ML20059C337

Advises That Util Plans to Remove Some Thimble Plugging Devices from Plant During Upcoming Refueling Outage.No License Amend Required.Revs to Tech Spec Bases 3/4.2.2 & 3/4.2.3 That Reflect All Removal of Thimble Plugs Encl

ML20059C337
Person / Time
Site:	Callaway
Issue date:	08/23/1990
From:	Schnell D UNION ELECTRIC CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20059C339	List: ML20059C337 ML20059C341
References
ULNRC-2274, NUDOCS 9008310203
Download: ML20059C337 (3)

Text

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Eucenue r"~*"'

.j g August 23, 1990 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Station P1-137 ,

Washington, D. C. 20555 Genticmon: ULNRC-2274  ;

DOCKET NUMBER 50-483 CALLAWAY PLANT THIMBLE PLUG REMOVAL During the upcoming refueling outage (Refuel 4),

Union Electric plans to remove some of the thimblo plugging devices from che Callaway Plant. A safety evaluation por ,

10CFR50.59 has boon performed to support the complete or partial removal of the thimble plugs. No licenso amendment is required; however, the attachment contains revisions to Technical Specification Bases 3/4.2.2 and 3/4.2.3 that reflect an all-VANTAGE 5 core with the thimbic plugs removed.

The main effect of thimble plug removal is an increase in the core bypass flow. For the callaway Plant, removal of all of the thimble plugging devices causes the design value of the core bypass flow to increase from 6.3%

to 8.6%. This increase in bypass flow can be accommodated by the allocation of 3.1% DNBR margin. With an all VANTAGE 5 core (i.e., no transition core DNBR penalty), there is more than sufficient DNBR margin built into the existing Callaway safety analysos to absorb this penalty.

l If you have any questions on the attached Bases l changes, please contact us.

Very truly yours,

. /

Donald F. Schnell 9008310203 900823 PDR ADOCK 05000403 L e 0000'1 P PNV s /

010 GGY/sla i l\ \

STATE OF MISSOURI )

) SS CITY OF ST. LOUIS )

Donald F. Schnell, of lawful ago, being first duly sworn upon oath says that he is Senior Vice President-Nuclear and an officer of Union Electric Company; that he has road the foregoing document and knows the content thereof; that he has executed the same for and on behalf of said company with full power and authority to do so; and that the facts therein stated are true and correct to the best of his knowledge, information and belief.

m By / / _,

' Donald F.Schholl Senior Vice President Nuclear SUBSCRIBED and sworn to before me thi.s d 8AAday of d , 1990.

/ AW. b41l BAltDAR , I'f AF NOTARY PUBLIC, STATE OF MISSOURI MY COMMISSION EXPIRES APRIL 22. 1993 ST. LOUIS COUNTY

d . - - -

4 cci .T.RA.-Baxter, Esq.

Shaw, Pittman, Potts & Trowbridge 2300.N. Street, N.W.

Washington, D.C. 20037

,Dr. J. O. Cermak CFA,-Inc.

4 Professional Drive (Suite 110)

Gaithersburg, MD 20879 R .- C . Knop Chief,. Reactor Project Branch 1 U.S. Nuclear Regulatory Commission Region III 799 Roosevelt Road.

Glen Ellyn, Illinois 60137 Bruce Bartlett Callaway_ Resident Office

.U.S. Nuclear Regulatory Commission

, RR#1 Steedman, Missouri 65077 -

Anthony T. Gody, Jr. (2)

Office of Nuclear Reactor Regulation U.S. Nucient Regulatory Commission

'l White Flint, North, Mail Stop 13E21 11555 Rockville Pike Rockville, MD 20852 l 1

Manager,. Electric Department Missouri Public Service Commission i P.O. Box 360 *

' Jefferson City, MO 65102  ;

Ron Kucera Department of Natural Resources l P.O. Box 176-Jefferson City, MO 65102 j 1.

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