ML20010H424

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Second Revised Deficiency Rept Re 480-volt Motor Control Ctr Control Transformer,Initially Reported 800808.Installation of Bussman Type Jhc 15 & 30 Fuses Complete.Mod of Fuse Holders Unnecessary.Also Reported Per Part 21
ML20010H424
Person / Time
Site: Bellefonte  Tennessee Valley Authority icon.png
Issue date: 09/15/1981
From: Mills L, Mills Lm
TENNESSEE VALLEY AUTHORITY
To: James O'Reilly
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
REF-PT21-80 10CFR-050.55E, 10CFR-50.55E, NCR-1234, NUDOCS 8109240446
Download: ML20010H424 (2)


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52h- O f TENNESSEE VALLEY AUTHORITY-CH ATTANOOGA. TENNESSEE 37401 400 Chestnut Street Tower II

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Mr. James P. O'Reilly, Director kfg Office of Inspection and Enforcement Q % '

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U.S. Nuclear Regulatory Commission -l Region II - Suite 3100 6'f

101 Marietta Street (7Ej Sh@? t ko d .<.,/

Atlanta, Georgia 30303

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Dear Mr. O'Reilly:

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BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 - 480V MCC CONTROL TRANSFORMER FUSES - NCR 1234 - SECOND REVISED FINAL REPORT The subject nonconformance was initially reported to NRC-0IE Inspector M. Thomas on August 8,1980 in accordance with 10 CFR 50.55(e). This was followed by our interim reports dated September 8 and October 24, 1980 and our final report on December 16, 1980. We consider 10 CFR Part 21 to be applicable to this nonconformance. Our first revised final report was submitted June 26, 1981. As discussed with R. V. Crlenjak .by talephone on September 4, 1981, enclosed is our second revised final repor'. c The reason for the revision is to change the type of replacement fuses.

If you have ag questions concerning this matter, please get in touch with D. L. Lambert, at FTS o n-2581.

Very truly yotes, TENNESSEE VALLEY AUTHORITY L. M. Mills,L Manager Nuclear Regulation and Safety Enclosure cc: Mr. Victor Stello, Jr., Director (Enclosure)

Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, DC 20555 b

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8109240446 810915~.

PDR ADOCK 05000438 O PDR An Equal Opportunity Employer

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ENCLOSURh BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 480V CONTROL TRANSFORMER FUSES NCR 1234 10 CFR 50.55(e)

SECOND REVISED FINAL REPORT Description of Deficiency The motor control centers (MCC) at Bellefonte were supplied by Gould-Brown Boveri, Westminster, Maryland. The SkVA and 10kVA control transformers for these MCC's utilize 15- and 30-amp type J fuses, respectively. These fuses have operated when the control circuit is energized. These fuses were not properly chosen to coordinate with the inrush current.

Safety Implications The transformers supply power to 120V Class IE control circuits. If the fuses operate, any equipment that is controlled by those circuits is inoperable. The fuses operate when the circuit is initially energized or when energized after an outage. Therefore, if these circuits are require 1 to energize to mitigate an accident, the associated equipment may not be available, which could adversely affect plant safety.

Corrective Action A subsequent reevaluation by the vendor, Brown Boveri Electric, has determined that Bussman type JHC 15 and JHC 30 will properly protect the SkVA and 10kVA control power transformers without necessitating a modification of the fuse holders. TVA has reviewed and approved this recommendation. Installation of these Bussman fuses is complete.

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