ML20084D986

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Advises That Submittal of Rept Re Possible Uncoupling of Three Control Rod/Control Rod Drives Delayed Until 730615 Due to Heavy Outage Work Load on Unit 3
ML20084D986
Person / Time
Site: Dresden, 05000000
Issue date: 05/08/1973
From: Worden W
COMMONWEALTH EDISON CO.
To: Anthony Giambusso
US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084D897 List:
References
3214, 370-73, NUDOCS 8304130130
Download: ML20084D986 (1)


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50-237 Commonwealth Edison Company DNE F8MST NATIONAL PLAZA

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IL LI N OI S Im.e.v, POST OFFICE 805 Fe7

  • CHICAGO, BL&lNOll 40690 Dresden Nuclear Power Station R. R. #1

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.V A. Ciambusso 3

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Deputy Director for Reactor Projects 0.h Directorate of Licensing U.S. Atomic Energy Comnission Washington, D.C.

20545 SUlWECT: License DP&l9 Dresdon Nuclear Pcwer Station. Unit 2 Apparent Uncouplin;: Control l',cd Drives

Reference:

Letter to lir. Giambusso fro:a W. P. Worden dated !! arch 13, 1973.

Dear Mr. Ciambusso:

In our March 13 letter to you (Reference 1) concerning a possible uncoupling of 3 Unit 2 control rod / control rod drives, we informed you that we would submit a report describing the results of the disassembly and inspection of the 3 drives by approximately April 30, 1973.

he heavy outage work load on Dresden Unit 3 has delayed the complete disassembly and inspection of these drives. However, the drives have been removed from Unit 2 and replaced with spare drives. A preliminary inspection of the drives during removal has revealed that two drives apparently had an improperly installed inner screen which could have resulted in drive uncoupling.

Investigation to determine the cause of the apparent uncoupling has continued through meetings with General Electric Company. As a result of this investigation, it is our conclusion at thic time that there are no safety impli-cations. Control rod uncoupling cannot occur at any position other than position 48 (fully withdrawn) because interference between the drive uncoupling rod and mislocated inner screen can only occur at the fully withdrawn position.

We disassembly and inspection of the 3 drives is presently in progress.

It is expected that we will complete our inspection and submit a rep'stt to you on or about June 15, 1973.

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