Patent Number: 
Section: claims

1. A nuclear reactor plant protection system printed circuit card comprising:a first logic device having a first input, a first output and a number of basic logic circuits operatively connected between the first input and the first output;a second logic device having a second input, a second output and substantially the same basic logic circuits as the first logic device, operatively connected between the second input and the second output, the second logic device being operatively connected with said first logic device;a test pulse generator operatively connected to the first input and the second input for providing short test pulses for automatically testing said number of basic logic circuits without taking said printed circuit card out of service, the test pulses overriding any other signal at the first input; anda comparator operatively connected to the first output and the second output for comparing a signal at the first output with a signal at the second output and identifying when the signal at the first output does not match the signal at the second output. 2. The printed circuit card of claim 1 wherein said number of basic logic circuits are continuously tested without taking said printed circuit card out of service. 3. The printed circuit card of claim 1 wherein said number of basic logic circuits are tested at least once a second without taking said printed circuit card out of service. 4. The printed circuit card of claim 1 further comprising a third circuit operatively connected with said first logic device and said second logic device, said third circuit structured to permit said first logic device to verify the operation of said second logic device. 5. The printed circuit card of claim 1 wherein said printed circuit card is one of a safeguards driver card, a universal logic card, or an undervoltage driver card. 6. The printed circuit card of claim 1 further comprising a power supply structured to convert a first voltage to a second voltage for use by said printed circuit card. 7. The printed circuit card of claim 1 wherein said first logic device is a main complex programmable logic device and wherein said second logic device is a test complex programmable logic device. 8. A nuclear reactor plant protection system printed circuit card comprising:a first logic device having a number of basic logic circuits structured to produce a first output signal in response to a test signal;a second logic device having a number of basic logic circuits substantially the same as the first logic device, the second logic device being structured to produce a second output signal in response to said test signal; anda comparator for comparing said first output signal and said second output signal;wherein said test signal has a pulse duration that is less than a latching period associated with said printed circuit card. 9. The printed circuit card of claim 8 wherein said test signal is applied to said first and second logic devices and said first and second output signals are compared without taking said printed circuit card out of service. 10. The printed circuit card of claim 8 wherein said printed circuit card is one of a safeguards driver card, a universal logic card, or an undervoltage driver card. 11. The printed circuit card of claim 8 further comprising a test pulse generator and counter structured to produce said test pulse. 12. The printed circuit card of claim 8 further comprising a power supply structured to convert a first voltage to a second voltage for use by said printed circuit card. 13. The printed circuit card of claim 8 further comprising a third circuit operatively connected with said first logic device and said second logic device and structured to permit said first logic device to verify the operation of said second logic device. 14. The printed circuit card of claim 8 wherein said first logic device is a main complex programmable logic device and said second logic device is a test complex programmable logic device. 15. A nuclear reactor control system comprising:a plurality of sensors structured to measure numerous process parameters of a nuclear reactor and to produce a sensor output signal in response thereto;a nuclear reactor protection system having a printed circuit card electrically connected to at least some of said plurality of sensors and structured to receive said sensor output signal from each of said at least some of said plurality of sensors, said printed circuit card comprising:a first logic device having a first input, a first output and a number of basic logic circuits operatively connected between the first input and the first output;a second logic device having a second input, a second output and substantially the same basic logic circuits as the first logic device, operatively connected between the second input and the second output, the second logic device being operatively connected with said first logic device;a test pulse generator operatively connected to the first input and the second input for providing short test pulses for automatically testing said number of basic logic circuits without taking said printed circuit card out of service, the test pulses overriding any sensor signal at the first input; anda comparator operatively connected to the first output and the second output for comparing a signal at the first output with a signal at the second output and identifying when the signal at the first output does not match the signal at the second output. 16. The nuclear reactor control system of claim 15 wherein said number of basic logic circuits are continuously tested without taking said printed circuit cards out of service. 17. The nuclear reactor control system of claim 15 wherein said wherein said number of basic logic circuits are tested at least once a second without taking said printed circuit card out of service. 18. The nuclear reactor control system of claim 15 wherein said printed circuit card further comprising a third circuit operatively connected with said first logic device and said second logic device, said third circuit structured to permit said first logic device to verify the operation of said second logic device. 19. The nuclear reactor control system of claim 15 wherein said printed circuit card is a safeguards driver card, a universal logic card, or an undervoltage driver card. 20. The reactor control system of claim 15 wherein said printed circuit card further comprises a power supply structured to convert a first voltage to a second voltage for use by said printed circuit card. 21. The nuclear reactor control system of claim 15 whereinsaid basic logic circuits of said first logic device include an associated component having a latching period, said latching period being greater than said test pulse duration.