ML20095B659
| ML20095B659 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 08/08/1984 |
| From: | Jens W, Jens W DETROIT EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| REF-PT21-84-414-000 94, EF2-69655, PT21-84-414, PT21-84-414-000, NUDOCS 8408220209 | |
| Download: ML20095B659 (3) | |
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Vee Prevdent Wcrear Oremons Ferms-2 64(y) North Ocue Hrghway n ot33 ras.4tso j
Newport, Michgan 48166 I
August 8, 1984 EF2-69655 Mr. James G. Keppler Regional Administrator Region III U.
S.
Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137
Dear Mr. Keppler:
Reference:
(1) Fermi 2 NRC Docket No. 50-341 (2) Letter, D. A. Wells to J.
G. Keppler, dated May 27, 1983, EF2-63505
Subject:
Final Report of 10CFR50. 55(e) Item 94
" Loose Pole Piece Wedges on Four Emergency Disesel Generators" This is Detroit Edison's final report concern ng loose pole piece wedges on four emergency diesel generat ors.
This item was originally reported as a potential 10 CFR50.55(e) deficiency on April 29, 1983, and was subsequently documented in Reference 2.
Description of Deficiency During initial operation, Emergency Diesel Generator #14 exhibited excessive vibration and was shut down.
Inspection revealed that one of the generator's salient poles had shifted in the axial direction.
The dovetail of the pole projected about 3/ 4" beyond the end of the dovetail slot in the rotor.
The tapered wedges used to lock the dovetail into the slot were loose and could not be tightened.
Further inspection of this generator and the three other diesel generators revealed thirteen additional loose wedge pairs which could not be tightened.
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I Mr. James G. Keppler August 8~
1984 EF2-69655 Page 2 The manufacturer, Beloit Power Systems Division of Litton Industries, identified two probable causes for the loose-pole piece dovetail wedges:
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The wedge-material was too soft for the application.
2.
The wedges were too short to' effectively lock the pole pieces in place.
The Beloit Power Systems Division of Litton Industries notified' Detroit Edison on June 13, 1983 that they had filed this deficiency in accordance with 10CFR21.
Analysis of Safety Implications If the loose pole piece dovetail wedges had gone undetected, this condition could have rendered one or more of the Emergency Diesel Generators inoperable.
Corrective Action The dovetail wedges on all four Emergency Diesel Generators were replaced with wedges made from a harder material.
The new wedges are longer. which. permits them to be driven farther. into the dovetail-slot for a tighter fit.
The installation was performed under the direction of the manufacturer's representative.
After the installation of the new wedges, an overspeed trip was performed on each Emergency Diesel Generator.
All wedges were checked for slippage and were found acceptable.
I Dovetail wedge position verification is now part of the
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_ preventive maintenance program (6 month cycle) for these generators.
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Mr.-James G. Keppler August 8, 1984 EF2-69655 Page 3 This is Detroit Edison's final report on this item.
If you have questions concerning this matter, please contact Mr. Lewis P.
Bregni, (313) 586-5083.
Sincerely, cc:- Mr. P.
M.
Byron Mr.
R.
C.
DeYoung Mr.
R.
C. Knop i
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