US 5,211,904 AGranted

In-vessel water level monitor for boiling water reactors

AssigneeGeneral Electric Company

InventorWillem J. Oosterkamp

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Abstract

Apparatus and method are described for providing a discrete readout of the collapsed water level within a boiling water reactor. An elongate gauge housing is mounted within the reactor vessel extending through the collapsed level from a steam environment into a boiling water environment. A serially coupled sequence of junction defining thermocouple element pairs are positioned within the gauge housing and are arranged with a heating assembly to generate an output signal which corresponds with the water level. Also located under the influence of the heating assembly are reference thermocouples, one providing a reference output corresponding with the instantaneous temperature of the boiling water environment and the other providing a reference output corresponding with the steam environment above the collapsed water level. The signals from the reference thermocouples and the serial coupled level determining thermocouple structures are then treated to define instantaneous water level.

Claims17

Dependent claims

Apparatus for determining the level of water within a boiling water power generator having a steam environment above said level and a saturated or slightly subcooled water environment below said level, comprising:

an elongate gauge housing mounted to extend substantially vertically through said steam environment, through said water level and into said boiling water environment and having an opening therein for receiving said water to an elevation corresponding with said level
thermocouple means including a serially coupled sequence of junction defining thermocouple element pairs positioned within said gauge housing for generating an output signal of amplitude corresponding with said water level;
first reference thermocouple means mounted within said generator and having a lengthwise extent selected for substantially continuous immersion within said water environment, for deriving a water reference signal independent of said output signal;
second reference thermocouple means mounted within said generator and having a length selected to position at least a portion thereof to extend above said water level within said steam environment for deriving a steam reference signal independent of said output signal;
heater means extending from a predetermined upper location above said water level within said steam environment to a predetermined lower location within said water environment, positioned in select heat transfer association with said level responsive thermocouple means, said first reference thermocouple means, and said second reference theremocouple means, for deriving select temperature differentials across said level responsive thermocouple means;
and
signal treatment means responsive to said output signal, said water reference signal and said steam reference signal for deriving a readout of value corresponding to said water level.

4 more elements

The method for determining the level of water within a boiling water power generator vessel having a steam environment above said level and a saturated or slightly subcooled water environment below said level, comprising the steps of:

providing a sequence of electrically serially coupled, junction defining thermocouple element pairs of successively increasing lengthwise extent;
foldably configuring said thermocouple element pairs in a parallel, mutually adjacent vertical orientation wherein alternate said junctions commencing with the first said junction of said sequence are located at a common, predetermined base level within said vessel, and wherein alternate said junctions commencing with the second said junction are each located at a predetermined unique level within said vessel spaced from said base level;
positioning a heating component within said vessel adjacent to and in a thermal exchange relationship with said thermocouple element pairs;
applying heat to said thermocouple element pairs from said heating component through and under the heat dissipating influence of said steam environment above said water level and under the heat dissipating influence of said water environment below said water level;
detecting the amplitude of voltage output of said sequence of thermocouple element pairs;
and
correlating said detected amplitude with a calibration value to derive the position of said level of water within said vessel.

4 more elements

providing a substantially linear sequence of electrically serially coupled, junction defining thermocouple element pairs from first to last;
positioning said linear sequence of thermocouple element pairs vertically within said vessel extending from within said steam environment into said water environment;
providing a heating assembly formed as a linear sequence of mutually spaced discrete heating components from first to last;
providing a water reference thermocouple within said vessel at a location within said water environment selected for substantially continuous immersion;
providing a steam reference thermocouple within said vessel at a predetermined location having at least a portion within said steam environment;
positioning said heating assembly within said vessel such that a respective said discrete heating component, from first to last, is located in thermal exchanging adjacency with a select portion of respective first to last thermocouple element pairs, said water reference thermocouple and said steam reference thermocouple;
applying heat to said thermocouple element pairs from first to last from said respective heating components through and under the heat dissipating influence of said steam environment above said water level and under the heat dissipating influence of said water environment below said water level to establish a differential of temperature across each said thermocouple element pair, said heat application being to a portion of said water reference thermocouple from said respective heating component to derive a water reference signal and to a portion of said steam reference thermocouple from said respective heating component to derive a steam reference signal;
detecting the amplitude of an output signal generated by said linear sequence of thermocouple element pairs, said water reference thermocouple and said steam reference thermocouple;
and
correlating said detected amplitude with said water and steam reference signals to derive the position of said level of water within said vessel.

7 more elements

Dependencies are inferred from the claim text.