ML20084K088
| ML20084K088 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 03/15/1972 |
| From: | Stephenson B COMMONWEALTH EDISON CO. |
| To: | Morris P US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20084K079 | List: |
| References | |
| AO-1-72-3, NUDOCS 8305190142 | |
| Download: ML20084K088 (2) | |
Text
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( $om m e mwealtil Edison Comimiiv QUADClfif$ NUCLtAR Powt e STATION
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Ad+en neply to Po%T OFFICE box 216
- CORooVA. ILLINots 61242 March 15. t v/2
[> r. Peter A. Morris, Director Division of Reactor Licensinq 50-2~i1 O!4
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U.S. A omic Encrqy Commission t
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Washington, D.C.
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SUBJECT:
DPR Quad Ci t ics Nuclear Power S tation Uni t I i
REFERENCE:
Appendix "A" to UPR Sect ions 6.6A.3 & 6.68.2
Dear Dr. Morris:
As set forth by the Technical Specifications for Quad Cities Nuclear Power Station in Section 6.6A.3 and 6.68.2, the following abnormal occurrence is reported as incident Number 1-72-3.
OCCURRENCE On March 10, 1972 at 7: 30 p.m., the reactor manual control system was energized in the " REFUEL" mode for a series of surveillance tests.
The nuclear station operator was unable to obtain a control rod with-draw permissive.
Investigation of the problem indicated the following relay coils burned out:
REFERENCE:
Sargent & Lundy Drawing 4E-lkl4 107 - Rod Select Permissive 108 - Rod in Permissive 121 - Refuel Mode Auxili ur 124 - Refuel Equipment Rt. 4ut :
,ek Auxi1iary 126 - Service Platform Fuel Loaded Auxiliary 127 - Scram Discharge Volume Hioh Level g
K Rod Worth Minimizer Output Buf fer tj,1 j j K Rod Worth Minimizer Output 3uffer K Rod Worth Minimizer Output Buf fer
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Or. F eter A. Morris, Lirector March 15, 1972
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The cause of the overexcitation and burnout was due to the f c l iow i r.g even t s.
The retractable cable on the Unit 1 - refueling b-idoc was ceing replaced with a lorger cable and during the re-placenent some wiring changes were made so that the (as built) drawings conformed with the manufacturers drawings. The retractable cable is 12 conductor with 11 conductors used. The work was done by craft electricians under the direction of the General Electric Company using Commonwealth Edison Company "out of service and modification procedures (Ref. - flodi ficat ion 285-1-72). A wirinq error was made which i mros ed 277 vo l t s ( 480 vo l t system-phase to ground) on a normal 120 volt circuit. The system was energized before the work was checked out and tested because it was not p roper ly t aqqed '9 ut -O f -Se rvi ce". Without the "out of service procedure" the communication link to all shift supervisors was brnkan, they were not informed that the work was going on.
This action was a s iolation of our onerat ino nror.edures and could have rendered the systen in an unsafe condition.
Corrective Action All relays in the associated branches of the reactor manual control system were checked for DC resistance and ground resistance.
All defective relays were replaced and some wiring in the rod worth minimizer buffer was replaced.
The original preoperational test A-6
" Control Rod Drive Manual Control was nerformed on the system followed by normal pre-start surveillance tests.
All work groups were retrained on our 'Out-of-Service" procedures and their importance relating to safety of personnel and equipment.
Sincerely yours, COMMONWEALTH EDISON COMPANY Quad-Ci t ies Nuc lear Power S tat ion
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B.B.Ste/henson BBS/zm
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