Method and apparatus for control rod drive mechanism analysis using coil current signals
First Claim
1. A method for analyzing an electromagnetic drive mechanism for a nuclear control rod while positioning the control rod relative to a core of a reactor for controlling nuclear flux during generation of power by the core, the mechanism having at least one stationary gripper and coil, at least one movable gripper and coil, at least one armature and coil for displacing the movable gripper relative to the stationary gripper, and a timing circuit coupled to a coil current driver operable to provide current to said coils in sequences of operations in which said coils are energized individually and in combinations for advancing and retracting the control rod relative to the core, the method comprising:
- positioning the control rod relative to the core of the reactor for controlling said nuclear flux by executing said sequences of operations while;
sensing current signals in said coils during each of said sequences of operations;
sampling and digitizing the current signals of each of said sequences of operations to provide coil current data samples over time;
processing the coil current data samples of each of said sequences of operations to generate coil current data representing a measure of at least one of;
a current amplitude, a time of current amplitude variation indicating a change in coil inductance, and an ac ripple;
defining nominal amplitudes and timing relationships for the coil current signals;
storing at least part of the coil current data of each of said sequences of operations as historical data in a historical log; and
comparing the coil current data of each later one of the sequences of operations to said historical data from earlier ones of the sequences of operations and identifying and indicating deviations therefrom occurring over time.
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Accused Products
Abstract
The electromagnetic drive mechanism for the control rods of a nuclear reactor has a stationary gripper and coil, a movable gripper and coil, and a lifting armature and coil for moving the movable gripper to advance or retract the control rods in steps. A coil current driver responsive to a controller provides currents to the coils individually and in combinations. During the operations, coil current signals are sensed, sampled, digitized and processed to generate coil current data such as amplitude as a function of time. The measured coil current data is compared to nominal current data as well as historical current data, and the historical data is updated or appended to include the measured data. The comparison includes a check for correct timing relationships, such as the timing of the current notch occurring due to increased inductance upon pull-in of a gripper. Additionally, voltages or currents between the ac power source and the coils can be monitored for isolating a failure to particular circuit elements.
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Citations
7 Claims
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1. A method for analyzing an electromagnetic drive mechanism for a nuclear control rod while positioning the control rod relative to a core of a reactor for controlling nuclear flux during generation of power by the core, the mechanism having at least one stationary gripper and coil, at least one movable gripper and coil, at least one armature and coil for displacing the movable gripper relative to the stationary gripper, and a timing circuit coupled to a coil current driver operable to provide current to said coils in sequences of operations in which said coils are energized individually and in combinations for advancing and retracting the control rod relative to the core, the method comprising:
positioning the control rod relative to the core of the reactor for controlling said nuclear flux by executing said sequences of operations while; sensing current signals in said coils during each of said sequences of operations; sampling and digitizing the current signals of each of said sequences of operations to provide coil current data samples over time; processing the coil current data samples of each of said sequences of operations to generate coil current data representing a measure of at least one of;
a current amplitude, a time of current amplitude variation indicating a change in coil inductance, and an ac ripple;defining nominal amplitudes and timing relationships for the coil current signals; storing at least part of the coil current data of each of said sequences of operations as historical data in a historical log; and comparing the coil current data of each later one of the sequences of operations to said historical data from earlier ones of the sequences of operations and identifying and indicating deviations therefrom occurring over time. - View Dependent Claims (2, 3, 4, 5, 6, 7)
Specification