ML20003A273
| ML20003A273 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 04/23/1974 |
| From: | James Shea US ATOMIC ENERGY COMMISSION (AEC) |
| To: | |
| References | |
| NUDOCS 8102030378 | |
| Download: ML20003A273 (2) | |
Text
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1 U'e UNITED OTATE3 V)g ATOMIC ENERGY COMMISSION
' 'l WASHINGTON. D.C. 20$ IS April 23, 1974
%n e Files (Docket No. 50-155)
I THRU:
. p.
iemann, Chief, ORB #2, L d
N/E Www--
W TELECON RECARDI REMOVAL OF THE FOUR LOWER ROLLERS FROM ONE CONTROL
, BLADE (CONSUMERS POWER COMPANY - BIG ROCK POINT PLANT)
By letter dated April 1,1974, Consumers Power Company (CPCo) informed the Directorate of Licensing of its intention to remove the four lower rollers on one peripheral control rod blade during the current April 1974 partial refueling outage and observe the effects on continued operation of the rod. In the past, some of the rollers on other blades have broken off and the necessity for them is being reevaluated by GE and CPCo. Of the possible corrective measures reviewed, permanent removal of the lower blade rollers appears to be the most attractive according to CPCo.
This April 9,1974 telecon supplements information presented in the referenced letter. The following statements were made by the CPCo representative.
1.
Base line measurements on the selected control rod performance were made prior to shutdown to compare with similar measure-ments af ter the bottom rollers are removed.
2.
During the next year of operation, there will be frequent measurements to detect any measurable changes in behavior cha racteris tics.
3.
During the next refueling outage (expected during the summer of 1974 when the M0 fuel assemblies are to be inserted), the control rod blade will be removed and inspected for evidence of rubbing, wear, twisting, or misalignment.
4.
It is expected that during one fuel cycle (normally about 1 year) the modified control rod blade, to be located in the core periphery and normally fully withdrawn during operation, will be scram tested about four times and experience about ten startups and shutdowns; i.e., withdraw - insert cycles.
5.
CE has recommended removal of the lower rollers because they are
[
(s, not required.
I R
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Files April 23, 1974 b
g" The blade water hole gap is 0.7 inch.
6.
A V
The roller is 0.475 inch in diameter.
Tne blade sheath thickness is 0.3 inch.
Additional lateral blade movement possible with rollers remc-d is one-half of 0.175 inch. This increased lateral movement.
not enough to change buckling potential significantly.
We plan no further consideration of the referenced letter.
gJ t(,C
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James J. She
>perating Reactors Branch #2 Directorate of Licensing cc: Consumers Power Company AEC PDR K. R. Coller, L:0R T. J. Carter, L:0R D. L. Ziemann, L:0RB #2 J. J. Shea, L:0RB #2 R. M. Diggs, L:0RB #2 Ro (3) o cc
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