ML20028G196

RO 3-83-2/IP:on 830126,containment Isolation Valve MO-5244, Associated W/Hpci Turbine Exhaust Line Vacuum Breaker,Failed to Fully Close During Local Leak Rate Testing.Caused by Solidified Lubricant in Valve Operator

ML20028G196
Person / Time
Site:	Peach Bottom
Issue date:	01/28/1983
From:	Ullrich W PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
RO-3-83-2-IP, NUDOCS 8302070509
Download: ML20028G196 (3)

Text

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Cortified By [ /

PHILADELPHIA ELECTRIC COMPANY PE AcH eoTYOM atom 8c POWER sTATioM n n.3. sox aos l out.YA. PENNsVLVaMla 17314 l

1 January 28, 1983 Mr. R. C. Haynem l j Administrator U.S. Nuclear Regulatory comission Region I '

,, 631 Park Avenue

j King of Prussia, PA 19406 j .t i SUILTECf3 REPORTABLE CCCURRENCE - PROMPT NOTIFICATION

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j confirming J. F. Mitman's telephone conversation with A. R. Blough, I

Region I, United States Nuclear Ragulatory Commission on 1/26/83.

1 meterance: Docket tio. 50-278 Peach Botton Unit 3

! Technical specifi,qation 3.5.C and 3.7.D.2

• i Report No. 3-83-2/IP occurrence Date: 1/2G/83 i

Identification of Occurronce s j

At approximately 9:30 p.r.t. on 1/26/83, during 1ccal leak rate testing l of a containment isolation valve (MO-5244) associated with the SPCI

' turbine exhaustr line vacutas breaker, the valve failed to fully close.

, A unnual va,1ve in the same line was closed, the HPCI System was, l' declared inoperable, and surveillance testing of appropriate ECCS I

equipeant was initiated as required by the Technical-Specificatione.

When the RCIC system was tested, the turbine throttle valve reset l motor tripped Curing the portion of the surveillance test that checks l

t remote throttle valve reset capability. A shutdown was initiated in

, response to Technical specification requirements. Following re-

,; placement of the throttle valve motor hm=1a, valve and DCIC

's operability was re-established, the shutdown was terminated, and j reactor power was recovered to nawi== capaht11ty.

Because the resident NRC Inspector had been promptly notified of the HPCI vacutan breaker isolation valve problem, the latar problem with the BCIC throttle valve was inadvertently not reported to the resident j inspector nor was the NRC Operations Center notified.

t' Conditione Prior to occurrences I

• j Unit 3 operating at its mav4="- capability during EOL coast-down f .

(approximately 540 D5de) . ,

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I Apparent Cause of Occurrence s

Routine leak rate testing of the HPCI vacuu

n breaker isolation valvo

'j 30-5244 indicated that the valve limitorque operator prevented the valve from closing fully. Following valve operator dismantling, the cause of the improper cperation was determined to be solidified lubricant in the valve operator.

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During the surveillance test of the EtCIC System, the throttle valve is tripped and reset.

During the relatehing of the valye, the thermal overloads on the valve motor tripped. These thermal over-Loads were replaced and the valve was stroked satisfactorily. Later I

• on 1/27/83, the valve stem was Iubricated and p*oper operation of the latching mechanism and valve sotor again verified.

Analysis of Occurrence:

9 1 When the HPCI vacuum breaker isolation valve was identified as being unable to close, an in-lir.e manual isolation valve was closed to maintain containment integrity. The second isolation valve in this I penetration is the HPCI exhaust line check valve which was operable

! during this period. With the vacuum b.:aaker line isolated, the HPCI System is, in fact, operable. However, if it is cycled on and off,

' there is a potential for water to enter the turbine exhaust line creating starte.

a significant back pressure on the turbine on the successive In any case, the inttial operation of the HPCI turbine wculd not be affected.

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} The open.lector operated vacuum breaker isolation valve MD-5244 is normally l

It is automatically closed if prhary coolant pressure is below 103 psig and drywell pressure is above 2 psig. This operation isolates the torus air space from the HPCI turbine exhaust line during periods when HPCI operation is not required. It will also j

i permit torus water to seal the HPCI exhaust line check valve after HPCI operation is ng longer required. . .

Failure of this vacuum breaker isolation valve to fully close has 2

minimal safety significance because the in-line check valve was operable and in a closed condition. Continued operation of the unit w with the manual valve closed in the vacuum breaker line is canser-vative because HPCI was maintained S1 an operabIs condition at least i for the first start, but van declare,i inoperable based on Technical l

i specification requirecancs.  !

I i As indicated above, ECIC was casted due to declaring the NPCI inoperable.

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' '. ) position. The throttle valve on RCIC is normally in an open and operating properly.BCIC Therefore, was capable of starting automatically

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! However, if the BCIC had tripped during this operation, it could not have been re-started frons the control room.

! The probims was identified during the valve stroking pertion I

of the surveillance test. The valve was declared inoperable for

{ app ==i--taly 30 minutes. During this time, the th-1 overimAm

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were replaced and the valve was satisfactorily stroked to verify operability.  ;

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. . _ . . . . - - u_. _ . . . _ . . . _ I 3-t Correceive' Actions 1 As indicated above, i m diate corrective action was taken when the a vacutna breaker m::stor operated isolation valve failed to close by

) closing an in-line manual valve and dec Laring the HPCI irmperable. *

, Surveillance time. testing for other ECCS systems was initiated at that On 1/27/83 the HPCI motor operat or was repaired. Hardened lubricant was raroved and new lubricant applied.

and torqiie switches were checked and realigned. The limit evitches j i leak rate tent van performed inte on 1/27/S3. A muccessfiti local

, As indicated above, the ItCIC throttle valve was returned to an i <

• operable status within 30 minutes of the failure by replacing the thermal ovarloads.

Further preventive maintenance was performed on i

1 1/27/83 by lubrication of the valve stem and additional stroAing.

l To enhance licensed operators' knowledge of reporting requirements ,a

, portion of the licensed operatcr requalification program will be I i dedicated'to cWh. this subject during the second requalification lectura Previous cccurrenee-None. '

l . Very truly yours, I / -

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i W. T. Ullrich Station Superin*=ad'-at 4

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