ML20084D497
| ML20084D497 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 03/02/1971 |
| From: | Hoyt H COMMONWEALTH EDISON CO. |
| To: | Morris P US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| 71255, NUDOCS 8304120058 | |
| Download: ML20084D497 (2) | |
Text
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v 50-237 Commonwealth Edison Company 72 WEST ADAMS STREET
- C H I C A G O.
ILLINCIS Address R. ply to:
- C H I C A G O, ILLINO44s.0690 Dresden Nuclear Power Station g)
R. R. #1 Morris, Illinois 60450 6~
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s March 2, 1971 i
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Dr. Peter A. Morris, Director N
DI. vision of Reactor Licensing R5 J.S. Atomic Energy Commission Washington, D.C.
20545
SUBJECT:
M ENSE DPR-19, DRESDEN NUCLEAR PO4ER STATION UNIT #2, SECTION 6.6.C.1 OF THE TECFCIICAL SPECIFICATIONS
Dear Dr. Morris:
This is to report a condition relating to the operation of the station in which, on February 3, 1971, 2/3 "A" Standby Gas Treatment System malfuncti.oned.
Problem, Investigntion, ano Corrective Actica Unit #2 was operating and the instrument bus was being switched from auxiliary power to normal power.
During this transfer, a spurious initiation of the Standby Gas Treatment System occurred.
Standby Gas Treatment System train 2/3 "A" was in primary and started but immediately tripped.
"B" train, which was in standby, started following the trip of 2/3 train and operated satisfactorily, p
Investigation revealed that the end bells had come off of the
[
3 2/3 "A" train discharge damper motor operator (MO-2/3-7505-A), preventing f
the damper from opening completely.
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The damper was manually closed and the motor operator taken i
out of service electrically.
All other components remained in service 4
in the event that 2/3 "A" train Standby Gas Treatment System was needed for operation in a manual mode.
Following replacement of the motor end bells a check on motor operator current, (connected to the damper and also disconnected) indicated y
that the motor was drawing excessive amperage indicating a defective j
motor.
Further inspection following disassembly revealed the rotor el-aft to be bent causing the excessive amp rage condition.
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$N
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8304120058 710302 PDR ADDCK 05000237 S
- 0PY SE.NT REG'ON
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Dr. Peter A. Morris Page 2 bbrch 2,1971
'1he damaged motor operator was rebuilt and returned to service February /f, 1971.
Subsequent test operation of the 2/3 "A" train Standby Gas Treatment System was initiated and all components of this train operated satisfactorily.
Tnis same motor operator had malfunctioned on January 5, 1971.
Following repair, the operator was returned to service and was operated normally on seven occasions up to the date of the failure noted in this letter.
As a result of this latest malfunction, the new operator ordered following the January 5,1971, malfunction will be installed ae, a replacement as soon as it is delivered and tF.e present notor operator d isc ard ed.
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H. K. Iloyt Superintendeat ilKil:WPW:dmc
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