ML20148E928
| ML20148E928 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 10/31/1978 |
| From: | Andognini G BOSTON EDISON CO. |
| To: | Ippolito T Office of Nuclear Reactor Regulation |
| References | |
| 78-183, NUDOCS 7811070185 | |
| Download: ML20148E928 (2) | |
Text
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g DOETON EOlBON COMPANY GCNERAL OrrscEs 800 BDYLsTON STREET B D sTD N, M As sAcNustTTs D 2199 G. CARL ANDDGNINI MANAGER HUcLEAR DPERATIONs DEPARTMENT Oc.ober 31, 1978 BECo. Ltr. #78-183 Mr. Thomas A. Ippolito, Chief Operating Reactors Branch #3 Division of Operating Reactors Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D. C.
20555
Dear Mr. Ippolito:
Picase find attached a ccpy of the memo I agreed to send summarizing the unusual operating history of the "B" diesel-generator at Pilgrim Station.
If I can be of any further assistance, please let me know.
Very truly yours, 4 />4 a
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Attachment
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NOD #78-728 OFFICE MEMORANDUM 3
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RECORD CATEGOR Y-To Mr. J. E. Howard Pmpeed by Miss S. J. Little /
October 26, 1978 Rw'M by
- 1 Dme PNPS FILE NUMBER Nucteer Records Center Approved by Mr. G. Carl Andognini 6.12 Thie:
Pilgrim "B" Diesel Generator
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The recent failure of the "B" diesel-generator stator initiated a review of its l
operating history in order to determine if the failure could be attributed to
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specific occurrences or if it could be indicative of a generic problem. The L
conclusion derived from this review is that "B" diesel-generator experienced f
three unique situations that resulted in abnormal stresses being applied to the l
unit.
"A" diesel-generator has not experienced similar conditions.
Therefore,
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the evidence at hand supports the conclusion that the failure of the "B" stator i
is not a generic problem, but is unique to that diesel-generator.
t A brief summary of the three instances involving the "B" diesel-generator are presented as follows:
1.
In the early part of 1972, during pre-op testing, the "B" diesel-generator was inadvertent.ly backscuttled (i.e. 4 kV applied to the stator with the unit at stand-still) when an operator manually closed the bus-to-diesel breaker (#152-609).
The unit tripped on overcurrent.
2.
On July 30, 1974, the "B" diesel was running when the 125 VDC supply to the engine controls was lost. The operator was consequently un-j able to shutdown the unit and a voltage regulator failure resulted.
The diesel-generator tripped on overspeed.
3.
On August 2, 1978, the "B" diesel-generator was synchronized on line out of phase which re.sulted in a voltage regulator failure and a subsequent trip.
A more detailed description of these instances is available at Pilgrim, and will be provided upon request.
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cc: Messrs. P. J. McGuire l
R. D. Machon G. C. Andognini-File 6.12
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I t-CECs Form 3855
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