Nuclear fuel is packed in tubes welded to each end. For Generation IV reactors, cladding materials studied are ferritic-martensitic steels strengthened by a distribution of nanoscale oxides, which can increase the performance of the material, so the reactor.

The process of resistance butt welding is the reference method for welding the joints. The welding process is optimized to preserve the special properties of the material after welding.

The thesis proposed is to establish the relationship between the microstructures of specific inherited resistance welding zones and mechanical properties at room temperature and temperature of service for these assemblies. This thesis consists of the following main areas of work : optimization of the mechanical properties of the weld(the metallurgical optimization has already been carried out in a first thesis), the identification of cycles of deformation localy met by the material and the development of specific tests in order to reproduce these zones, the reproduction of these particular areas and their characterization.