ML20010C475
| ML20010C475 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 08/10/1981 |
| 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 8108200117 | |
| Download: ML20010C475 (2) | |
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August 10, 1981 L
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-Mr. James P. O'Reilly, Director NE*'0" ['
'U. S. Nuclear Regulatory Commission g
.y Region II, Suite 3100 b
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101 Marietta Street Atlanta,.GA. 30303
Subject:
Virgil C. Summer Nuclear 2tation Docket No. 50/395 Significant Deficienc Final Report l
I Daar Mr. O'Reilly:
c On May 29, 1981, Mr. Virgil Brownlee of NRC Region II was notified of a potential significant deficiency or potential substantial safety hazard on the subject: Mounting Brackets on Transformer Found Broken After Installation.
An Interim Report was filed on June 29, 1981. On July 24, 1981, Mr. Paul Kellogg was notified that :he potential item was upgraded to a significant deficiency.
The item is being reported under 10CFR50.55(e) procedure and the details of the item are described in attached report. This is considered a final report on the matter.
Very truly yours, T. C. Nichols, Jr.
TCN:tdh i
cc:
V. C. Summer H. N. Cyrus C. H. Fischer J. B. Knatts E. H. Crews J. L. Skolds
- 0. W. Dixon B. A. Bursey C. A. Price O. S. Bradham D. A. Nauman Document Management Branch W. A. Williams ~
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8106200117 810810 PDR ADOCK 05000395 S
e 10CFR50.55(e) - SIGNIFICANT DEFICIENCY r
~1.
Identification of Nonconformance A new Westinghouse inverter cabinet with a transformer enclosed was being installed when an electrical maintecarce technician noticed that the transformer was being supported only by it's connecting wires.
Inspection showed that all four mounting brackets were broken at the 90 degree bend. The bending radius of the 90 degree bend was very small and the bracket broke smoothly along this sharp bend. The broken brackets were ont discovered in the initial receiving because the transformer was inside the cabinet, which has no access doors.
The inverter system was not out of service because of the bracket problem. The broken brackets were found and replaced before the inverter system was placed back in operation.
2.
Number and Location of Nonconformance Inverter cabinet XIT-5902 3.
Significant Deficiency Created and Evaluation Postulating the worst accident condition the broken brackets could result in failure of 7.5KVA inverter (XIT-5902). This inverter is the main feed to the Engineering Safety Feature vital 120 volts AC instrument panel #2.
Thus, the broken brackets could have cau+ad temporary loss of 120 volt AC instrument panel #2 on the Nuclear Safety Related channel A.
Safety channel B would not be affected.
4.
Corrective Action Mounting brackets from the old transformer that was being replaced by the new transformer vare removed and installed on the new transformer. The new transformer is identical to the old transformer.
Since the old transformer and brackets were seismically qualified, the new transformer and the same brackets are seismically qualified.
Maintenance work requests were written to inspect the five other inverter cabinets, XIT-5901, XIT-5903, XIT-5904, XIT-5907, and XIT-5908 to look for broken brackets.
No other broken brackets were found.
Westinghouse's plant representative was notified of the broken bracket problem and he reported it back to their bracket designers for consideration of generic problems.
SCE&G suspects that the brackets broke in shipment to Summer Station and no corrective action on the part of SCE6G to prevent recurrence is considered necessary.