ML20023D377
| ML20023D377 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 05/10/1983 |
| From: | Woolever E DUQUESNE LIGHT CO. |
| To: | Allan J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| REF-PT21-83 10CFR-050.55E, 10CFR-50.55E, 82-06, 82-6, IEB-81-02, IEB-81-2, NUDOCS 8305200429 | |
| Download: ML20023D377 (5) | |
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y 2NRC-3-026 (412) 787 - 5141 (412)923 -1960 Telecopy (412) 787-26:9 May 10,1983 Nuclear Construction Division Robinson Plaza. Building 2 Sutto 210 Pittsburgh, PA 15205 United States Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, PA 19406 ATTENTION:
Mr. James Allen Acting Region Administrator
SUBJECT:
Beaver Valley Power Station - Unit No. 2 Docket No. 50-412 Limitorque Motor Key Failures Significant Deficiency Report No. 82-06 Gentlemen:
Pursuant to the requirements of 10CFR50.55(e), the " Final Report on Sheared Pinion Keys in Limitorque Motor Operators" is attached for your review.
If there are any questions coacerning this report, please contact the Beaver Valley Unit No. 2 Project Office.
DUQUESNE LIGHT COMPANY I
By Qil. J. Woolever Vice President JMM/wjs Attachment cc:
Mr. R. DeYoung, Director, Office of Inspection & Enforcement (w/a) (3) 1 Mr. _G. Walton, NRC Resident Inspector (w/a)
Ms. L. Lazo, Project Manager (w/a)
NRC Document Control Desk (w/a)
INPO Records Center (w/a)
SUBSCRIBED AND ORN TO BEFORE ME THIS g DAY OF
,6f 1983.
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Notary Public EWA G. LE2CNC/JC, NOTARY PUBLIC ilCc2iN2CN T07,N3HfP, ALLECHENY COUNTY IJY COMM;53!ON EXPIRES CCTC3ER 20,1956 l8M88!PJ88!g PDR
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United States Nuclect Regulatory Connaission Page 2 COMMONWEALTH OF PENNSYLVANIA )
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COUNTY OF ALLEGilENY
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On this
/d day of h
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before me, a Notary Public in and for said Commonwdith and County, personally appeared E.
J.
Woolever, who being duly sworn, deposed and said that (1) he is Vice Presi-dent of Duquesne Light, (2) he is duly authorized to execute and file the fore-going 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.
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No'tary Public ELVA G. LESONDAK, NOTARY PUBLIC ROSINSON TO?!NSHIP, ALLEGHENY COUNTY MY CCMMISSiON EXFIRES OCTOBER 20,1985
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s United Stctas Nuclear Reguistory Commission Page 3
(
bec: R. Coupland (w/ attachment)
C. E. Ewing J. C. Hoebel (4) l J. M. Markovich J. Pedro (NUS) s P. RaySircar (3)
J. Sutton (S&W)
J. F. Zagorski NCD File C. R. Bishop (w/o attachments)
T. D. Jones H. M. Siegel R. J. Swiderski D. H. Williams
REFERENCES:
(1) Significant Deficiency Report No. 82-06 (2) DMW-D-3022, dated August 9,1982, " Substantial Safety Hazard:
Limitorque Operators" 1
(3) 2DLS-15108, dated September 14, 1982, "Limicorque Motor Key Failures in Safety Injection System Valves" (4) DMW-D-3354, dated March 31, 1983, " Sheared Pinion Keys in
(
Limitorque SB-0-25 Motor Operators"
o BEAVER VALLEY POWER STATION - UNIT NO. 2 DUQUESNE LIGHT COMPANY Final Report. on Sheared Pinion Keys in Limitorque Motor Operators 1.
SUMMARY
In complying with the resolution to NRC IE Bulletin 81-02, "Limitorque" operators on valves supplied by Westinghouse Nuclear Energy Systems (WNES) were reworked at the BVPS-2 jobsite.
During disassembly and inspection, six of ten valves with SB-0-25 operators were found to contain sheared pinion keys.
These keys are used to secure the pinion gear to the motor shaft which transmits torque to the operator.
The affected valves are located in the safety injection system (SIS) and function during the recirculation phase of safety injection.
2.
DiMEDIATE ACTION TAKEN WNES was informed about the sheared keys and these were replaced with new keys supplied by WNES.
WNES also filed a 10CFR21 report with the Director of NRC's Region III Office of Inspection and Enforcement.
Duquesne Light Company notified the Region I Office on September 1,
1982, that an evaluation concerning potential reportability of the prob-lem under 10CFR50.55(e) was underway.
Interim Report No. I concerning this issue was submitted to NRC October 7, 1982.
3.
DESCRIPTION OF DEFICIENCY The affected valves are:
WNES WNES Limitorque Operator Motor Item Valve ID Location #
Operator Type Serial #
Serial #
1 10GM72FB 8811A SB-0-25 ft-lb 245153 ID710787-VB 2
10GM72FB 8811B SB-0-25 ft-lb 245150 ID710787-VB 3
10GM72FB 8887A SB-0-25 ft-lb 245152 ID710787-VB l
4 10GM72FB 8887B SB-0-25 ft-lb 245151 ID710787-VB 5
14GM72FB 8809A SB-0-25 ft-lb 248019 ID710787-VB 6
14GM72FB 8809B SB-0-25 ft-lb 248020 ID710787-VB These valves were shop tested to WNES requirements prior to shipment and were not operated after delivery at the site.
A metallurgical evaluation of the failed pinion keys, performed by WNES, l
indicated that they were of a low carbon steel rather than an available hardened alloy.
Prior to identification of the sheared pinion keys at BVPS-2, modifications / inspections of SB-0-25 operators were made by WNES at 32 other plants and only one sheared pinion key was found; however, hardness checks were not made.
The possibility of sheared pinion keys previously identified for Limitorque Model SMB-4 motor operators in was Information Notice 81-08.
Y
4.
ANALYSIS OF SAFETY IMPLICATION As a result of the failure of a pinion key, the open or closed position of the motor operated valves cannot be determined during valve opera-tion.
If the failure was not detected, this would adversely af fect the safety of operation of the plant.
Items 1 and 2 are required to provide a recirculation path from the recirculation pumps to the low head safety injection discharge header.
Items 3 and 4 provide separation of flow paths during recirculation.
Items 5 and 6 provide redundant flow paths from the refueling water storage tank to the suction of the low head safety injection pumps.
All of these functions are critical to the intended safety function of the SIS.
5.
CORRECTIVE ACTION TO REMEDY DEFICIENCIES Westinghouse and Limitorque have now completed an extensive investiga-tion of this issue, and Westinghouse has determined that the pot ent ial for sheared keys is limited to Westinghouse Electro-Mechanical Division (WEMD) manufactured valves equipped with Limitorque Model SB-0-25 motor operators.
Although it has been determined that the unique circumstances resulting in key failure af fect only SB-0-25 motor operators on WEMD manufactured valves, yEMD has elected to replace the pinion keys on all SB-0 series motor operators on yTMD manufactured valves.
or other modifications to the In the course of performing maintenance af fected valves discussed in Section 2 of this report, 'WEMD has replaced the. pinion keys with keys of the correct material and geometry.
6.
ADDITIONAL REPORTS This is the final report.
Duquesne Light Company believes that the i
pinion key replacement outlined above resolves all concerns and provides a final resolution of this issue.
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