ML20115B490
| ML20115B490 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 03/13/1985 |
| From: | Hufham J TENNESSEE VALLEY AUTHORITY |
| To: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| NUDOCS 8504180032 | |
| Download: ML20115B490 (2) | |
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1 TENNESSEE VALLEY AUTHORITY CHATTANOOGA. TENNESSEE 374ot 400 Chestnut Street Tower II
$ 1A,7198Jg BLRD-50-438/84-47 BLRD-50-439/84-43 U.S. Nuclear Regulatory Canmission Region II Attn:
Dr. J. Nelson Grace, Regional Administrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323
Dear Dr. Grace:
BELLEFCNTE NUCLEAR PLANI UNITS 1 AND 2 - POTENTIAL FOR COOLER FAN FAILURE DUE TO UNERSIZED THERMAL OVERLOAD RELAY HEATER ELEENTS - BLRD-50-438/84-47, BLRD-50-439/84 SECOND INTERIM REPORT The subject deficiency was initially reported to NRC-0IE Inspector P. E. Fredrickson on August 21, 1984 in accordance with 10 CFR 50.55(e) as NCR BLN EEB 8417 Our first interim report was submitted September 19, 1984.
Enclosed is our second interim report. We expect to sulxnit our next report on or about May 24, 1985.
If you have any questions, please get in totch with R. H. Shell at FTS 858-2688.
Very truly yours, TENNESSEE VALLEY AUTHORITY f
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e J. W. Hufham, Manager Licensing and Regulations Enclosure oc:
Mr. James Taylor, Director (Enclosure)
Office of Inspection and Enforcement U.S. Nuclear Regulatory Cecruission Washington, D.C.
20555 Records Center (Enclosure)
Institute of Nuclear Power Operations 1100 circle 75 Parkway, Suite 1500 Atlanta, Georgia 30339 8504180032 850313 PDR ADOCK 05000438 S
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An Equal Opportunity Employer
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' EN(LOSURE
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,-l BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2
- POTENTIAL FOR COOLER FAN FAILURE DUE TO UNDEIE]2ED THERMAL OVERLOAD RELAY HEATER ELEENTS BLRD-50-438/84-47, BLRD-50-439/84-43 10 CFR 50.55(e)
NCR BLN EEB 8417 SECOND INTER 1N REPORT t
Description of Deficiency In nonconformance report (NCR) WBN NEB 8408 (WBRD-50-390/84-35, WBRD-50-391/84-31), TVA identified a deficiency at Watts _Bar Nuclear Plant (WBN) in which three engineered safety feature (ESP) cooler fan motors failed to start during
- preoperational test W-3 1F (integrated safety injection (SI) and station blackout). The failure to start was attributed to in-line thermal overload relays which had tripped. This conditionihad previously occurred at WBN on preoperational test TVA-9C. The'probableicause of these failures has inen attributed to undersized thermal overload: relay heater elements.
Since Bellefonte Nuclear Plant (BLN) uses the same motor control center (MCC) vendor (ITT-Gould) and uses the same vendor sizing criteria, there exists a potential for the same problem to occur at BLN.
Interim Progress TVA has completed a design study which identified and evaluated overload heater sizing in Bellefonte Nuclear Plant (BLN) heating, ventilation, and air-conditioning (INAC) circuits. Based on the data obtained frcra the design-study and TVA Design Guide DGE-2.3.5, TVA determined that increasing the heater size to one size above vendor recommendations would provide adequate overload protection and adequate assurance would be given that the affected safety load would operate during accident conditions. As such, design drawing changes are in progress to maize overload heaters.
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