ML19339A309

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Submits Quantitative Evaluation of Effect of Cracks in Core Spray Sys Piping on Water Level Indication.Water Level in Annulus Was Lower than Core Spray Vessel Nozzle
ML19339A309
Person / Time
Site: Oyster Creek
Issue date: 10/30/1980
From: Finfrock I
JERSEY CENTRAL POWER & LIGHT CO.
To: Crutchfield D
Office of Nuclear Reactor Regulation
References
NUDOCS 8011030562
Download: ML19339A309 (1)


Text

Jersey Centra! Power & Light Company

- _DSR JEDH Madison Avenue at Punch Bowl Road Moms?own. New Jersey 07960 (201)455-6200 October 30, 1980 i

A 7

Mr. Dennis M. Crutchfield, Chief Operating Reactors Branch #5 U.S. Nucicar Regulatory Commissic.1 Washington, D. C. 20555

Dear tir. Crutchficid:

As stated in our Juiy 2, 1980 letter, cracks or breaks in the core spray system piping located between the reactor vessel nozzle and core shroud would result in a conservative water icvel indication on 17.6 low-low-low water level sensors. In that letter we agreed to provide a quantitative evaluation of the effect on the water level indication and also to provide the results of that evaluation to you.

Calculations were performed to determine the water icvel in the annulus when the water level in the shroud is at the triple low set point.

Void fractions of 12*6, 34*. and 54*. in the shroud were assumed. The level in the shroud at the triple low set point was then calculated. Assuming static conditions the corresponding level in the annulus was determined.

For each of the void fractions, the water level in the annulus was lower than the core spray vessel nozzle. E.g. , for a 34*. void fraction the level in the annulus is 52 inches below the cora spray vessel nozzle. If there were a guillatine break of the core spray piping between the vessel nozzle and the shroud, the variable leg sensed by the triple low instrumentation would be the level in the annulus. For the void fractions analyzed this would be below the level of detection of the triple low level alarm. For a 34*. void fraction this conservative ir.argin would be 52 inches.

If you have any further questions on this matter, please contact Mr. J. Knubel (201/455-8753) of my staff.

Very truly yours,

):; ^ , /.:,

b-Ivan R. Finfrock, Jr.

Vice President la 8012oao6GA Jersey Centra! Power & Light Company is a Member of the General Pubhc Utiht es System