Nuclear Reactor Printed Circuit Card Self-Testing
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Solution Overview
Problem
Existing printed circuit cards in nuclear reactor protection systems are power-intensive, lack adequate status indicators, and require periodic offline testing, making troubleshooting difficult and prone to delayed detection of malfunctions.
Innovation Solution
The development of a printed circuit card with a main CPLD and a test CPLD that allows for continuous self-testing without taking the card offline, using test pulses shorter than the latching period to compare outputs and provide real-time status indicators, reducing power consumption by operating at 3.3 volts and incorporating redundant power supply converters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If existing printed circuit cards operate from a 15 volt power supply, then they can provide sufficient power for logic circuits, but they consume large amounts of power
Solution Approach 1:
The patent changes the operating voltage parameter from 15 volts to 3.3 volts, which directly reduces power consumption while maintaining sufficient power for logic circuit operation through modern low-voltage CMOS technology
2Device complexity
If printed circuit cards lack adequate status indicators, then device complexity is reduced, but troubleshooting becomes difficult
Solution Approach 1:
The patent implements self-diagnostic capability where the card automatically tests itself and provides status information through LEDs and a seven-segment display, enabling the card to report its own health status without external testing equipment
Solution Approach 2:
The patent replaces complex mechanical testing procedures with electronic self-testing circuits that automatically detect faults and display status information, substituting physical troubleshooting actions with automated electronic diagnostics
3Reliability
If periodic offline testing is used to test printed circuit cards, then reliability is maintained, but productivity is reduced due to taking cards out of service
Solution Approach 1:
The patent enables continuous testing while the card remains in service, eliminating the need to take cards offline for testing. The self-test circuit operates concurrently with normal card function, maintaining both reliability verification and system availability
Solution Approach 2:
The patent performs preliminary self-testing before faults can manifest as system failures, continuously monitoring card health and detecting issues early while the card is still operational, preventing unexpected failures
4Reliability
If test pulses are applied to off-line cards for testing, then malfunction detection is achieved, but time is lost due to alternating testing schedules
Solution Approach 1:
The patent transforms periodic discontinuous testing into continuous real-time self-testing, eliminating the six-month testing interval by continuously monitoring card functionality while it operates, thereby detecting faults immediately rather than after extended periods
Data Source
AI summary
A nuclear reactor plant protection system printed circuit card comprises a first logic device having a number of basic logic circuits, and a second logic device operatively connected with the first logic device for testing the number of basic logic circuits without taking the printed circuit card out of service. A nuclear reactor plant protection system printed circuit card comprises a first logic device producing a first output signal in response to a test signal, a second logic device producing a second output signal in response to the test signal, and a comparator for comparing the first output signal and the second output signal, wherein the test signal has a pulse duration that is less than a latching period associated with the printed circuit card. A method of testing and a nuclear reactor control system incorporating the nuclear reactor plant protection system printed circuit card is also provided.