ML13308B437
| ML13308B437 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 03/22/1978 |
| From: | Head J SOUTHERN CALIFORNIA EDISON CO. |
| To: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| IEB-78-02, IEB-78-2, NUDOCS 8102190185 | |
| Download: ML13308B437 (2) | |
Text
L Southern California Edison Company P. 0. BOX 800 2244 WALNUT GROVE AVENUE J. T. HEAD, JR.
ROSEMEAD, CALIFORNIA 91770 TELEPHONE VICZ PRESIDENT 213-572-1472 March 22, 1978 U
U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement Region V Suite 202, Walnut Creek Plaza 1990 North California Boulevard Walnut Creek, California 94596 Docket No. 50-206 San Onofre Unit 1 Attention:
Mr. R. H. Engelken, Director Re:
Supplemental Information IE Bulletin No. 78-02 Tlerminal Block Qualification
Dear Sir:
Reference is made to your correspondence of January 30, 1978, forwarding the subject IE Bulletin and our response to this Bulletin dated February 8, 1978.
IE Bulletin 78-02 discussed potential problems with unprotected terminal blocks inside the containment which must function in a post-accident environment.
As stated in our response dated February 8, 1978, there are no such unprotected terminal blocks at San Onofre Unit 1.
Subsequent investigation has revealed, however, that post-accident environmental qualification documentation does not exist for the terminal boxes used in conjucntion with two electrical penetrations designated EPC-23 and WPC-23.
An analysis of circuits utilizing these terminal blocks was conducted.
It was determined that the circuits of components utilizing these terminal blocks and required to function in the post-accident environment are de-energized in order to place the component in the appropriate posture for accident mitigation.
C Any credible fault postulated to occur at the terminal block as a result of post accident environmental conditions would not prevent the affected component from assuming its appropriate de-energized position for accident mitigation.
There fore, it is concluded that the referenced qualification is not required for the subject terminal boxes since their failure does not present a hazard to the safe operation of San Onofre Unit 1.
Should you have any further questions regarding this item, please contact me.
Sincerely, I
-l cc: Director, Office of Nuclear Reactor Regulation, USNRC Director of Reactor Operations Inspection, USNRC