Controlling the response of a pressurized water reactor to rapid fluctuations in load
AssigneeWestinghouse Electric Corp.
InventorGary D. Storrick
Life of this patent
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Abstract
The setpoints for control systems in a pressurized water reactor are adjusted by an amount corresponding to the expected change in the controlled process variable resulting from rapid fluctuations in load to reduce the duty time of the control system components such as the rod drive mechanisms in the rod control system and the spray and heater units in the pressurizer pressure control system. In addition, the deadband in the response of the rod control system is continuously varied as a function of the variance of the magnitude of the rapid fluctuations in load to further reduce wear while maintaining good response during load following.
Claims31
Apparatus for controlling the response to a load signal of a pressurized water reactor having a plurality of controlled process variables, said apparatus comprising:
- a control system for effecting control actions to regulate a selected process variable to a value called for by a setpoint reference signal;
- and
- means responsive only to rapid fluctuations in said load signal above a predetermined frequency for adjusting the value of said setpoint reference signal by an amount which substantially matches the variation in the value of the selected process variable expected as a result of said rapid fluctuations in the load signal without control action, and taking into account any time delay in the affect of the rapid fluctuations on the selected process variable, whereby control actions effected by said control system are substantially reduced.
A method of operating a pressurized water reactor having a plurality of control systems controlling a plurality of process variables, said method comprising the steps of:
- generating setpoint signals for said control systems;
- operating said control system to effect control actions which regulate the associated process variables to the value called for by the associated setpoint signal;
- generating a load signal representative of the load imposed on the reactor;
- generating from said load signal a rapid fluctuation signal representative of the magnitude of fluctuations in the load signal above a predetermined frequency;
- and
- adjusting the magnitude of at least one of said setpoint signals in response to said rapid fluctuation signal by an amount which substantially matches the change in the value of the associated process variable expected as a result of said rapid fluctuations in the load signal without control action, taking into account any time delay in the affect of the load change on the value of the associated process variable, whereby the control actions required by the associated control system are significantly reduced.
Apparatus for controlling the response of a pressurized water nuclear reactor, having control rods for controlling the reactor power level, to rapid fluctuations in a load signal representative of the load imposed on the reactor, said apparatus comprising:
- rod control means responsive to the load signal for positioning the control rods to regulate the power level of the reactor to the power level called for by the load signal, and including means for generating a deadband in the response of the control rods to changes in the magnitude of the load control signal by inhibiting repositioning of the control rods when the change in magnitude of the load signal is smaller than a selected change in magnitude such that the reactor adjusts to such small changes in load imposed thereon through changes in operating temperature;
- and
- deadband adjusting means for varying the value of said selected change in magnitude of the load signal defining said deadband as a function of the magnitude of fluctuations in the load signal above a predetermined frequency, whereby the width of the deadband in the rod control means is varied with the magnitude of the rapid power changes resulting in a significant reduction in the control actions required by the rod control means.
Apparatus for controlling the response to a load signal of a pressurized water nuclear reactor having control rods for regulating the power level of the reactor said apparatus comprising:
- deadband signal generating means responsive to said load signal for generating a deadband control signal as a function of the magnitude of fluctuations in the load signal above a predetermined frequency;
- reference means for generating a temperature reference signal from said load signal;
- and
- rod control means response to the magnitude of the temperature reference signal (T.sub.REF) for positioning said control rods and including deadband control means responsive to said deadband control signal for inhibiting the response of the control rods to the temperature reference signal (T.sub.REF) when the difference between actual temperature and the temperature called for by the temperature reference signal is less than said deadband control signal, whereby the deadband in the response of the control rods to changes in the load signal varies as a function of the magnitude of rapid load changes resulting in a significant reduction in the control actions required by the rod control means.
A method of operating a pressurized water nuclear reactor having control rods for regulating reactor power in response to a load signal representative of the load imposed on the reactor including the steps of:
- positioning the control rods as a function of the change in magnitude of the load signal when the magnitude of such change exceeds a selected value, such than there is a deadband in the response of the control rods to changes in magnitude of the load signal which causes the reactor to respond to changes in magnitude smaller than the selected value through a change in reactor operating temperature;
- and
- varying said selected value as a function of the magnitude of fluctuations in the magnitude of the load signal above a predetermined frequency whereby positioning of the control rods is substantially reduced.
Dependencies are inferred from the claim text.