Nuclear instrumentation isolated output signal scaling method and system employing same

1. A method of determining a core design parameter of a nuclear reactor, the method comprising:

utilizing a detector connected to an input to a Nuclear Instrumentation System (NIS) cabinet, wherein the NIS cabinet isolates a signal from the detector;

calibrating an isolated voltage output from the NIS cabinet associated with the nuclear reactor, wherein calibration provides a range of inputs from a calibrated signal source as an input to the NIS cabinet;

measuring a corresponding voltage output by the NIS cabinet resulting from each calibrated input from the range of inputs;

recording values of the calibrated signal source used in the calibrating of the isolated voltage output and the resulting corresponding values of the voltage output in an as-left cabinet calibration data table;

using a computing device connected to the isolated voltage output from the NIS cabinet, converting the isolated voltage output signal from the NIS cabinet to a converted detector signal using at least some of the values in from the previously determined as-left cabinet calibration data table in an improved signal conversion equation, wherein the improved signal conversion equation uses the calibration information from the NIS cabinet stored in the as-left cabinet calibration table; and

using the computing device, employing the converted detector signal to solve an equation to determine the core design parameter, wherein the core design parameter is indicative of reactivity measurements for the nuclear reactor.

2. The method of claim 1 , further comprising comparing the measured core design parameter to a predicted core design parameter to determine if the measured core design parameter is within an acceptable limit.

3. The method of claim 2 , further comprising determining from the comparing that the measured core design parameter is not within the acceptable limit of the predicted core design parameter and taking a corrective action in response thereto.

4. The method of claim 1 , wherein the calibrated signal source comprises a calibrated current source.

5. The method of claim 4 , wherein the converted detector signal comprises a converted detector current signal.

6. The method of claim 5 , wherein solving an equation using the converted detector signal comprises solving the Inverse Point Kinetics Equation using the converted detector current signal and one or more additional nuclear design constants as inputs.

7. The method of claim 1 , wherein determining a core design parameter comprises determining at least one of Isothermal Temperature Coefficient, Boron Endpoint or Control Rod Worth.

8. The method of claim 1 , wherein the calibrated signal source comprises a calibrated current pulse source.

9. The method of claim 8 , wherein the converted detector signal comprises a converted detector pulse signal.

10. The method of claim 1 , wherein the computing device comprises a reactivity computer.

11. The method of claim 1 , wherein the isolated voltage output from the NIS cabinet corresponds to the input received by the NIS cabinet from a source range detector monitoring the nuclear reactor.

12. The method of claim 1 , wherein the isolated voltage output from the NIS cabinet corresponds to the input received by the NIS cabinet from an intermediate range detector monitoring the nuclear reactor.

13. The method of claim 1 , wherein the isolated voltage output from the NIS cabinet corresponds to the input received by the NIS cabinet from a power range detector monitoring the nuclear reactor.

14. A computer device adapted to:

receive an isolated voltage output from a Nuclear Instrumentation System cabinet (NIS) cabinet, wherein the NIS cabinet isolates a signal from a detector connected to an input of the NIS cabinet, wherein the isolated voltage output from the NIS cabinet associated with a nuclear reactor is calibrated, wherein calibration provides a range of inputs from a calibrated signal source as an input to the NIS cabinet, wherein a corresponding voltage output by the NIS cabinet resulting from each calibrated input from the range of inputs is measured, and wherein the values of the calibrated signal source used in the calibrating of the isolated voltage output and the resulting corresponding values of the voltage output in an as-left cabinet calibration data table are recorded;

convert the isolated voltage output from the NIS cabinet to a converted detector signal using at least some values from the previously determined as-left cabinet calibration data table in an improved signal conversion equation created from a previously carried out calibration of the isolated voltage output using a calibrated signal source as an input to the NIS cabinet, wherein the improved signal conversion equation uses the calibration information from the NIS cabinet stored in the as-left cabinet calibration table; and

determined determine a core design parameter by using the converted detector signal to solve an equation, wherein the core design parameter is indicative of reactivity measurements for the nuclear reactor.

15. The computing device of claim 14 , wherein the computing device is further adapted to compare the core design parameter to an expected core design parameter.