Helium loop and test of the hot gas duct of HTR-10

A horizontal coaxial double tube hot gas duct (HGD) with an internal thermal insulation is to be used for the 10 MW High Temperature Reactor Test Module (HTR-10). Its thermal performance test was conducted on a helium test loop (HETL). The author deals with the technical feature of the HETL, the test section and the thermal performance of the HGD. The HETL consists of loop, purification, storage, pressure regulation system of helium gas, sampling and analyzing system of trace impurity in helium gas, etc.. The HGD test section with a triple tube structure includes an inner heater, a HGD model and a cold-hot gas mixer. A counterflow of cold and hot helium gas with respective temperature of 250 and 700 degree C was formed outside and inside the HGD model. The effective thermal conductivity (λeff) of the internal insulation of the HGD was investigated experimentally. The obtained relationship of λeff depending on temperature and pressure of helium gas are rational