ML20093M157
| ML20093M157 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 10/04/1984 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| NCR-2815, NUDOCS 8410190419 | |
| Download: ML20093M157 (2) | |
Text
r-L TENNESSEE VALL'EY AUTHORITY
- CHATTANOOGA.l TENNESSEE s74ol
'400 Chestnut Street Tower II
~ BLRD-50-439/84-15 U.S. Nuclear Regulatory Commission.
Region II Attn:
Mr. James P. O'Reilly, Regional Administrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia ~ 30323
Dear Mr. O'Reilly:
BELLEFONTE NUCLEAR PLANT UNIT 2 - DEFECTIVE AMPLIFIERS IN SAFETY-RELATED PANELS MANUFACTURED BY EL-TEX - BLRD-50-439/84 FINAL REPORT The subject. deficiency was initially reported to NRC-0IE Inspector P. E. Fredrickson on February 14, 1984 in accordance with 10 CFR 50.55(e) as NCR 2815. This was followed by our interim reports dated March 5 and June 28, 1984.. Enclosed is our final report.
Please note that TVA does not now consider the subject nonconforming condition adverse to the safe operation of the plant. Therefore, we will amend our records to delete the subject nonconformance as a 10 CFR 50.55(e) item.
If you have any questions, please get in touch with R. H. Shell at FTS 858-2688.
Very truly yours, TENNESSEE VALLEY AUTHORITY L. M. Mills, nager Nuclear Licensing Enclosure cc: Mr. Richard C. DeYoung, Director (Enclosure) i Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Records Center (Enclosure)
Institute of Nuclear Power Operations 1100 Circle 75 Parkway, Suite 1500 Atlanta, Georgia 30339 8410190419 841004 l
PDR ADOCK 05000457 S
PDR OFFICIAL COPY s
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l ENCLOSURE o
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BELLEFONTE NUCLEAR PLANT UNIT 2 DEFECTIVE AMPLIFIERS IN SAFETY-RELATED PANELS MANUFACTURED BY EL-TEX BLRD-50-439/84-15 NCR 2815 10 CFR 50.55(e)
FINAL REPORT Description of Deficiency All DC isolation amplifiers in electrical panels 2EU-EDP-52A-E and 2EU-EDP-51A-E were found to be defective. These amplifiers are powered by a 125V AC supply, and send a 0-3 milliamp (ma) signal to the main control room indicators which show the status of the class 1E 125V DC power distribution system. This system provides power to various essential safety-related switches such as the 6.9 kV,13.8 kV, and 480V switchgear.
The failure of the amplifiers has resulted in a wide open (i.e., maximum 3 ma) output to the indicators, regardless of the input signal. This results in erroneous indications in the control room on the status of the 125V DC system.
Safety Implications TVA has determined that the failure of the subject amplifiers could not have resulted in a failure of or an unnecessary challenge to the plant safety systems. The amplifiers are only used to provide control room indication on the status of the 125V do power distribution system. This is not a safety-related function which, if lost, could adversely affect the safe operation of the plant.
TVA no longer considers 10 CFR 50.55(e) applicable to this item; however, we did request the vendor (El-Tex Industries, Incorporated, Baltimore, Maryland) to perform an analysis to determine the cause of the failures.
El-Tex informed TVA that their supplier (Scientific Columbus) could not perform the analysis. TVA subsequently sent two cf the defective amplifiers to TVA's Central Laboratory in Chattanooga for analysis. It was i
determined that the failures were caused by a defcotive output filter-capacitor in the power supply of each unit. Age degradation contributed to this failure.
The failed devices have been repaired and will be used as spares. The subject amplifiers have been entered into the Bellefonte Nuclear Plant (BLN) site maintenance procedure (BNP-QCP-1.3) for periodic testing and replacement of the devices every 5 to 7 years as necessary. No other i
problems of this type have been identified at BLN or any other TVA nuclear I
plant.
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