Phase Lag Infra-red Thermal Examination (PLITE); A New Non-destructive Test Process

The International Organization of ITER (International Thermonuclear Experimental Reactor) specifies a requirement of 3 mm in diameter for the largest permissible flaw in the joint of the beryllium (Be) armor tiles and the underlying heat sink made of a copper-chrome-zirconium (CuCrZr) alloy for the first wall (FW). We investigated the sensitivity of a new non-destructive process of detecting these flaws using a method in which we mapped the phase lag of the temperatures on the surface of a sample during thermal cycling with a sinusoidally varying water temperature. A method with hot-cold water test that we had pioneered during the 1990's for the development of a water-cooled mid-plane modular limiter for Tore Supra had worked well with the high conductivity armor made of pyrolytic graphite brazed to copper tubes. The paper describes the experimental system, test samples and some experimental results.