R&D on high temperature components

Experimental studies were carried out to confirm the structural integrity of the key high temperature components, which are necessary to commercialize the HTGR, that is, an intermediate heat exchanger (IHX) and a coaxial hot gas duct. As for the IHX, the following tests were conducted: (1) creep collapse of tube against external pressure, (2) creep fatigue of tube against thermal stress, (3) seismic behavior of tube bundles, (4) thermal hydraulic behavior of tube bundles and (5) in-service inspection technology of tube with full-scale models. As for the coaxial hot gas duct, the thermal insulation performance as well as the structural integrity was investigated with the HENDEL-loop.