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)

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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

i,,j l proper trip points. Trip settings being checked on a =cnthly basis. Redis12n of I i,;,; ] system being evaluated. l li t a l ! I

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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

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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

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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

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CAUSE  :

! DESCRIPT30I:

Dirt buildup and accumulation in the electrical switches prevented them 4

from making proper contact.

i i CORRECTIVE

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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

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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: -

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. 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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