Development of Remote Monitoring System at Spent Fuel Storage Silo

A remote monitoring system at spent fuel storage silo of Wolsong-1 was developed with optical fiber scintillating sensors to measure gamma ray and neuron to verify spent fuels to maintain the continuity of knowledge. Series of tests show that optical fiber is enough to be used for spent fuel verification with many advantages over conventional sensors. Measurement of optical fiber sensors that is radiation volume (count value) for spent fuel verification is transferred to the monitoring station. Due to the site’s condition and constraints such as limited space and existing hardware, transmission system was developed to adopt radio frequency to ease any conflict of installation of system. It has following characteristics. Because of the limited memory size of main computer, we developed the high-speed count module (comparator) for calculating the Radiation volume rapidly. The purpose of the comparator compares the actual value to threshold value before A/D (Analog to Digital). The effectiveness of the comparator reduces the storage data and the unnecessary data was deleted before A/D by way of hardware. This module is connected to the RF (Radio Frequency: transmitter) parts and the other RF (receiver) is received the transmission data and the Data storage computer stored the Count value at the settled interval. Its performance on high radiation, temperature, reproducibility, reparability of gamma and neutron, powers was investigated and verified the data using Mini-MCA. It shows that it has high potential to be used for spent fuel verification in the view point of safeguard monitoring for verifying spent fuel at CANDU reactor.