ML19291B889
| ML19291B889 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 10/30/1979 |
| From: | Counsil W NORTHEAST NUCLEAR ENERGY CO. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| IEB-79-23, NUDOCS 7912140022 | |
| Download: ML19291B889 (1) | |
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L a = ' C,12,"J = 0; October 30, 1979 Docket No. 50-423 Mr. Boyce H. Grier, Director Region I Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 AEC-MP3-195
Reference:
(1)
B. H. Grier letter to W. G. Counsil dated September 12, 1979.
Gentlemen:
Millstone Nuclear Power Station, Unit No. 3 I&E Bulletin No. 79-23 Reference (1) transmitted the subject I&E Bulletin to Northeast Nuclear Energy Company (NNECO), and requested NNECO to investigate the potential for failure of the emergency diesel generator excitation transformers. An investigation has been completed and the results indicate the type of failure described in the subject bulletin cannot occur on the Millstone Unit No. 3 emergency diesel genera-tors.
Specifically, the excitation power transformers (EPT's) are connected to the diesel generators with a delta primary winding.
The secondary winding is an ungrounded wye.
This configuration will preclude zero sequence, or circulating, currents such as those described in the subject bulletin.
Since Millstone Unit No. 3 is in the construction permit stage, it would be pre aature to provide a schedule for a 24-hour sustained full load test.
Such testing, as required, will be a part of plant pre-operational testing, etc.,
when the appropriate time arrives.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY
/
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$1 W. G. Counsil Vice President
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.s u 7912140 O2
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