Detection of core thermal hydraulic oscillations
AssigneeCombustion Engineering, Inc.
InventorLionel A. Banda
Life of this patent
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Abstract
A plurality of neutron flux sensors (44,46,48,50) and a corresponding plurality of gamma flux sensors (62,64,66,68) are distributed throughout axial zones (24,26,28,30) of the core (14) at the same or closely proximate locations. A steady state comparison, or bias, between the signals of a given neutron/gamma sensor pair are monitored (314, 316), and a divergence (or convergence) can readily be detected through simple signal filtering, to detect a shift in the bias. The pattern of significant convergence and divergence throughout the core, is indicative of the thermal hydraulic stability of the core.
Claims22
A method for detecting thermal hydraulic oscillation in a nuclear fission reactor core through which a reactor coolant passes while the fission reactions in the core generate neutrons and gamma radiation, comprising the steps of:
- positioning a first plurality of sensors, which are primarily responsive to neutron flux, at a respective plurality of first locations in the core;
- positioning a second plurality of sensors, which are primarily responsive to gamma radiation flux, at a respective plurality of second locations in the core;
- generating an output signal from each of said neutron sensors, commensurate with the neutron flux at each neutron sensor;
- generating an output signal from each of said gamma sensors, commensurate with the gamma radiation flux at each gamma sensor;
- comparing each neutron sensor output signal with a respective gamma sensor output signal and generating a comparison value signal for each of said comparisons;
- and
- in response to the comparison value signals generating output data indicative of core thermal hydraulic oscillations.
A method for detecting thermal hydraulic oscillations parallel to the axis of the core of a boiling water nuclear reactor, comprising the steps of:
- sensing at each of a plurality of axially spaced apart zones within the core, changes in the local neutron flux and gamma flux;
- and
- from said sensed changes, generating output data indicative of incipient thermal hydraulic oscillations in the core.
A system for monitoring thermal hydraulic oscillations in a boiling water nuclear reactor, comprising:
- a plurality of a first type of sensor spatially distributed in the core, said first type of sensor having a first time dependent output signal, commensurate with the density of reactor coolant over a short range during the generation of power in the reactor core;
- a plurality of a second type of sensor spatially distributed in the core, said second type of sensor having a second time dependent output signal which, relative to the first type of sensor, is commensurate with the density of the coolant over a long range during power operation of the reactor core;
- means for associating each of said first type of sensors with one of said second type of sensors, to define a plurality of sensor pairs;
- means for generating a third output signal commensurate with a quantitative relationship between the first and second output signals from the sensors in each pair, thereby defining a plurality of paired time dependent measurement values;
- and
- means responsive to the paired measurement values, for generating output data indicative of thermal hydraulic oscillations in the core.
Dependencies are inferred from the claim text.