05000206/LER-1979-024, Forwards LER 79-024/03L-0

Forwards LER 79-024/03L-0

ML13330A843
Person / Time
Site:	San Onofre
Issue date:	01/31/1980
From:	Ottoson H SOUTHERN CALIFORNIA EDISON CO.
To:	Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
Shared Package
ML13330A844	List: 05000206/LER-1979-024, Forwards LER 79-024/03L-0 05000206/LER-1979-024-03, /03L-0:on 791203,during Normal Operations,Mods Involving Instrumentation on Feedwater Flow Orifices & Steam Generator hi-lo Level Alarms Discovered Made W/O Approved Design Change.Caused by Failure to Follow Procedure
References
NUDOCS 8002040466
Download: ML13330A843 (2)

LER-1979-024, Forwards LER 79-024/03L-0

Event date:
Report date:
2061979024R00 - NRC Website

text

Southern California Edison Company C

P.O. BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD, CALIFORNIA 91770 January 31, 1980 U. S. Nuclear Regulatory Comission Region V Office of Inspection and Enforcement Suite 202, Walnut Creek Plaza 1990 North California Boulevard Walnut Creek, California 94596 Attention:

Mr. R. H. Engelken, Director Docket No. 50-206 San Onofre - Unit 1

Dear Sir:

This letter describes a reportable occurrence involving modifications to plant equipment which were performed without an approved design change.

Submittal is in accordance with the reporting requirements stipulated in Section 6.9.2.b.3 of Appendix A to the Provisional Operating License DPR-13.

The item was judged to be not reportable initially; however, subsequent review has concluded that the incident is reportable under the requirements of 6.9.2.b.3.

On December 3, 1979, station personnel discovered that a digital dif ferential pressure meter utilizing the main feedwater flow orifices had been installed without an approved design change.

Subsequently an investi gation was initiated by the station to disclose any additional nodifications to plant equipnent that could have been performed without the appropriate design review.

One additional instance concerning the steam generator Hi-to level alarm was disclosed.

A discussion with plant instrumentation personnel indicated that the digital meter was tenporarily installed in parallel with the existing dif ferential pressure instruments on a trial basis and was not intended for operational use.

The purpose of the installation was to investigate a possible method of improving the accuracy of feedwater flow measurement.

The meter has been disconnected from the flow orifices until an approved design change is issued.

8002040

U. S. Nuclear Regulatory Commission Page 2 The steam generator Hi-Lo level alarm modification involved the transfer of the alarm function fran the narrcw range level recorders to a set of bistable amplifiers.

The mercury switches which originally provided the alarm signal were furnished as an integral part of the level recorders.

Whenever a narrow range recorder was removed for main tenance, the steam generator level indication and the Hi-Io alarm were defeated.

The installation of the bistables ensured that the Hi-Lo alarm would be available to the operators during recorder maintenance.

A design change will be prepared to document the engineering review of the bistable installation.

To prevent recurrence of this event, station supervisory and engineering personnel will receive further instruction in the requirements of our design control procedures.

This instruction will be completed prior to the refueling outage scheduled for April of this year.

A review of our administrative con trols over design indicates that no procedural modifications are required.

The subject equipment modifications were intended to improve the reli ability and function of the affected systems.

A review of the modifications indicated that there was no significant effect on plant safety.

No addi tional events of this type were identified during the station's investigation.

Should you have any questions regarding this matter, please contact me.

Sincerely, H. L. Ottoson Manager, Nuclear Generation

Attachment:

Licensee Event Report 79-024 17A or, Nuclear Reactor Regulation (30)

Director, Office of Management Information & Program Control (3)

Director, Nuclear Safety Analysis Center (1)