1806 June 8, 1981 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 Flooding from Non-Safety Related Piping and Equipment San Onofre Nuclear Generating Station Unit 1
References:
- 1. Letter, D. M. Crutchfield, NRC, to Robert Dietch, SCE, Multi-Plant Issue B-11 and Partial Review of SEP Topics III.5.b and VI.7.d, March 18, 1981
- 2. Letter, K. P. Baskin, SCE, to D. M. Crutchfield, NRC, Effects of Non-Category A Equipment Failure, August 29, 1980
- 3. Letter, K. P. Baskin, SCE, to 0. M. Crutchfield, NRC, Flooding from Non-Safety Related Piping and Equipment, October 15, 1980
- 4. Letter, K. P. Baskin, SCE, to 0. M. Crutchfield, NRC, SEP Topic 111-6, Seismic Design Considerations, April 24, 1981 Your letter of March 18, 1981 (Reference 1) transmitted to us your Technical Evaluation Report (TER) concerning the susceptibility of safety related systems to flooding from failure of non-Category A systems for San Onofre Unit 1. The purpose of this letter is to provide updated information with respect to our plans to implement two plant modifications reflected in the TER:
circulating water line expansion bellows sleeves and any seismic upgrading of the Condensate Storage Tank (CST).
The TER approved our proposed plant modifications to mitigate the consequences of a postulated failure of the circulating water line expansion bellows. Reference 2 committed to install by June 1, 1981, flow restricting S
(The sleeve design was submitted by Reference 3.)
However, as discussed with your staff, the sleeves will not be installed until July 1, 1981 for the following reasons:
8106c1503o p
D. M. Crutchfield, Chief June 8, 1981
- 1.
Each bellows has a distinct difference pertaining to the retaining glands and mounting flanges.
- 2.
The guides for the retaining straps were not welded in the shop, necessitating additional field welding.
- 3.
Clips which were to be attached to the retaining straps were not welded on at the fabricators so additional field welding is necessary.
- 4.
The original date was based upon NRC approval of the design about January 1, 1981.
However, the TER was not issued until March 18, 1981.
With regard to the seismic reevaluation of the CST, our letter of August 29, 1980 indicated this would be completed by June 1, 1981.
This was based on the assumption that this tank would be included in the reevaluation of structures, the schedule for which was provided by our letter of April 24, 1981 (Reference 4).
However, as has been discussed with your staff, the CST is not being reevaluated as part of the structures reevaluation program, but is included in the reevaluation of mechanical piping and equipment. It is now expected that the CST will be reevaluated by approximately March, 1982.
Any modifications to the tank which may be required will be implemented after the Systematic Evaluation Program integrated assessment which is currently scheduled for April 30, 1982. In the meantime, as described on page 10 of the TER, the door between the CST and the +20' level of the turbine building has been replaced with a metal door with no windows or air ventilation. This door will be locked closed during power operation.
If you have any questions or comments, please let me know.
Very truly yours,