ML19260D560

Forwards LER 80-002/03L-0

ML19260D560
Person / Time
Site:	Fort Saint Vrain
Issue date:	02/05/1980
From:	Warembourg D PUBLIC SERVICE CO. OF COLORADO
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19260D561	List: ML19260D560 ML19260D567
References
P-80015, NUDOCS 8002110417
Download: ML19260D560 (4)

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..w g pubne service company ce Ock ele 16805 Weld County Road 19 1/2, Platteville, Colorado 80651 Februarf 5,1980 Fort S t. Vrain Uni t No . 1 P-80015 Mr. Karl V. Seyfrit, Director Nuclear Regulator / Commission Region IV Office of Inspection and Enforcement 611 Ryan Plaza Drive Suite 1000 Arlington, Texas 76012 Refe rence : Facility Operating License No. DPR-34 Docket No. 50-267

Dear Mr. Seyfrit:

Enclosed please find a copy of Reportable occurrence Report No. 50-267/80-02, Final, submitted per the requirements of Technical Specifi-cation AC 7.5.2(b)2.

Also, please find enclosed one copy of the Licensee Event Report for Reportable Occurrence Report No. 50-267/90-02.

Ve ry truly yours ,

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/W u m' Don Warembourg /

Manager, Nuclear Production DW/cis *O'i , , ()

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Enclosure cc: Director, MIPC seY 6

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REPORT DATE: Februarv 5, 1980 REPORTABLE OCCURRCICE 80-02 ISSUE 0 GCCURRENCE DATE: (De te rmine d) Janua rv 7, 1980 Page 1 of 3 FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO 16805 WELD COUNTY ROAD 191/2 PLATTZVILLE, COLORADO 80651 REPORT No. 50- 26 7/ 80-02/03-L-0 FINAL IDENTIFICATION OF UCCURRENCE :

On January 7,1980, it was determined that the startup channel scram pro-tection at i 105 cps was not operable during the installation of region cons traint devices. This scram p rotection is required by LCO 4.4.1, Table 4.4-1,except when the reactor mode switch is in the "Run" position.

This is reportable per Fort St. Vrain Technical Specification AC 7.5.2(b)2.

EVENT DESCRIPTION:

On January 7,1980, with the reactor operating at less than 2 rated thermal power, it was determined that the region constraint device installation had been performed with the i 105 cps startup channel scram protection inoperable.

As noted in FS AR Section 7.3.1.1, the high voltage supply to the startup channels is adjustable with an upper limit to prevent inad.vertent detector ove r-volt age. This high voltage is automatically disconnected at a preset power level indicated on the v1.de range channels.

In Feb ruary,1979, the setpoints of JSH-1133-7 and NSH-1134-7 were changed from 10-3: to 10-2: to insure that the 1 10 cps5 scram protection would be available during refueling. Th 3 are the preset power levels on the wide range channels at which the higa toltage to the startup channels would be disconnected. Following completion of the refueling shutdown, this voltage cut-off setpoint was returned to its original setting of 10-3%.

During the period from October through December,1979, the plant was shut down for installation of region constraint devices (RCD's). Subs equent investigation has revealed that with the setpoints of USH-1133-7 and NSH-1134-7 at 10-3: power, the high voltage to the startup channels would be cut off before reaching the 105 cps setpoint. Durin$ region constraint device installation, tria reactor mde switeft was in the " refueling" po-siti on.

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REPOPJABLE OCCURRENCE 80-02 ISSUE O Page 2 of 3 EVENT DESCRIPTION: (Cont' d)

Per LCO 4.4.1 Table 4.4-1, the ;i 10 5cps scram setpoint was required to be operable at this time. Failure to mect the permissible bypass condition resulted in operation under a degraded mode of LCO 4.4.1.

During the period of region constraint device installation, no fuel handling took place; thus, no unplanned change in core reactivity would be expected.

Core reactivity was being monitored as required by LCO 4.5.2 during this period of reactor vessel internal maintenance.

CAUSE DES CRIPTION; Lack of startup channel scram protection during region constraint device in-stallation was a result of the icproper setpoints on the high voltage cut-off from the wide range channels to the startup channels. This setpoint was initially used to pravent detector over-voltage, thus lengthening detector life. The setpoint of 10-3% was determined in the initial plant design and had been in effect since that time.

CDRRECTIVE ACTION:

Upon determination that this problem existed, a setpoint change form was initiated to permanently place the setpoints of NSH-ll33-7 and NSH-1134-7 at 10-2%, thus ensuring operability of the ji 105 cps startup channel scram.

Appropriate surviellance procedures have also been revised to reflect this new setpoint.

No further corrective action is anticipated or required.

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P2 PORTABLE OCCURRENCE 80-02 ISSUE O Page 3 of 3 Prepared By: Ahe Cathy C. Eirsch Technical Services Technician Reviewed By: ' /f #

. W.'Gihm Technical Services Supervisor Reviewed By:

Frank !!. Mathie Operations Manager Approved By: / b Yezu d e Don Warembourg #

Manager, Nuclear Production

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