ML20094D748
| ML20094D748 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 07/23/1984 |
| From: | Jens W DETROIT EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 61, EF2-69284, NUDOCS 8408080511 | |
| Download: ML20094D748 (2) | |
Text
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[ Wayne H. Jens U
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Vice Prevdent Nc! ear Operanons m
Fernw-2 6400 North Due Hfway
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July 23,.1984 L
EF2-69284 m,
Mr.~ James G.
Keppler
-Regional Administrator Region III U.
S. Nuclear Regulatory Commission p.
799. Roosevelt Road
~
Glen Ellyn,- Illinois 60137'
Dear Mr. Keppler:
Reference:
(1) Fermi 2 NRC Docket No. 50-341 (2) Letter, D..A.
Wells to J.
G.
- Keppler,
-April'9, 1982, EF2-57462
Subject:
Final Report of.10CFR50.55(e) Item 61
" Undersized Battery Cables" This Lis Detroit Edison's final report concerning undersized ba ttery.' ca bles.
Item 61 was originally reported as a potential deficiency on March 12, 1982, and subsequently documented. in.: Re ference (2).
M Description of the' Deficiency During a review of the DC System at degraded voltage conditions,. it was discovered.that some cables were m undersized.' The' undersized cables fell into two major 7
categories:
1.
LPower Cables to Motor Operated Valves The ~ cable ' size did not allow for voltage drops encoun-3
-tered during. locked rotor currents as the motor started and.p.ior to the operation.of the valve torque
. switches.
Analysis of these circuits indicated voltage levels at the valve motors were below the starting
. voltages required for the valve motors.
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.Mr. James G.
Keppler
' July =23, 1984 EF2-69284-Page 2 E
- 2. :
iControl' Circuits to Remotely Located Switchgear:
The cable size and length did not allow for voltage drops, associated with currents required to ensure
- proper' operation of the trip and closing coils in the Jaffected switchgear.
' Analysis of Safety Implications
. Undersized cables may not have provided sufficient voltage f
.to ensure. operation of the affected switchgear and motor U
operated valves.
Corrective Action De troit Edison conducted an analysis of all DC motor control center ' cables L and switchgear control cables to locate those cables that ;were undersized -for the intended service.. The
~
-modifications consist of the following:
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o Design changes were issued which require larger size cables for the af fected motor operated valves.
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o LDesign' changes were initiated to install inter-posing relays in the trip /close circuits of the affected-swltcngear.
These relays will ensure
'that the minimum voltage at the trip /close coils
- e is adequate for reliable operation.
Field work associated with the above design changes is in y.
.the' final stages of completion.
This is ' Detroit Edison's final report' on this item.
(
q.
.If you'have' questions concerning this matter, please contact
- f
' Mr. Lewis P.
Bregni, (313) 586-5083.
em Sincerely, q
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Mr.. R.
C..DeYoung 6M4 cc:Mr.
P. / M.
Byron Mr.
R.
C.
Knop E
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