ML19321A257

Responds to IE Bulletin 80-05, Vacuum Condition Resulting in Damage to Chemical Vol Control Sys (CVCS) Holdup Tanks. Design Features & Proper Operating Procedures Ensure Adequate Protection Against Vacuum Damage

ML19321A257
Person / Time
Site:	Marble Hill
Issue date:	07/07/1980
From:	Shields S PSI ENERGY, INC. A/K/A PUBLIC SERVICE CO. OF INDIANA
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
IEB-80-05, IEB-80-5, NUDOCS 8007230093
Download: ML19321A257 (2)

Text

. _ _ _ _ _ _ _ _ _ _ _ _ _ _ ___ -__ - __ -____________

1 0703804001

' TD 5" . . .

1 PUBLIC SERVICE  ;

INDIANA S. W. Shields l senior vice Presdent - July 7, 1980 l Nuclear Division l

l Mr. James G. Keppler, Director Docket Nos.: STN 50-546 U. S. Nuclear Regulatory Commission STN 50-547 Region III Construction Permit Nos.:

799 Roosevelt Road CPPR - 170 Glen Ellyn, Illinois 60137 CPPR - 171 Marble Hill Nuclear Generating Station - Units 1 and 2 IE Bulletin 80-05

Dear Mr. Keppler:

In response to IE Bulletin No. 80-05, Public Service Company of Indiana, l Inc., (PSI) has reviewed the design of all systems at Marble Hill that contain low pressure or holdup tanks that can be valved te contain primary system water.

The CVCS volume control tanks and the BRS holdup tank are the only two tanks that receive letdown flow. Both of these tanks operate with a nitrogen cover gas supplied via a header. High and low pressure in the header are annunciated locally, and followed up by an alarm on the main control board that indicates a problem on the local panel. Pressure switch alarms are used to indicate a failure of both the nitrogen supply l package and the bulk storage supply. l During periods of rapid removal of liquid from the tanks cover gas is supplied via a make up path. The control valve associated with this make up path is adequately sized to admit the cover gas at a fast enough rate to keep up with the maximum rate of liquid removal from the tank.

In addition to cover gas protection, other design provisions have been included to prevent vacuum damage. They artt

1. Specification of design pressure rig v vs consistent with tank operating conditions.

2. An external pressure design of 15 psig for the CVCS volume control tank and 10 psig. for the BRS holdup tesk.

jul. 9 198" P.O. Box 190, New Washington, Indiana 47162 812. 293.4441 o ? c 30073 ,

c-

/-

e s' PUBUC SERVICE INCHANA Letter: James G. Kr.ypler July 7, 1980 These design and protection features, in conjunction with proper operating procedures, ensure adequate protection against vacuum damage occuring to these tanks. If you have any questions, please feel free to contact me.

Sincerely, S. W. Shields TDG/cg cc: Director of Inspection and Enforcement U. S. Nuclear Regulatory Commission Washington, D. C. 20555 E. R. Schweibinz, P. E.

J. J. Harrison l

1 l