05000298/LER-1980-036, Forwards LER 80-036/03L-0

Forwards LER 80-036/03L-0

ML20002A766
Person / Time
Site:	Cooper
Issue date:	10/31/1980
From:	Lessor L NEBRASKA PUBLIC POWER DISTRICT
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20002A767	List: 05000298/LER-1980-036, Forwards LER 80-036/03L-0 05000298/LER-1980-036-03, /03L-0:on 801003,valve RW-AO-95 Would Not Close within Time Limit.Caused by Miller-64A One Piston Air Operator,Which Is Valve Operator on Discharge Valve,Not Closing.Valve Tested Satisfactorily for Last Four Wks
References
CNSS800640, NUDOCS 8011210495
Download: ML20002A766 (2)

LER-1980-036, Forwards LER 80-036/03L-0

Event date:
Report date:
2981980036R00 - NRC Website

text

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COOPER NUCLEAR STATtoN

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Nebraska Public Power District

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CNSS800640 October 31, 1980-

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@g Mr. K. V. Seyfrit, Director U.S. Nuclear Regulatory Commission y

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Region IV 611-Ryan Plaza Drive N

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'O Arlington, Texas 76011

Dear Sir:

1 This report is submitted in accordance with Section 6.7.2.B.2 of the Tect nical Specifications for Cooper Nuclear Station and discusses a reportable occurrence that was discovered on October 3, 1980.

A li-censee event report form is also enclosed.

Report No.:

50-298-80-36 Report Date:

October 31, 1980 Occurrence Date: October 3, 1980 i

Facility:

Cooper Nuclear Station Brownville, Nebraska 68321 l

Identification of Occurrence:

A condition resulting in operation in a degraded mode as permitted by the limiting condition for operation _ established in Section 3.7.D.2 of the Technical Specifications.

l Conditions Prior to Occurrence:

l The reactor was operating at a steady state power level of approx-imately 95% of rated thermal power.

Description of Occurrence:

l During performance of-surveillance procedure 6.3.1.4, a discharge l

valve from the drywell equipment Sump "G" (RW-AO-95), would not close in <15 seconds as specified in Table 3.7.1 of the Technical Specifications.

- Designation of Apparent Cause of Occurrence:

The apparent cause of this occurrence is believed to be associated with a non-repetitive friction factor between the piston U-cup seal and cylinder of the air operator, h s id 801 1210 '/f5 -

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' Mr. K. V.'Seyfrit

- October 31. 1980-Page 2.

Analysis of Occurrence:

RW-AO-95 is.the outboard-isolation-valve on the discharge line from drywell equipment drain Sump "G".

RW-AO-94 is the inboard isola-tion valve and was: tagged closed following this occurrence.

KR-AO-95 is operated by a piston cylinder type air operator with a solen-oid pilot valve which controls the air flow to the air operator.

RW-AO-95 can also be manually operated with a handwheel.

At the time of this occurrence, the subject air operator was slug-gish in' operation. -Subsequent to several cycles of the air oper-ator, the sluggish operation was resolved and the closing time requirement was attained.

Piston cylinder type air operators-have been previously observed to become sluggish in operation after the operator has remained in one l

position for a period of time.- It is believed that this observa-tion is an inherent problem with piston cylinder type air operators and can be resolved by increasing the cycling frequency and/or installing an in-line lubricator on the air supply line._ The recommended resolution in this case is to increase the cycle frequency from quarterly to monthly.

This occurrence had no-adverse affect on the public health and safety.

Corrective Action

The solenoid pilot valve associated with the subject air operator was inspected and tested satisfactorily. The subject air operator has been operated on a weekly basis with no apparent sluggish operation._ Based'on the above testing, RW-AO-94 and 95 along with RW-AO-82 and 83, which'are the corresponding valves associated with

- the drywell floor drain Sump "F"

have been included in the monthly

. valve operability section of Surveillance Procedure 6.3.1.4.

Sincerely, 4

L. C. Lessor Station Superintendent Cooper Nuclear Station LCL:cg Attach.

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