05000267/LER-1981-047, Forwards LER 81-047/03L-0.Detailed Event Analysis Encl

Forwards LER 81-047/03L-0.Detailed Event Analysis Encl

ML20010H754
Person / Time
Site:	Fort Saint Vrain
Issue date:	09/04/1981
From:	Warembourg D PUBLIC SERVICE CO. OF COLORADO
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20010H755	List: 05000267/LER-1981-047, Forwards LER 81-047/03L-0.Detailed Event Analysis Encl
References
P-81219, NUDOCS 8109290262
Download: ML20010H754 (5)

LER-1981-047, Forwards LER 81-047/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
2671981047R00 - NRC Website

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public Service Company *F CcEcmede j

September 4, 1981 Fort St. Vrain Unit No. 1 P-81219 i

Mr. Karl V. Seyfrit, Director Nuclear Regulatory Commission Region IV Office of Inspection and Enforcement 611 Ryan Plaza Drive Suite 1000 Arlington, Texa: 76012

Reference:

Facility Operating License No. DPR-34

. Docket No. 50-267

Dear Mr. Seyfrit:

Enclosed please finc a copy of Reportable Occurrence Report No. 50-267/81-047, Preliminary, submitted per the requirements of Technical Specification AC 7.5.2(b)1 and AC 7.5.2(b)2.

Also, please find enclosed one copy of the Licensee Event Report for Reoortable Occurrence Report No. 50-267/31-047.

Very truly yours, l

Mt%/

l Don Warembourg Manager, Nucip

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REPORT DATE:

Seotembe' 4, 1981 REPORTABLE OCCURRENCE S1-047 ISSUE 0 OCCURRENCE DATE:

Aucust 7, 1981 Page 1 of 4 FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO 16805 WELO COUNTY ROAD 19 1/2 PLATTEVILLE, COLORADO 80651 REPORT NO. 50-267/81-047/03-L-0 Preliminary IDENTIFICATION OF OCCURRENCE:

During the August performance of the mor.thly check of the helium circu'itor seal malfunction pressure differential

switches, it was discovered that one of the twelve switch units tripped outside the limits specified in LCO 4.4.1, Taole 4.4-3.

This is reportable per Fort St.

Vrain Technical Specifications AC 7.5.2(b)1 and AC 7.5.2(b)2.

EVENT

DESCRIPTION

On August 7, 1981, while operating at 69f. thermal power and 220 MWe electrical, instra. tent personnel performed the circulator seal malfunction (buffer-mid-buffer) switch operability check.

The switches are normally calibrated on an annyal basis; however, due to-the problems cited in the previous reports as listed on the LER, a check of buffer-mid-buffer trip settings on a monthly basis has been undertaken as an interim measure to test operability.

There are twelve buf fer-mid-cuf fer switch units, three per circulator.

Each switch unit contains two electrical switches.

The range of the sensing element is from (-) 100 inches of water to zero to (+) 100 inches of water. One of the electrical switches in each unit must ocerate at greater than or equal to (-) 10 inches water (negative buffer-mid-buffer), and the other electrical switch must operate at less than or eaual to (+) 80 inches of water (positive tuffer-mid-buffer; ;er Table 4.4-3.

The trip settings for the twelve switches are listed in Table 1.

- The switch setting, which was found to be less conservative than

. hose established by the Technical Soecification, did not prevent the fulfillment of the functional requirements of the system.

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REPORTABLE OCCURRENCE 81-047 ISSUE O Page 2 of 4

CAUSE

DESCRIPTION.

Oirt buildup and accumulation in the electrical switches prevented them from making proper contact.

CORRECTIVE ACTION:

The trip setting of the electrical switch was re-adjusted to the proper trip point and the test satisfactorily completed.

Due to the continuing problems being experienced with the electrical switches, the interim check of the trip settings is ceing cenducted on ; monthly basis.

The investigation of the probleu associated with the helium-i circulator seal malfunction trip switches has been completed, and Public Service Company Nuclear Engineering Department is proceeding on a path to replace the existing equipment.

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I REPORTABLE OCCURRENCE 81-047 ISSUE O Page 3 of 4 TABLE 1 As Found Inches H 0 As Left Inches $ 0 7

Increasing Decreasing Increasing Decreasing Trio Point Trio Point Trio Point Trio Poir,t l

1A Circulatori PDIS-21149

+76

- 5

+76

- 5 PDIS-21151

+76

- 7

+76

- 7 PCIS-21153

+77

- 8

+77

- 8 IB Circulator PDIS-21155

+74

- 4

+74

- 4 PDIS-21157

+72

- 15(D

+72

- 9 PDIS-21159

+77

- 4

+77

- 4 1C Circulator PDIS-21150

+75

- 8

+75

- 8 POIS-21152

+73

- 9

+73

- 9 I

P0I5-21154

+75

- 4

+75

- 4 1D Circulator PDIS-21156

+74

- 3

+74

- 3 PDIS-21158

+73

- 8

+73

- 8 PDIS-21r!J

+74

- 6

+74

- 6

@ Denotes switch which was out of tolerance.

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REPORTABLE OCCURRENCE 81-047 ISSUE O Page 4 of 4 4

Prepared By:

Asa B. Reed Technical Services Techni ian Reviewed By: WM771c43 M1Tt McBrice Technical Servica Manager n

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Reviewed By:

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Edwin 07 Hf1 r '

Station Manager Approved By:

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Don Warembourg

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Manager, Nuclear Production I

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