ML19256F013
| ML19256F013 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Byron, Braidwood, Quad Cities, Zion, LaSalle  |
| Issue date: | 10/26/1979 |
| From: | Peoples D COMMONWEALTH EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| IEB-79-23, NUDOCS 7911160564 | |
| Download: ML19256F013 (2) | |
Text
T/ C- -
Commonwealth Edison One First National Plaza. Chicago. Illinois Address Reply to: Post Office Box 767 Chicago, lihnois 60690 October 26, 1979 Mr. James G. Keppler, Director Directorate of Inspection and s
Enforcement - Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137
Subject:
Dresden Station Units 1, 2, and 3 Quad-Cities Station Units 1 and 2 Zion Station Units 1 and 2 LaSalle County Station Units 1 and 2 Byron Station Units 1 and 2 Braidwood Station Units 1 and 2 Response to IE Bulletin 79-23
" Potential Failure of Emergency Diesel Generator Field Exciter Transformer" NRC Docket Nos. 50-10/237/249, 50-254/265, 50-295/304, 50-373/374, 50-454/455, and 50-456/457 Reference (a):
J. G.
Keppler letter to B.
Lee, Jr.
dated September 12, 1979.
Dear Mr. Keppler:
Reference (a) transmitted IE Bulletin 79-23 which requested a response within 45 days far all power reactor facilities with an operating license or construction permit.
A review of the circuitry for the emergency diesel generators at our facilities indicates that the potential transformers used for voltage regulation and field excitation do not have a common neutral with the generators and are not grounded, there is no connection between the generator windings and the exciter control circuit through the grounding system or otherwise, and for some installations there is no excitation transformer in the exciter circuitry.
It is our conclusion that the problem identified in IE Bulletin 79-23 is not applicable to our units.
The emergency diesels at Dresden 2 and 3, Quad-Cities and Zion are routinely tested at rated load for varying lengths of time.
In all cases, the test duration is of sufficient length to allow stabilization of operating temperatures, which demonstrates the adequate functioning of the cooling systems.
Based on the 1342 293 7911160 h
bed
Commonwealth Edison A.
Mr. James G.
Keppler: October 26, 1979 numerous successful tests in the past and the fact that the problem identified in IE Bulletin 79-23 does not exist, additional 24-hour tests at Dresden 2 and 3, Quad-Cities, and Zion are not considered necessary.
As stated in the FSARs for LaSalle, Byron, and Braidwood Stations, and as currently planned for the new Dresden Unit 1 HPCI and ESAP diesel generators, preoperational tests of the emergency diesel generators will be performed in accordance with Regulatory Guide 1.108.
These tests have already been successfully completed for Diesel Generator lA at LaSalle County Station.
Please address any additional questions you may have concerning this matter to this office.
Very truly yours, Ll( 'l p
i l
- , / ji
.s D.
L.
Peoples Director of Nuclear Licensing RFJ:mae cc:
Director, Division of Reactor Operations Inspection 1342 294