ML19305E836

LER 80-020/03L-0:on 800418,during Testing,Two of 12 Helium Circulator Seal Malfunction Pressure Differential Switch Units Were Discovered Tripped Outside Tech Spec Limits. Caused by Dirt Accumulation in Electrical Switches

ML19305E836
Person / Time
Site:	Fort Saint Vrain
Issue date:	05/15/1980
From:	Gahm J PUBLIC SERVICE CO. OF COLORADO
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19305E834	List: ML19305E833 ML19305E836
References
LER-80-020-03L, LER-80-20-3L, NUDOCS 8005200507
Download: ML19305E836 (5)

Text

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NOC (b;'M 365 U. S. NUCLE AR REGULATORY CCMMISSION (7 77)

LICENSEE EVENT REPORT 8005200507 C) CcNTRcL stCCx: I  ! I I I I g (PLEASE PRINT OR TYPE ALL REQUIREO INFORMATION) lo t i8 l 7l c I O 7

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@l 69 014 Il 18 l 810 l@l O! 5l EVENT DATE 74 75 11QATE AEPCAT 31 Sl Ol@ dG EVENT DESCRIPTION AND PROBA8LE CCNSEQUENCES h lo12l lDuring testing, it was discovered that two of twelve helium circulater seal malfunc- l lo!3l l tion pressure differential switch units tripped outside the limits of LCO 4.4.1, I laiAIITable 4.4-3. Reactor coeration durinz test interval. Recortable oer Technical Soeci-l l a i 3 ! t fication AC 7.5.2(b)1 and AC 7.3.2(b)2. No effect on public health or safety. Re- l la is l ldundant system available and operable. Similar reports are RO 77-47 Final. and Pre- l l c j 71 l liminary reports RO 78-2 7. RO 79-32. RO 79-56. R0 80-07, and R0 S0-16. I I

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JJ J4 36 40 ei 47 CAUSE CESCRIPTICN AND CCRRECTIVE ACTICNS h lilal lITT Barton Model 239 pressure dif ferential switches failed to actuate at trio coint I til-l jdue to dirt accu =ulation in electrical switches. Affected switches re-adiusted to i

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t i REPORT DATE: May 15, 1980 REPORTABLE OCCURRENCE 80-20 l' ISSUE O OCCURRENCE DATE: Aoril 18,1980 Page 1 of 4

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FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO 16805 VELD COUNTY ROAD 19 1/2 PLATTEVILLE, COLORADO 80651 REPORT NO. 50-26 7/80-20/03-L-0 i

Final IDENTIFICATION OF OCCURRENCE :

During performance of the monthly check of the helium circulator seal malfunction pressure dif ferential switches, it was discovered that two

! of twelve switch units tripped outside the limits specified in LCO 4.4.1, Table 4.4-3.

, Since reactor operation had taken place during the test interval, this i is reportable per Fort St. Vrain Technical Specification AC 7.5.2(b)1 and AC 7.5.2(b)2.

EVENT DESCRIPTION:

During normal plant operation, instrument personnel performed the circu-lator seal malfunction (buffer-mid-buffer) switch operability check. The switches are normally calibrated on an annual basis; however, due to the problems cited in the previous reports as listed on the LER, a check of buf fer-mid-buffer trip settings on a monthly basis has been undertaken as an interim measure to test operability.

There are twelve buffer-mid-buffer switch units, three per circulator.

Each switch unit contains two electrical switches. The range of the i swnsing element is f rom (-) 100 inches of water to zero to (+) 100 inches of water. One of the electrical switches in each unit must operate at 4

greater than or equal to (-) 10 inches water (negative buffer-mid-buf fer),

and the other . electrical switch must operate at less than or equal to (A) 80 inches water (positive buffer-sid-buffer) per Table 4.4-3.

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

The switch settings which were found to be less conservative than those established by the Technical Specification did not prevent the fulfillment of the functional requirements of the system.

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REPORTABLE OCCURRENCE 80-20

-ISSUE 0 Page 2 of 4 CAUSE  :

! DESCRIPT30I:

Dirt buildup and accumulation in the electrical switches prevented them 4

from making proper contact.

i i CORRECTIVE ACTION:

The trip settings of the electrical switches were re-adjusted to the proper trip points.

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

The investigation of the problem associated with the helium circulator seal malfunction trip switches has been completed, and Public Service

Company Nuclear Project Department is proceeding on a path to replace the

existing equipment.

No further corrective action is anticipated or required.

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REPORTABLE OCCL~ARENCE 80-20 ISSUE O Page 3 of 4 TABLE 1 As Found Inches H2O As Left Inches H2O Increasing l Decreasing Increasing Decreasing Trip Point i Trip Point Trip Point lt Trio Point lA Circulator PDIS-21149 '77 -5 +77 -5 PDIS-21151 +74 -7 +74 -7 P DIS-2115 3 +75 -5 +75 -5 13 Circulator PDIS-21155 +77 -5 +77 -5 PDIS-2115 7 +90h - 7 ,, +73 -7 PDIS-21159 +73 -9 +73 -9 1C Circulator PDIS-21150 +76 -7 +76 -7 PDIS-21152 +82h -21 h +74 -7 PDIS-21154 +76 -5 +76 -5 1D Circulator PDIS-21156 +74 -8 +74 -8 PDIS-21158 +77 -5 +77 -5 PDIS-21160 +75 -5 +75 -5 h Denotes switches which were out of tolerance.

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FIPORTABLE OCCURRENCE 80-20 ISSUE O Page 4 of 4

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Prepared By: _ 5 ' C. C

! Asa 3. Reed

.! Technical ';ervices Technician i

Reviewed By: -

//

. W. Tahm

! / Technical Services Supervisor i

Reviewed By:

Frank R. Mathie Operations Manager Approved By: 4~ [undw Don Warembourg gf Manager, Nuclear Prodhetion I

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