Various kinds of material testing are strongly needed for the evaluation of mechanical properties of materials irradiated in nuclear reactors and elsewhere. It is necessary to perform these tests in a limited space with concrete shielding, because of the radiation from activated materials. Therefore, it is required to develop remote handling technology with easy operation for the manipulator and miniaturized equipment.
A high cyclic fatigue testing machine was developed to evaluate the fatigue characteristics of LWR (light water reactor) fuel cladding using an arc-shaped specimen. This machine consists of a main body and specimen assembling gear (Fig. 10-1) which fixes a test piece. In the past, fatigue test data varied widely due to the inevitable applied force on installing arc-shaped specimens to the machine. New remote handling technology was developed by equipping the operable torque wrench with load cell equipped manipulators, and this made it always possible to fix a test specimen within the allowable alignment without distortion. The fatigue test data obtained as shown in Fig. 10-2 are almost equivalent to standard test results. By exchanging the specimen handling tool with remote handling, the machine is utilized for several mechanical tests such as a tensile test, a crack propagation test, a fracture toughness test and so on, as well as a fatigue test with an arc-shaped specimen as shown in Fig. 10-3. The mechanical tests using this technology will be quite useful for R&D works of LWR fuels and structural materials in the future. |