Development of maintenance and trouble shooting for nuclear instrumentation system

To increase the safeguards and availability factor of nuclear power plants, periodic preventive maintenance procedures, inspections and adjustments, for all assemblies of the Nuclear Instrumentation System (NIS) must be performed. To remove expeditiously and exactly the faulty area of operation from the system when NIS malfunctions, the test troubleshooting and test procedure must be established. Thus, considering the troubleshooting procedure of NIS for Kori plant unit 1 and the test procedure of IEEE Standard, the structure of each system and the input/output characteristics of each circuit were analyzed. Analyzing the waveforms and the amplitudes of the input/output of each block circuit under all operation conditions, the troubleshooting and test procedures for source range of NIS are established. And also developing the troubleshooting technique using logic circuit for isolation amplifier which was manfactured for trial, the foundation for troubleshooting procedures using microprocessor is prepared. (author)