ML20108C801
| ML20108C801 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 10/29/1984 |
| From: | Woolever E DUQUESNE LIGHT CO. |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| 2NRC-4-178, 83-01, 83-1, NUDOCS 8411190079 | |
| Download: ML20108C801 (4) | |
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412 787 51 1 Nuclear Construction Division y,s copy Robinson Plaza, Building 2, Suite 210 Pittsburgh, PA 15205 October 29, 1984 United States Nuclear Regulatory Commission Region 1 631 Park Avenue King of Prussia, PA 19406 ATTENTION:
Dr. Thomas E. Murley Administrator
SUBJECT:
Beaver Valley Power Station - Unit No. 2 Docke t No. 50-412 Suplement 1 to Potential Deficiency of Westinghouse Gate Valve Position Indication Significant Deficiency Report No. 83-01 Final Report Gentlemen:
Pursuant to the requirements of 10CFR50.55(e), Supplement 1 to the Final Report on the Potential Deficiency in Westinghouse Gate Valve Pos it ion Indication is attached for your review.
If there are any ques tions conce rning this report, please contact the Beaver Valley Unit 2 Project Office.
DUQUESNE LIGHT COMPANY By
'(
vov' E. Q'. Woolever Vice President SDH/wjs Attachment cc:
Mr. R. DeYoung, Director (3) (w/a)
Mr. B. K. Singh, Project Manager (w/a)
Mr. G. Walton, NRC Resident Inspector (w/a)
NRC Decument Control Desk (w/a)
SUBSCRIBED AND SWO,RN TO BEFORE ME THIS 39g/DAYOF dicI,dt,t
, 1984.
Suk E0 a 3 R A Notary Public ANITA ELAINE REITER, NOTARY PUBLIC 8411190079 841029 ROBINSON TOWNSHIP, ALLEGHENY COUNTY PDR ADOCK 05000412 S
POR MY COMMISSION EXPIRES OCTOBER 20,1986
7 U ited Stctoc Nuciccr RIgulctory Connicsion '
'Dr. Thom m E. Murlcy.
Page 2 COMMONWEALTH OF PENNSYLVANIA- )
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SS:
COUNTY OF ALLEGHENY
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On this c2 M day of
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, before me, a Notary Public in and for said Commonwealth and County, personally appeared E.- J. Woolever, who being duly. sworn, deposed and said that (1) he i~s Vice.
President of Duquesne Light,-(2) he-is duly authorized to execute and file the foregoing' Submittal on. behalf of said Company, and (3) the statements set forth in the Submittal are true-and correct' to the ' bes t of his knowledge.
L Notary Public.
ANITA ELAINE REITER, NOTARY PUBLIC ROBINSON TOWNSHIP, ALLEGHENY COUNTY MY COMMISSION EXPIRES OCTOBER 20,1986 '
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_ ~ BEAVER VALLEY POWER STATION - UNIT NO. ' 2 '
- DUQUESNE LIGHT. COMPANY.
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-Supplement-1 to Final Report on cPotential Deficiency of Westinghouse
' Gate Valve Position Indication
.1.
SUMMARY
s Westinghouse identified a'. potential (significant ;d' ficiency in ' Westing--
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- house supplied EMD _ gate.valvec position indication' instrumentation which.
could. result :in an. indication that the valve' is. " closed" prior to. the -
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valve rdise; fully isolating flow.' Should the. valve, stall.or bind follow-ing the i premature indication,. the operatior would. have : an inaccurate indication of true. valve position.
2.
IMMEDIATE ACTION'TAKEN On January 12, 1983, - Duquesne' Light ' Company -(DLC) notified B. Crocker of.the Region.I office by telephone.
DLC also. instructed Westinghosue to continue with their investigation of the. potential deficiency.
DLC submitted subsequent reports in accordance - with the requirements: of 10CFRSO.55(e)-on'Feburary 11, 1983; April 29,.1983; and May 23, 1983..
3.
DESCRIPTION OF DEFICIENCY A geared limit switch rotor ' is set to provide an electrical bypass. 'of -
the OPEN - torque. switch at the beginning of the opening..' stroke.
On a closing ~ stroke, this. switch' changes state before, the - flow -. path is completely blocked.
As a result, it - is likely. that monitor and/or indicator lights also operated by that rotor will indicate valve closure slightly before the flow path is completely shut of f.
If the valve were to stop between this setpoint and the ' full shutoff. position, a flow path through the valve could exist even though a CLOSE indica-tion had been achieved.
The various generic gate valve applications have been reviewed to determine those that may result in un acceptable consequences. -These are:
a) Hot leg safety injection (high and low pressure) b) Alternate cold leg (high pressure) injection- (3-loop plants only) c) cold leg injection (low head) i l~
All valves which have been identified as potentially requiring modifi-
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cation and which incorrect position indication by itself could cause an'
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unacceptable situation that violates the established licensing basis (L
f o r Beaver Valley Power Station Unit-2 are:
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8616 8814 8886 8888A 8889 88888 l.
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4.
ANALYSIS OF SAFETY IMPLICATIONS
-Inaccurat'e position indication of safety-related iisolation valves could result 1 in ; improper ~ system or-system operation : and possible inaccurate operator. response, degrading the af fected system's. ability to perform
-.its safety -function.-
- 5. ' CORRECTIVE ACTION TO REMEDY DEFICIENCY Westinghouse completed a plant specific review for Beaver. Valley' Power.
Station Unit 2.
It confirmed that the six (6) valves listed above were the only' safety related valves which would require corrections due to this. potential significant deficiency.
DLC will modify the Westing.
house'-supplied position' indication wiring :on each of.the six ' safety related valves to use a torque switch input in place ~ of ~ the. current limit switch. This change will ensure' that_ true. valve position' will be=
provided to the' operator for these ~ six EMD gate valves. The elementary drawings for these changes to. these' six valves have -been issued.
The
-revised schedule for - the expected - completion - of th'e iework on these valves-is December 14, 1984.'
6.
ADDITIONAL REPORTS It is expected that this will be ~ the final report to be submitted ' on this potential significant deficiency.
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