ML20086P970
| ML20086P970 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 02/02/1984 |
| From: | Kemper J PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| 94, NUDOCS 8402270401 | |
| Download: ML20086P970 (3) | |
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PHILADELPHIA ELECTRIC COMPANY 2301 M ARKET STREET P.O. BOX 8699 PHILADELPHI A, PA.19101 FEB 2 1984 JOHN S. M a'* APE R VIC E-PR ESID E NT ENfs0 NEE RING AND RE55 ARCH Mr. Thomas E. Murley, Director United States Nuclear Regulatory Commission Office of Inspection and Enforcement, Region I 631 Park Avenue King of Prussia, PA 19406
SUBJECT:
Significant Deficiency Report #94 Final Report on Defective DC Motor Control Center Auxiliary Contacts Limerick Generating Station, Units 1 and 2 NRC Construction Permits Nos. CPPR-106 & 107
REFERENCES:
(1)
Telecon of November 15, 1983 P. K. Pavlides (PECO) to W. Baunack (USNRC)
(2)
Potential Significant Deficiency Report of Decerter 16, 1983 FILE:
QUAL 2-10-2 (SDR #94)
Dear Mr. Murley:
In compliance with 10CFR50.55 (e), enclosed is the final report on the subject deficiency.
Sincerely, f S)bf Copy to-Director of Inspection and Enforcement United States Nuclear Regulatory Ccmmission Washington, DC 20555 S. K. Chaudhary, Resident NRC Inspector- (Limerick)
J. Wiggins, Pesident NRC Inspector (Limerick)
DDC/la lal27841210 Enclosure Copy to:
W. C. McDaniel, Bechtel J.
P. Evans E. R. Klossin, Bechtel R. L. Harper V. S. Boyer G. B. Hutt/ Local File E. J. Bradley J. S. Kemper G. T. Brecht, Jr.
R. J. Lees J. J. Clarey R. A. Mulford J. M. Corcoran P. K. Pavlides J. J. Crews E. F. Sproat D. C. Dunn H. R. Walters/ Local File Project File (DAC NG-8) 1 8402270401 840202 h
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Philadelphia Electric Company February, 1984 Limerick Generating Station Units 1 and 2 j
Significant Deficiency Report #94 Defective Auxiliary Contacts in Westinghouse DC Motor Control Centers Final Report l
1.0 Introduction This is the final report regarding a significant performance deficiency involving contact alignment and spring compression in Westinghouse Electric Corporation Type W 125/250 volt direct current motor control center auxiliary contacts.
The Limerick project uses these contacts in both class IE and non-Class IE systems.
The motor control centers were delivered to Limerick station during August 1980.
The USNRC was previously notified of this deficiency in a November 15, 1983 telecon between P.
K.
Pavlides of Philadelphia Electric Company and W.
Baunack of USNRC Region I and also in the Potential SDR of December 16, 1983.
2.0 Description of Problem During preoperational testing of 125/250 VDC MCC contactors, many auxiliary contacts were found to be misaligned and/or had insufficient spring tension to close adequately.
A survey of 20 MCC cubicles resulted in finding 55 of 58 button type contacts with unacceptable alignment and 31 of 58 contacts with unacceptable contact pressure in the normally closed condition.
The measurements were performed in accordance with Westinghouse Electric Corporation in-structions that require the following:
(1) At least 90% mating surface between the contacts.
(2) At least 3/32' compression of the contact spring.
3.0 Analysis of Deficiency The poorly mated contacts and the insufficient contact spring tension are conditions that are adjustable and correctable in the field.
The significant number of deficiencies indicate that there may have been insufficient adjustment and quality control at the Westinghouse plant.
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-Page 2 of 2 4.0 Safety Implication
'An open or poor contact in the auxiliary contact circuits, could result in the failure of DC motor operated valves in the High Pressure Coolant Injection (HPCI) and Reactor Core Isolation Cooling (RCIC) systems to operate correctly.
Since the HPCI and the RCIC systems are-part oflthe emergency core cooling system and primarr ontainment and reactor vessel isolation control and are used for safe shutdown of the plant, failures of the subject DC MCC contacts could cause an adverse effect on the safe operation of the plant.
5.0 Corrective Actions All,of the auxiliary contacts 1: the Westinghouse 125/250 VDC motor control center contactors will be field tested and, where necessary, adjusted for proper conta:.:t surface mating and pressure.
All deficiencies will be corrected by June 1, 1984.
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