ML20027D951
| ML20027D951 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 10/29/1982 |
| From: | Woolever E DUQUESNE LIGHT CO. |
| To: | Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| 10CFR-050.55E, 10CFR-50-55E, 10CFR-50.55E, 2NRC-2-040, 2NRC-2-40, NUDOCS 8211100437 | |
| Download: ML20027D951 (5) | |
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2NRC-2-040 (412) 787 - 5141 m
(412)923 - 1960 Telecopy (412) 787-2629 Nuclear construction Division Robinson Plaza, Building 2, Suite 21o October 29, 1982 Pittsburgh, PA 15205 United States Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, PA 19406 ATTENTION:
Mr. R. Haynes Administrator
SUBJECT:
Beaver Valley Power Station - Unit No. 2 Docket No. 50-412 Westinghouse Motor-operated Gate Valves - Closure Problems Significant De ficiency Report No. 80-06 Gentlemen:
Pursuant to the requirements of 10CFR50.55(e), the " Final Report en Westinghouse Motor-operated Gate Valves" is attached for your review. If there are any questions concerning this report, please contact the Beaver Valley Unit 2 Project Office.
DUQUESNE LIGHT COMPANY BY E. Jp WoMeyer Vice President JMM/wjs Attachment cc:
Mr. R. DeYoung, Director, Office of Inspection and Enforcement (w/a) (3)
NRC Document Control Desk (w/a)
Mr. G. Walton, NRC Resident Inspector (w/a)
Ms. E. Doolittle, Project Manager (w/a)
,SUJSCl}pt AND SWORN TO JEFORE ME THIS ff/tDAY OF ((!"b+h4 /
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United States Nuclear R2gulatory Commission page 2 COMMONWEALTH OF PENNSYLVANIA )
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COUNTY OF ALLEGHENY
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, a Notary Public in and for said Common-wgaEh d County, personally appeared E. J. Woolever, who being duly sworn, e, posed, and said that (1) he is 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 best of his knowledge, information and belief.
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, United States Nuclear Regulatory Commission l
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4 JMM/wjs Attachment bec:
C. R. Bishop (w/o attachment)
T. D. Jones J. M. Markovich H. M. Siegel R. J. Swiderski D. H. Williams C. E. Ewing (w/ attachment)
M. H. Judkis (4)
NCD File J. Pedro (NUS)
P. RaySircar (3)
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J. Sutton (S&W) i i
REFERENCES:
- 1. Significant Deficiency Report 80-06
- 2. IE Bulletin No. 81-02, Supplement 1, " Failure of Gate Type Valves to Close Against Differential Pressure"
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BEAVER VALLEY POWER STATION - UNIT NO. 2 DUQUESNE LIGHT COMPANY i
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Final Report on Significant Deficiency 80-06 Westinghouse Motor-operated Gate Valves 9
1.
SUMHARY IE Bulletin No. 81-02, Supplement No. 1, stated that closure problems could be. anticipated with the entire line of Westinghouse Electro-Mechanical Division (W-EMD) manufactured motor-operated gate valves. Several of these valves are scheduled for installation at Beaver Valley Unit No. 2 (BVPS-2).
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2.
IMMEDIATE ACTION TAKEN l
For those valves which were incapable of meeting functional requirements, Westinghouse began to evaluate several corrective measures which would j
ensure valve operability under specified system conditions, taking into account closing or opening functions and operating differential and line pressures as they apply to BVPS-2.
I 3.
DESCRIPTION OF THE DEFICIENCY The gate valve closing problem first surfaced when several valves failed I
to fully close against high flow and high differential pressure conditions during plant start-up testing at the Almaraz Nuclear Station in Spain and during the Electric Power Research Institute Power Operated Relief Valve l
(PORV) block valve tests at Duke Power's Marshall Station. Typically, these valves operated through 75 percent of their full disc travel leaving
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about 5 percent of the flow passage unsealed. Subsequent strain gage j
testing showed the stem thrust loads required to fully close the valve to be 50 percent larger than original design calculations predicted.
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4.
ANALYSIS OF SAFETY IMPLICATIONS i
f Some of the potential safety consequences of. the valves' failure to fully j
close against differential pressure are as follows:
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Potential Consequences j
l 1.
(PORV Block Valves) Potential incomplete isolation of pressurizer l
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2.
Potential cavitation of a centrifugal charging pump or safety injec-tion pump due to operation beyond maximum runout flow.
3.
Potential inability to perform post-accident containment isolation.
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Potential degradation of safety injection flow below values given in the safety analysis report.
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Potential inability to isolate Reactor Coolant System pressure boundary.
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5.
CORRECTIVE ACTION TO REMEDY THE DEFICIENCY I
Since Duquesne Light Company issued Interim Report No. 4 to the NRC, the
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d required modifications of 37 Westinghouse EMD gate valvesiat the BVPS-2 site have been completed. The valve modifications involved either a torque switch adjustment or a torque. control to limit control closure adjustment accompanied by a gear ratio change on the valve operator. This is required in order to ensure valve operability under specified system conditions -
taking into account closing or opening functions and operating differential
.nd line pressures.
The BVPS-2 project office 'has received Westinghouse reports which provide a summary of the valve modifications. These reports will be made available to the Resident Inspector upon request.
6.
FINAL REPORT This is the final report. No further corrective action is required.