05000267/LER-1980-064, Forwards LER 80-064/03L-0

Forwards LER 80-064/03L-0

ML19345C513
Person / Time
Site:	Fort Saint Vrain
Issue date:	11/26/1980
From:	Warembourg D PUBLIC SERVICE CO. OF COLORADO
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19345C514	List: 05000267/LER-1980-064, Forwards LER 80-064/03L-0 05000267/LER-1980-064-03, /03L-0:on 801103,diesel Engine 1B on Diesel Generator 1A Found to Have Inoperable Exhaust Temp Trip Circuit.Caused by Faulty Exhaust Temp Thermcouple. Thermocouple Replaced
References
P-80415, NUDOCS 8012050408
Download: ML19345C513 (5)

LER-1980-064, Forwards LER 80-064/03L-0

Event date:
Report date:
2671980064R00 - NRC Website

text

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7 Pubine scsice company or conomuIe i) 16805 ROAD 19%

_1w PLATTEVILLE, COLORADO 80651 November 26, 1980 Fort St. Vrain Unit No. 1 P-80415 Mr. Karl V. Seyfrit, Director Nuclear Regulatory Commission Region IV Of fice of Inspeccien and Enforcement 611 Ryan Plaza Drive Suite 1000 Arlington, Texas 76012

Reference:

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/

80-64, Final, submitted per the requirements of Technical Specification AC 7.5.2(b)2.

Also, please find enclosed one copy of the Licensee Event Report for Reportable Occurrence Report No. 50-267/80-64.

Very truly yours, t

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Don Warembourg Manager, Nuclear Production DW/cis Enclosure cc: Director, MIPC i

9 8012050 F 3

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REPORT DATE:

November 26, 1980 REPORTABLE OCCURRENCE 80-64 ISSUE O OCCURRENCE DATE:

November 3,1980 Page -1 of 4 i

FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE CCt4PANY OF COLORADO

- 16805 UELD COUNTY ROAD 19 1/2 PLATTEVILLE, COLCRADO 80651 l

I REPORT No. 50-267/80-64/03-L-0 Final IDENTIFICATION OF OCCURRENCE:

During regular surveillance testing,13 diesel engine of the LA standby generator unit f ailed to trip and declutch. This is interpreted as a de-graded mode of operation per LCO 4.6.1(d) and is reportable per Fort St.

Vrain Technical Specification AC 7.5.2(b)2.

EVENT

DESCRIPTION

On November 3,1980, with the plant at 50% thermal power and 134 Mh'L, plant operations personnel perf orming a routine surveillance test found 13 diesel engine, K-9204X, would not trip and declutch as required. Electrical mainte-nance personnel were called to investigate the problem and f ound the exhaust temperature thermocouple to. be f aulty.

(See Figure 1) ))During($)

normal diesel i

(

and

, with generator startup, exhaust temperature thermocouples,

({}and(

, detect the rise in engine ex-The trip circuit has a]) time delay of approximately temperature indicating switches, haust temperature.

30 seconds to allow the exhaust cam the setpoint If an engine, (]) or (f)perature to increase past of 175'F.

., does not start within this 30 second time period, the trip circuit will actuate and declutch the engine that f ailed to start so that it does not drag down the running engine. This trip circuit stays in eff ect, 'and if an engine should stop operating f or any reason, the trip circuit would again actuate and declutch the aff ected engine.

With the IB engine exhaust temperature thermocouple ([) inop erable, the 13 engine ([) would not have tripped and declutched if it f ailed to start.

This would drag down the operating diesel engine and =ake the diesel gener-ator set inoperable.

LA diesel engine ($) and 13 diesel engine ()) were operable at this time and did not prevent the use of 1A diesel geserator set ([). However, if the 13 diesel engine had failed to start, the failed exhaust temperature thermocouple would have prevented the engine frca declutching as required.

The 13 diesel generator unit was operable and available throughout this period. as indicated by successful surveillance tests.

+

REPORTABLE OCCURRE"CE 80-64 ISSUE O Page 3 of 4 Engine Exhaust Thermocouple T/C_

Start Engine Start Signal Temperature Indicating Switch TIS TD 30 Second Time Delay Energi::es Trip and a

Declutch Circuit I

lF Opens When Exhaust Normal Closed Opens Temperature Exceeds For 30 Seconds 175'F Te=perature Indicating Switch h-A Thermocouple <[- -- TIS -

IIS 3 Ther"occuple 4

8 W

____ 30 Second,,__ frip Cir-Time Delay Cir-cuit cuit i

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Engine 1A Generator 2ngine 13 N/d Y/' /b K-9203X K-9204X

, K-9201 O

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Clutch 1

FIGURE 1 i

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REPORTA3LE OCCURRENCE 30-64 ISSUE O 4

CAUSE,

DESCRIPTION

Inability to trip 'and declutch the IB diesel engine was caused by failure of the exhaust temperature ther=occuple. This failure caused' the temperature:

indicating switch to sense a high ' temperature and prevented proper operation

~

of the trip and declutch circuit.

j

. A'similar problem occurred' before and was reported as Abnormal Occurrence 75-08.

At that time, a program was initiated to replace these thermocouples

~

on a regular basis. This program is still being carried out..This particular thermocouple.vas put in. service September 3,,1930.

CORRECTIVE j

ACTION:

j The thermocouple was replaced and the surveillance test successfully completed.

This particular thermocouple f ailure does not appear to be generic in nature.

We will continue with the thermocouple replacement program and will make ad-l justments in this program, if necessary, depending en thermocouple failure rates.

No further corrective action is anticipated or required.

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REPORTABLE OCCURRENCE 80-64 ISSUE O Page 4 of 4 1

7 I

Prepared By:

Asa B. Reed

]

Technical Services Technician Reviewed 3y:

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._S j,y J. W. Ghhm J

Technic"al Services Supervisor 2

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Reviewed By:

41 Frank :1. Mathie i

4 Operations 'fanager A

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' cw C'df-% d <!etto Approved By:

Don Warenbourg XJ Manager, Nuclear Production l

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