ML20041C319

Forwards LER 82-002/03L-0.Detailed Event Analysis Encl

ML20041C319
Person / Time
Site:	Fort Saint Vrain
Issue date:	02/19/1982
From:	Warembourg D PUBLIC SERVICE CO. OF COLORADO
To:	Jay Collins NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20041C320	List: ML20041C319 ML20041C323
References
P-82045, NUDOCS 8203010160
Download: ML20041C319 (5)

Text

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public service company ce ceawado l l 5 Road 19 1/2, Platteville, Colorado 80651-9298 .l i  !

1 BECEWN  !

February 19, 1982 '

s FEB2 G19ggy.im unrW"# Fort St. Vrain Unit No.; 1 -

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g 508 $i$ I P-82045 @)Il - ' ' fi$ - \n J V Q

^ w FEB 2 21982 1 " S j Mr. John T. Collins, Regional Administrator Region IV-Nuclear Regulatory Commission 611 Ryan Plaza Drive '

1 Suite 1000 Arlington, Texas 76011 l

Reference:

Facility Operating License ,

No. DPR-34 Docket No. 50-267

Dear Mr. Collins:

Enclosed please find a copy of Reportable Occurrence Report No. 50-267/82-002, Final, submitted per the requirements of Technical Specification AC 7.5.2(b)1.

Also, please find enclosed one copy of the Licensee Event Report for i Reportable Occurrence Report No. 50-267/82-002.

i Very truly yours, h W(ts<dn Don Warembourg Manager, Nuclear Production DW/cis ,: (

4 Enclosure -+ -,

cc: Director, MIPC _ [,

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4 4 8203010160 820219 i

PDR ADOCK 05000267 S PDR I

REPORT DATE: February '.9. 1982 REPORTABLE OCCURRENCE 82-002 ISSUE O OCCURRENCE DATE: January 21, 1982 Page 1 of 4 FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO 16805 WELD COUNTY ROAD 19 1/2 PLATTEVILLE, COLORADO 80651-9298 REPORT NO. 50-267/82-002/03-L-0 Final IDENTIFICATION OF OCCURRENCE:

On January 21, 1982, while the reactor was shutdown, plant instrumentation technicians performing scheduled Surveillance Tests found three " loss of bearing water" differential pressure switches with setpoints less conservative than required by Fort St. Vrain Technical Specification LCO 4.4.1.

This is reportable per Fort St. Vrain Technical Specification AC 7.5.2(b)1.

EVENT DESCRIPTION:

During scheduled Surveillance Testing, differential pressure switches PDIS-21180, PDIS-21182, and PDIS-21184 used to monitor the pressurt differential between the bearing water cavity and main drain of 10 helium circulator (C-2104) were found to trip at 340 psid, 465 psid, l and 360 psid, respectively. These trip points are below the Technical Specification LCO limit of greater than or equal to 475 psid.

l Referring to Figure 1, as the pressure differential between the water supply cavity and main drain ecreases, the pressure differential indicating switches (PDIS) I will individually close at their respective setpoin+s. This applies a voltage to the s'vi tch input modules (XDIS) 2 , tripping them. Each tripped X IS module transmits a signal to both "A" and "B" logic channels 3 . When either "A" or "B" AND logics receive inputs from any two of the three .

l XDIS m dules, they will transmit a signal to the "A" or "B" logic OR gate 4 , respectively. The OR gates tra smit any input signal to the respective special control relay (XCR) 5 to energize auxiliary relays to trip the circulator.

l l

Even though the "as found" trip points were less conservative than the Technical Specification LCO limit, the out-of-tolerance condition of the PDIS's would not have prevented them from fulfilling their design function.

REPORTABLE OCCURRENCE 82-002 ISSUE O Page 2 of 4 CAUSE DESCRIPTION:

Instrumentation personnel determined that instrumentation setpoint drift was the immediate cause of the occurrence.

CORRECTIVE ACTION:

The pressur differential switches were calibrated to acceptable setpoints.

No further corrective action is anticipated or required.

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. i REPORTABLE OCCURRDiCE 82-002 ISSLT O '

Page 3 of 4

Channel A Channel B Channel C PDIS PDIS P O

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@ XDIS XDIS XDIS i

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@ "A" Logic "B" Logic j 2/3 2/3 I

/ From Other Circulator N N Trip Parameters '

a l "A" Logic "B" Logic b

OR Gate OR Gate 1

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@ XCR , XCR "A" "B"  ;

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3 1

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• i Circulator Circulator Auxiliary Auxiliary

System Relays System Relays FIGURE 1 l

s REPORTABLE OCCURRENCE 82-002 ISSUE O Page 4 of 4 Prepared By: 11 h k ,

Paul A. Tramp I -

Technical Services Technician Reviewed By: [bl Charles Fuller-d Technical Serv es E 1 ering Supervisor

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Reviewed By:

EdwidN.M11'l

Station Manager Approved By: / 'M tewdwu, Don Warembourg /

Manager, Nuclear Production L

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