Our previous study indicated that infrared radiometry was suitable for nondestructive testing of joints in divertor structures for a fusion reactor. Radiation temperature difference between an unbrazed tile and a brazed one was clearly observed when the model divertor was heated using a halogen lamp. This paper describes the influence of three different heating methods on thermal images of model divertor that contain improperly bonded are as in the joint, in order to obtain information about the most appropriate heating method. Model divertors, which consist of carbon-carbon(C/C) composite tiles brazed to a Cu heat sink with different brazed areas, were heated using the halogen lamp, high temperature gas, or warm water. It was confirmed that the temperature difference between brazed and unbrazed areas could be detected by infrared radiometry and that the smallest unbrazed area was detected when warm water was used.
