Development of High-Reliable Tungsten-Rhenium Alloy Thermocouple for Measuring in-Core Helium-Gas Temperature in Very High Temperature Gas-Cooled Reactor

Composite-type stranded tungsten-rhenium alloy thermocouples have been developed for measuring in-core outlet-gas temperature of 950 °C to 1200 °C in VHTR. Long-term high-temperature out-pile and in-pile tests for these thermocouples and postirradiation examinations were made. The results showed their reliable and stable performances at temperatures of 1000 °C and 1400 °C.