ML20072L082
| ML20072L082 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 07/08/1983 |
| From: | Kemper J PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, 84, NUDOCS 8307130015 | |
| Download: ML20072L082 (3) | |
Text
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.3 2830573100 PHILADELPHIA ELECTRIC COMPANY l
2301 M ARKET STREET a
i P.O. BOX 8699 PHILADELPHI A, PA.19101 (215)841 4502 JOHN S. MEMPER JUL 8 1983
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E Li.nerick Cenerating Station Units 1& 2 rinal Significant Deficiency Feport #84 Defect in Motor Operated Valve Tanden Torque Switchen Julv 5, 1983 1.0 Introduction
~his in the final report regnrding a nignificant deficiency on notor operated volves with tanden torque switches nuppiled to Limerick Cencrating Statien (ICS) by Linitoroue Corporation.
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Dercription of Prohlren Approximtcly 250 nafety-related notor operated valven (tf0V) havn tanden torque cultches to control the t'OV'n in each direction of valve travel.
Preoperational tenting has nhown that the tanden switch assenbly contains rechanical " play" in the linkage shaft couplinqn a llovirq.*ngular rotation of one cwitch anecnbly with reduced novement transferred to the othar switch annenb1v. This "plav" causes one of the electrically paralleled torcue rwitch co9 acts to ranain closed after tha other torque switch han opa a d at the prescribed satting.
This will allow the retor to continue to onorata, thereby couning valvo sten damage and/or notor, burnout.
3.0 Analvsin of Problon A natorials test lab exanination and terting of a tanden torque
- r. witch analyend that the coupling plev allnwed approximately 10 decreer of shaft rotation batween the innar and euter torcun rwitches.
Thia resultn in 1) late operation of the outer torque evitch an if the toroue nottinq in higher than indicated, or ?) non-operatina. of the outer torque switch renulting in notor burn out or dmnage to the valve eten.
4.0 Eafety Inplications A torque switch risoperation could result in operator noter failura and nechanical danage cauring a nefety related valve to become inoperable.
This nituation exietn for all rafetf related valve notor operatorn sine SMP-0 and larger.
The lo w of one notar operated valve would not adverselr affect the capability to achieve e cafo chutdown of the piant.
However, the safe operation of Linerick could have been co7rnnised if nultiple failuren were to occur ninultaneounty and this condition had gone uncorrected.
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t 2830573100 5,0 Corractiva Action i
'"h n abcvn deficiency is being corrected bv renoving one of the
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torque :witchan in each tanden a s r,enbl y.
Thin modification will reconfigure thn torque rwitchan to the Linitsrquo etandard configuration.
r All nodificationn to the Unit Cro valve notor oparators will be
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co~pleted by December 31, 1993.
The no<lificatforn to thn Ur. i t Two operators will be conpleted prior to Unit Two ruel Lond.
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