05000206/LER-1981-006, Forwards LER 81-006/01T-0.Detailed Event Analysis Also Submitted

Forwards LER 81-006/01T-0.Detailed Event Analysis Also Submitted

ML14133A354
Person / Time
Site:	San Onofre
Issue date:	05/18/1981
From:	Haynes J SOUTHERN CALIFORNIA EDISON CO.
To:	Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML13333A746	List: 05000206/LER-1981-006, Forwards LER 81-006/01T-0.Detailed Event Analysis Also Submitted 05000206/LER-1981-006-01, /01T-0:on 810428,determined That Terminal Blocks Could Not Be Guaranteed to Function in post-accident Environ.Qualified in-line Splices in safety-related Circuits Will Be Installed on Terminal Blocks
References
NUDOCS 8106010452
Download: ML14133A354 (1)

LER-1981-006, Forwards LER 81-006/01T-0.Detailed Event Analysis Also Submitted

Event date:
Report date:
2061981006R00 - NRC Website

text

Southern California Edison Company P.O. BOX 800 7

2244 WALNUT GROVE AVENUE ROSEMEAD. CALIFORNIA 91770 AT J. G.HAYNESTEPHN MANAGER OF NUCLEAR OPERATIONS May 18, 1981(213) 5721742 U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement Region V 1990 North California Boulevard Suite 202, Walnut Creek Plaza Walnut Creek, California 94596 Attention: Mr. R. H. Engelken, Director DOCKET NO. 50-206 SAN ONOFRE - UNIT 1

Dear Sir:

By letter dated April 28, 1981, we provided written, prompt notification of a reportable occurrence involving the terminal blocks inside containment in safety related circuits. This letter provides the two week followup report and the licensee event report (LER No.81-006) in accordance with Specification 6.9.2.a of the San Onofre Unit 1 Technical Specifications.

Our evaluation of information obtained since our October 31, 1980 submittal, concerning the terminal blocks located inside containment, including the tests documented in the Sandia Report, NUREG/CR-1682, Electrical Insulators in a Reactor Accident Environment, concludes that operability of the terminal blocks in the post-accident environment cannot be assured and that replacement of safety related circuits on the terminal blocks with qualified in-line splices is warranted.

The terminal blocks in question appear to be made of a general purpose phenolic material.

As discussed in our April 28, 1981 letter, the replacement of the safety related circuits on the terminal blocks will be completed prior to startup of the unit from the current outage. Eleven components have been identified with safety related circuits utilizing terminal blocks, and qualified in-line splices are being installed.

If you have any questions regarding this matter, please let me know.

Very truly yours, Enclosure cc:

Director, Office of Management and Information Program Control (2)

D. M. Crutchfield, Chief, Operating Reactors Branch No. 5, DOL