ML20073R270
| ML20073R270 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 04/15/1983 |
| From: | Wells D DETROIT EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, EF2-62625, NUDOCS 8305030596 | |
| Download: ML20073R270 (2) | |
Text
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6 Donald A. Wells
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l April 15, 1983 EF2-62625 Mr. James G. Keppler, Regional Administrator Region III U.S. Nuclear Regulatory Cmmission 799 Roosevelt Road Glen Ellyn, Illinois 60137
Subject:
Interim Report of 10CFR50.55(e) Item on Rosanount Trip Units
(#75)
Dear Mr. Keppler:
This interim report on the Rosamount Trip Units has been prepared to provide the current status of this problem.
This item was originally reported to Mr. J. Konklin of NRC Region III by Detroit Edison's Mr. G.M. Trahey, Assistant Director - Project Quality Assurance, on July 20, 1982.
Durug calibration of Rosemount bbdel 510 DU Trip Units, it was determined 2
that a high percentage could not be calibrated. Without circuit analysis, Edison Engineering was unable to determine whether or not, if uncorrected, the problan would prevent the unit fran performing its function properly.
Based on preliminary evaluation, the cause was believed to be oxidation of the trip set point adjusting potentianeter windings. Further investigation revealed that Rosemount had manufactured those potenticmeters with silver contacts. Edison is currently replacing them with potentiometers contain-ing gold contacts.
Another report on this item, either interim or final, will be sent when fur-ther information is available. If you have questions concerning this matter, please contact Mr. G.M. Trahey, Assistant Director - Project Quality Assur-ance.
Very truly yours, a.a wdL DAW /DF/pn
[h 8305030596 830415 PDR ADDCK 05000341
. APR 2 7 1983 S
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Mr. James G. Keppler, Regional Administrator April 15, 1983
,J Page 'I%o EF2-62625 4
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cc: Mr. Richard DeYoung, Director I
Office of Inspection and Enforecment U.S. Nuclear Regulatory Comnission i
Washington, D.C.
20555 i
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Mr. Bruce Little, Senior Resident Inspector U.S. Nuclear Regulatory Ccunission j
6450 North Dixie Highway Newport, Michigan 48166 i
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