ML20009A542

Forwards LER 81-038/03L-0.Detailed Event Analysis Encl

ML20009A542
Person / Time
Site:	Fort Saint Vrain
Issue date:	06/05/1981
From:	Warembourg D PUBLIC SERVICE CO. OF COLORADO
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20009A543	List: ML20009A542 ML20009A550
References
P-81163, NUDOCS 8107130294
Download: ML20009A542 (4)

Text

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puhue senice company or conomde 16805 ROAD 19%

PLATTEVILLE, COLOR ADO 80651 June 5, 1981 Fort St. Vrain Unit No. 1 -- ~h/

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P-81163 ,

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Mr. Karl V. Seyfrit, Director " Wt Nuclear Regulatory Commission ,

Region IV ' ,/

Office of Inspection and Enforcement I$Ngh, g 611 Ryan Plaza Drive Suite 1000 Arlington, Texas 76012 Re ference : Facility Operating License No. DP R-34 Docket No. 50-267

Dear Mr. Seyfrit:

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

81-038, 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 j Reportable Occurrence Report No. 50-267/81-038.

l Very truly yours, Wul Mv Don Warembourg bbnager, Nuclear Production DW/cis Enclosure cc: Director, MIPC 96 l 8107130294 810605 PDR ADOCK 05000267 S PDR

r REPORT DATE: June 5, 1981 REPORTABLE OCCURRENCE 81-038 ISSUE O OCCURRENCE DATE: May 7, 1981 Page 1 of 3 FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO 16805 WELC COUNTY ROAD 19 1/2 PLATTEVILLE, COLORADO 80651 REPORT N0. 50-267/81-038/03-L-0 f

! Final IDENTIFICATION OF OCCURRENCE:

During May, two Class I hydraulic shock suppressors were taken out of service, one at a time, for modification. This is reportable per Fort St. Vrain Technical Specification AC 7.5.2(b)2 as a degraded mode of LCO 4.3.10.

EVENT DESCRIPTION:

l In two separate occasions, while the plant was operating, operable

Class I shock suppressors were removed from service for modification.

I VSS-123 - Out of service from 1057 hours0.0122 days <br />0.294 hours <br />0.00175 weeks <br />4.021885e-4 months <br /> on May 7, 1981, until 0915 hou's on May 9, 1981.

i VSS-113 - Out of service from 0800 hours0.00926 days <br />0.222 hours <br />0.00132 weeks <br />3.044e-4 months <br /> until 1320 hours0.0153 days <br />0.367 hours <br />0.00218 weeks <br />5.0226e-4 months <br /> on May 11, 1981.

Technical Specification LCO 4.3.10 states that all shock suppressors

! on Class I piping systems shall be operu51e if the reactor is not i shutdown or refueling. The LCO further states that continued power i operation after a shock suppressor is cetermined to be inoperable is

permissible only during the succeeding 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> unless the shock l

suppressor is made operable sooner or replaced.

l l The two vent stack shock suppressors removed for modification were returned to service within the 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

CAUSE

, JESCRIPTION:

t In April, 1979, during performance of the hydraulic snubber functional test which required each refueling by the Fort St. Vrain Technical Specifications, it was found that the 16 vent stack snubbers did not have bleed capability. This was reported on July 3, 1981, as part of Reoortable Occurrence 79-13.

The 16 non-bleeding hydraulic snubbers were modified or replaced so that bleed capability was available.

.S REPORTABLE OCCURRENCE 81-038 ISSUE 0 Page 2 of 3 During the evaluation of seismic restraints in accordance with I & E Bulletin 79-14, it was determined that the bleed rate on these 16 snubbers should be zero.

The bleed rate of the 16 vent stack snubbers was adjusted to zero with the snuobers in place. In order to verify that the bleed rate is in fact zero, each snubber is being removed, tested, and replaced.

During November,1980, five snubbers were removed from service for test, resulting in five events of operation in a degraded mode allowed by LCO 4.3.10. This was reported on January 27, 1981, in Reportable Occurrrence 80-65.

On May 8, 1981, it was decided to modify the shock suppressors to their original configuration with zero bleed rate block valves.

A Change Notice was prepared, and VSS-123 was removed and modified.

VSS-113 was removed, but not modified. It was returned to normal operation later the same day. The remaining affected snubbers will be modified when possible. These snubbers presently have zero bleed rate.

CORRECTIVE ACTICN:

VSS-123 was modified and returned to service.

VSS-ll3 was returned to service.

With respect to VSS-113 and VSS-123, no further corrective action is anticipated or required.

REPORTABLE OCCURRENCE S1-038 ISSUE 0 Page 3 of 3 1

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Prepared By: .

Asa B. Reed Technical Services Technician

Reviewed By

Services Supervisor Reviewed By:

f Frank M. Mathie l Operations Manager Approved By: d Yu e Don warembourg &

Manager, Nuclear Production l

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