Preliminary calculation of stress change of fuel pin using SiC/SiC composites for GFR with changing of thermal conductivity degradation by irradiation

Lee, J.-K.; Naganuma, Masayuki  

Gas cooled Fast Reactor (GFR) is being researched as a candidate concept of Generation IV international Forum. As a main feature of GFR, it should be maintained high temperature and pressure of coolant gas for heat transfer efficiency. Present study assumed a cladding tube of fuel pin type reactor, and using of SiC/SiC composites. Thermal stress of cladding wall was estimated with a condition of linear heat rate and temperature. Through the present work, the ways to improve an applicability of SiC/SiC were clarified; they are the densification of matrix and the improvement of interphase in terms of fabrication. From the viewpoint of core design, the degradation of thermal conductivity by irradiation was identified as the most important factor. These results should be helpful not only to determine the geometries of core component but also to indicate the improvement direction of SiC/SiC.