Investigation of the neutron irradiation effects on the SIC/SIC composites at high temperature
Résumé
SiC/SiC composites have aroused interest for fusion and fission nuclear applications due to their thermomechanical properties at high temperature and behavior under irradiation (low swelling, neutron transparency, …), essentially as core materials. In this aim, the CEA has been working on the manufacture and the development of tubular SiC/SiC composites cladding elements for more than a decade. During this period, an optimization of the mechanical properties and the mastering of the manufacturing process have been conducted. Third generation SiC fibers, Hi-Nicalon S and Tyranno SA3, and high-purity CVI pyrocarbon interphase and SiC matrix have been employed for their expected behavior under irradiation. However, the latter consequences have to be properly evaluated. Different types of materials have then been produced for several irradiations. Firstly, the manufacturing process and the materials characterization will be described as the irradiations conditions. The CROCUS irradiation was aimed to determine the mechanical behavior of SiC/SiC minicomposites and of various brazing fillers while the CEDRIC irradiation had as objective to follow their creep at high temperature (600 – 1000°C). The TIRAMISU purpose was to evaluate the effect of high-doses (> 100 dpa) at the Sodium Fast Reactor temperature (550°C). The aftermath of these irradiations on the materials dimensions (swelling) as well as on its structure (fibers, interphase) and mechanical properties will then be evaluated.