Modeling of SiCf/SiC composite structures for nuclear components

The use of low activation Ceramic Matrix Composites (CMCs) appears as the most promising solution to obtain high safety standards in future fusion power reactors. Among them, silicon carbide composites (SiCf/SiC) are the primary composite materials being evaluated and developed world-wide for fusion structural applications. Although these composites are already widely used in the aerospace industry, they are relatively new materials for fusion applications, and a number of key issues remain still to be solved. Among them, specific design methodologies for fusion reactor structural components must be established. This involves the development and implementation in finite-element codes of material models capable to describe the complex non-linear mechanical behavior of those composites. Such a model has been implemented in the FEM code CASTEM 2000 used within the CEA. This paper describes the details of the model and identifies the major improvements for the analyses. Furthermore, if the potential advantages of SiCf/SiC composites over more common metallic materials have to be fully evaluated, appropriate resistance criteria must be assessed. Specific criteria for CMCs have then been identified and are discussed in the paper. Results obtained with these criteria are compared with those obtained with more classical ones. The example of application to the Tauro blanket is presented.