Development of in-pile instruments for fuel and material irradiation tests

Shibata, Akira ; Kitagishi, Shigeru  ; Kimura, Nobuaki ; Saito, Takashi; Nakamura, Jinichi ; Omi, Masao; Izumo, Hironobu; Tsuchiya, Kunihiko 

To get measurement data with high accuracy for fuel and material behavior studies in irradiation tests, two kinds of measuring equipments have been developed; these are the Electrochemical Corrosion Potential (ECP) sensor, the Linear Voltage Differential Transformer (LVDT) type gas pressure gauge. The ECP sensor has been developed to determine the corrosive potential under high temperature and high pressure water condition. The structure of the joining parts was optimized to avoid stress concentration. The LVDT type gas pressure gauge has been developed to measure gas pressure in a fuel element during neutron irradiation. To perform stable measurements with high accuracy under high temperature, high pressure and high dosed environment, the coil material of LVDT was changed to MI cable. As a result of this development, the LVDT type gas pressure gauge showed high accuracy at 1.8% of a full scale, and good stability.