The research for packed Pebble-bed for Fluoride salt-cooled high temperature reactor, with its advantages of passive safety feature and higher thermal efficiency compared to conventional nuclear power plants, is developing actively by many research institutes. In this study, the authors introduce a new device which has non-invasive type measurements in order to figure out the statistical distribution of temperature and heat transfer performance of randomly packed spherical fuels. This device is made up with a metallic shell of 63.5mm diameter, and it contains a circuit board and battery to drive temperature measurements, wireless data transfer. The circuit board used for receive measured temperature from several K type thermocouples is based on the ATmega328 type Microprocessor (MCU). This board collects temperature at multiple points and send data to the receiver in a wireless way. The authors descript its communication protocol and driving method of the device. After that, the development process for configuring new concept wireless device was explained. In addition, heat generation from the inside of the spherical device was realized by using induction heating and fabric-based heating material. Preliminary results from the experiment on the wireless communication of multiple devices are presented. The statistical distribution of the local heat transfer coefficient for multiple packed-pebbles can be obtained by extending this preliminary experimental method.
