ML19210E315

Forwards LER 79-052/03L-0

ML19210E315
Person / Time
Site:	Fort Saint Vrain
Issue date:	11/20/1979
From:	Warembourg D PUBLIC SERVICE CO. OF COLORADO
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19210E316	List: ML19210E315 ML19210E320
References
P-79278, NUDOCS 7912040326
Download: ML19210E315 (4)

Text

. .

4 Public service company e conendo 16805 Weld County Road 19 1/., Platteville, Colorado 80651 November 20, 1979 Fort St. Vrain Unit No. 1 P-79278 Mr. Karl V. Seyfrit, Director Nuclear Regulatory Coc: mission Region IV Office of Inspection and Enforcement 611 Ryan Plaza Drive Suite 1000 Arlington, Texas 76012 REF: Facility Operating License No. DPR-34 Docket No. 50-267

Dear Mr. Seyfrit:

Enclosed please find a copy of Reportable Occurrence Report No. 50-267/

79-52/03-L-0, Final, submitted per the requirements of Technical Specifi-cation AC 7.5.2(b)4.

Also, please find enclosed one copy of the Licensee Event Report for Reportable Occurrence Report No. 50-267/79-52/03-L-0.

Very truly yours, Don Warembourg Manager, Nuclear Production DW/cls cc: Director, MIPC

. 1472 '24 $[

7912040 N /[

REPORT DATE: Novembe r 20. 1979 REPORTABLE OCCURRENCE 79-52 ISSUE O OCCURRENCE DATE: October 22. 1979 Page 1 of 3 FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO 16805 WELD COUNTY ROAD 191/2 PLATTEVILLE, COLORADO 80651 REPORT NO. 50-267/ 79-5 2/03-L-0 Final IDENTIFICATION OF OCCURRENCE:

On October 22, 1979, with the plant operating at approximately 9% power and "A" instrument air compressor out of service for maintenance, "B" instrument air compressor was found to have insufficient output.

This constitutes operation under a degraded mode of LCO 4.3.6 and is reportable per Fort St. Vrain Technical Specification AC 7.5.2(b)2.

EVENT DESCRIPTION:

At approximately 0900 hours0.0104 days <br />0.25 hours <br />0.00149 weeks <br />3.4245e-4 months <br /> on October 22, 1979, with the plant operating at approximately 9% thermal power, "A" instrument au compressor was removed from service in order to repair the manual trip mechanism on its safety relief valve.

Shortly thereaf ter, "B" instrument air compressor was determined to be providing insufficient output and the servics air system backup air supply was required.

The valve repair on "A" instrument air compressor was completed and the compressor returned to service shortly af ter 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> on October 22, 1979.

On October 23, 1979, with both "A" and "C" instrument air compressors operable, a capacity check of "B" comp:;essor indicated its output was less than the mini-mum required for operability.

Technical Specification LCO 4.3.6, Instrument Air System, indicates that the plant is not to be operated at power unless two of the three instrument air compressors are operable. Thus, the period of time with "A" compressor out of service and "B" compressor providing insufficient output constitutes operation in a degraded mode of LCO 4.3.6.

CAUSE DESCRIPTION:

Following the discovery that the instrument air compressor was not providing sufficient output, a quarterly preventive maintenance and inspection procedure was performed to investigate the cause of compressor inoperability.

f 1472 23

REPORTABLE OCCURRENCE 79-52 ISSUE O Page 2 of 3 CAUSE DESCRIPTION (Cont'd):

As a result of the inspection, a bent piston rod was discovered. Because of this, the piston did not sit properly in the cylinder. The output of the com-pressor was adversely affected by these factors, such that the compressor was not operating at its most efficient level.

CORRECTIVE ACTION:

In order to comply with Technical Specificaton requirement for two operable instrument air compressors, the "A" compressor was returned to service af ter discovery that "B" compressor was providing insufficient output.

The bent piston rod was replaced. A cracked piston and four discharge valves were replaced, and four intake valves were rebuilt during the quarterly inspection.

A capacity check upon completion of the repair indicated that the compressor was once again providing sufficient output, and the compressor was returned to service.

No further corrective action is anticipated or required.

1472 26

. REPORTABLE OCCURRENCE 79-52 ISSUE O Page 3 of 3 Prepared by: _v Cathy CQlirsch d' Technical Services Technician Reviewed by: u' 0' i >

J.' W. Gahm

. Technical Services Supervisor Reviewed by:

Frank M. Mathie Operations Manager Approved by: Wm ,

Don Warembourg g Manager, Nuclear Production 1472 27

.