ML19351D634

Part 21 Rept Re Beloit Power Sys Generator Losing Field. Caused by Lead Between Collector Rings & Field Coils Shorting to Rotor & Burning in Two Pieces at Point of Short. Insp of Another Generator Showed Frayed Insulation

ML19351D634
Person / Time
Site:	Summer
Issue date:	09/22/1980
From:	Moriarty J COLT INDUSTRIES, INC.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
REF-PT21-80-286-000 NUDOCS 8010140343
Download: ML19351D634 (2)

Text

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E.D. Greene ,

September 22, 1980 hggHa ey t G. Olson J.W. Tangye l Office of Inspection & Enforcement R. Koons, BPSI

!' U.S. Nuclear Regulatory Comission 799 Roosevelt Road Glen Ellyn, Ill. 60137 Attention: Mr. James G. Keppler, Director, Region III l

Subject:

Colt Industries-Fairbanks Morse Engine Division Emergency Diesel Generators

! South Carolina Electric & Gas Co.-Sumer Station 5a-M6 Part 21 Report - Beloit Power Systems Generators 3 Possible Field Insulation Damage Gentlemen:

i This is to confirm our verbal report (R.H. Beadle to D.W. Hayes) of September 19, 1980.

A Beloit Power Systems generator in commercial service at Sitka, Alaska lost its field because a lead between the collector rings and the field coils shorted to the rotor and burned in two pieces at the point of the short. Subsequent

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examination of anoth.er generator of identical design at the same installation

showed frayed insulation at a clamp (same location as the burn through) which

secures the lead to the rotor.- This unit was operating satisfactorily but if the insulation damage were to progress the possibility of grounding the lead to ,

the rotor exists. ,

To detennine if the problem might exist at other locations our chief electrical engineer was sent to Provo, Utah which has four generators of identical design.

.He has reported by phone that two of the four at Provo have frayed insulation

-at the clamp but that there was no indication of loss of field.

Concurrent with our inspection at Provo, Beloit Power Systems was asked to evaluate the cause of frayed insulation and also if any other generators might have the same problem. Their verbal report to us is that the cause of fraying is poor workmanship in installation of the clamps and that there.are other generators of identical design in this area. Specifically the eight generators shipped

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to Limerick where poor wo(Philadelphia Electric) are of the identical design in the area rkmanship is known to have caused a problem.

Our plan is to inspect the Limerick generators and repair any poor workmanship which may be found.

Beloit Power Systems a,lso reports verbally that the design in this area for 5 and 6 frame alternators has been similar for a number of years and it is therefore possible that the problem may extend to operating units.

The list of Fairbanks Horse Model 38TDC-1/8 OP generator sets equipped with 5 or 6 frame Beloit Power Systems generators is as follows; W- . ,l"3

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l Office of Inspecticn & Enforcement '

.U.S. Nuclear Regulatory Comission Glen Ellyn, Ill. September 22, 1980

l. 1 Unit -

2665 KW for Northeast Utilities, Millstone Nuclear Plant - Unit fl.

2. 2 Units - 2500 KW for Carolina Power & Light, Robinson Nuclear Plant.

3. 2 Units - 3000 KW for florthern States Power, Prairie Island Nuclear Plant.

4. 2 Units - 3000 KW for Vermont Yankee Corp., Vermont Yankee 'Juclear Plant.

5. 2 Units - 3000 KW for Metropolitan Edison, Three Mile Island Nuclear Plant fl.

6. 4 Units - 3250 KW for Philadelphia Electric Co., Peachbottom Nuclear Station

1. 2 & f3.

7. 3 Units - 3250 KW for Baltimore Gas & Electric Company, Calvert Cliffs Nuclear Stations #1 and #2.

8. 2 Units - 3000 KW for Florida Power Corporation, Crystal River No. 3

9. 2 Units - 3000 KW for Jersey Central Power and Light Company Three Mile Island Nuclear Station No. 2

10. 3 Units - 3250 KW for Georgia Power Company, Hatch Nuclear Fiant fl.

11, 2 Units - 3250 KW for Iowa Electric Light & Power Co., Duane Arnold Nuclear Plant.

12, 4 Units - 3000 KW for Virginia Electric & Power Co., North Anna Nuclear Plant #1 & f2.

13. 2 Units - 3250 KW for Northeast Utilities, Millstone Nuclear Plant - Unit f2.

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14. 2 Units - 3250 KW for Alabama Power Company, Farley Nuclear Plant Units il & #2.

15 2 Units - 3250 KW for Arkansas Power & Light Company, Arkansas Nuclear One -

Unit f2.

16. 2 Units - 3250 KW for Georgia Power Company, Hatch Nuclear Plant f2 (with option for additional unit).

17. 4 Units - 3250. KW for Detroit Edison Company, Enrico -Femi #2.

18. 8 Units - 3250 KW for Philadelphia Electric Company, Limericak Nuclear Station il & #2.

It is suggested that'the generator field leads be inspected for insulation dama0e at the clamps attaching these leads to the generator rotor.

A conference call with NRC duty officer, Personnel from Prairie Island Nuclear Plant R.H. Beadle, and C. Evenson of Beloit Power Systems was arranged for 9:30 AM 9/20/80 so that the method of inspection could be explained and taped for use by the NRC in explaining the inspection required to other sites. Mr. Evenscn was the spokesman and described the method of inspection to visually check for insulation distress at clamps and for clearance between generator field leads and the generator fan.

Edited written instructions covering the inspection method have been requested of Beloit Power Systems. We will contact NRC upon receipt to discuss method of distribution.

Very truly yours,

, .H. Moriarty MAtlAGER UTILITY SA ES JMM/jl -

cc: U.S. Nuclear Regulatory Comission ~

c/o Document Management Branch Washington, D.C. 20555

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