ML20010G615
| ML20010G615 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 09/11/1981 |
| From: | Nichols T SOUTH CAROLINA ELECTRIC & GAS CO. |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, NUDOCS 8109220313 | |
| Download: ML20010G615 (4) | |
Text
__ n south CAROLINA ELECTRIC a gas COMPANY POST OFFICE 80K 764 CoLUMeA, ScuTH CAROLINA 29218 T.C.Nicuots JR.
September 11, 1981 7
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NWCLEAn Ops.ns ioets a
V' Mr. James P. O'Reilly, Director U. S. Nuclear Rsgulatory Ccmission Region II, Suite 3100
.7 101 Marietta Street, N. W.
g Atlanta, GA 30303 Subject-Virgil C. Sumer Nuclear Station Docket No. 50/395 Reportable Substantial Safety Hazard Pinched Wires in Motor Control Centers Nuclear Eng. File:
3.1051
Dear Mr. O'Reilly:
On Febrmy 4,1981, a potential substantial safety hazard as deff7ed cy 10CFR21 was reported to John Rausch at NRC Region II office.
On March 10, 1981 an interim report was sent to NRC Region II.
On May 4, 1981 the item was upgraded to-a Substantial Safety Hazard and on May 27, 1981 an interim repert was sent to NRC Region II.
The item #;ivolves pinched wire in Square D Co.1E 480 Volt Motor Contr:si Centers.
Details of the Substantial Safety Hazard are found in the attached final report.
Very truly yours, y
T. C. Nichols, Jr.
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James P. O'Reilly Page two September 8,1981 cc: V. C. Suw---
G. H. Fisum.
H. N. Cyrus T. C. Nichols, Jr.
O. W. Dixon, Jr.
D. A. Nauman J. C. Ruoff W. A. Williams, Jr.
R. B. Clary O. S. Bradham A. R. Koon A. A. Smith H. Radin M. N. Browne H. E. Yocom B. A. Bursey J. K. Skolds J. B. Knotts, Jr.
I&E Document Management Branch NPCF File
10CFR - SUBSTANTIAL SAFETY HAZARD 1.
Name and Address of Reporting Individual Tom Brewer South Carolina Electric and Gas Cor.: tany P. O. Box 764 Columbia, SC 29218 2.
Identification of Basic Component 480 Volt Motor Control Center 3.
Identification of Firm Supplying Compoaent Square D Company 252 North Tippecanoe Peru, Indiana 46970 4.
Nature of Defect, Substantial Safety Hazard Created, and Evaluation The problem involves pinching of some stab wires against tie channels in Class 1E motor control centers. There was evidence of pinching, but there has been no failures in Class IE motor control centers.
If the pinched wire was allowed to remain in that condition for a number of years, it is possible that the insulation of the wire could crack or split and cause a fault from the hot lead te ground.
For the worst case analysis, if we assume that all the motor control center cubicals that had a possibility of failing, did fail then we could have lost the following equipment:
1.
DG Room A Exhaust Fan A XFN 0075A-AH 2.
DG Room A Exhaust Fan B XF'l 0075B-AH 3.
DG 1A Diesel Power Panel Xrd 0047-DG 4.
DG 1B Diesel Power Panel XPN 0048-DG 5.
DG Room B Supply Fan B XFN 00458-AH 6.
Service water pump house XFN 0080A-AH supply fan 7.
Service Water Screen Wash XPP 0044B-SW Pump B 5.
Date Information of Defect Was Obtained 6.
Number and Location of Defect Motor Control Centers XMCIDA2Z - Units 4GI, 4JL, 2LM, IGI; XMCIDB2Z - Units 2JM,.'GI, 3DF; XMC-lea 1X Unit IGI; XMC1EB1X
- Units 1GI
4 7.
Corrective Action Square D Engineering and SCE&G inspected the motor control centers for possible pinched wire problems.
Potential problem areas were with units with starter sizes 3 or 4, 225A frame circuit breakers units, and twin FA frame circuit breakers units which are located in the motor control center space beginning with space factors D, G or J.
Units of the above description had a potential of having pinching hetween the back of the MCC can and the tie channel.
The units with potential problems were identified and the units were reassiCaed a new location where there is not possibility of pinched wire. All the electrical modifications are complete. Square D Company has developed a varsion of the tie channel which eliminates the pinched wire problem, but it has not been seismically qualified at this time. Square D Company has said that they intend to qualify the modified version in the next motc, control center seismic test.
8.
Advice to Purchasers or Licensees Purchcse the new motor control center with the new revised tie channel after Square D Co. seismicly tests them.
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