Thermo-structural analysis of backwall in IFMIF lithium target

Nakamura, Hiroo; Ida, Mizuho; Shimizu, Katsusuke*; Sugimoto, Masayoshi

This report describes results of thermo-structural analysis of a backwall in IFMIF lithium target performed during FY 2003-2006. The IFMIF is an accelerator-based intense neutron source for testing candidate materials for fusion reactors. Intense neutrons are emitted inside the Li flow through a backwall. The backwall is made of 316L stainless steel or RAFM. Since the backwall is operating under a severe neutron irradiation of 50 dpa/year and a maximum nuclear heating rate of 25 W/cm, thermo-structural design is one of critical issues in a target design. Thermal stress was calculated using the ABAQUS code. In a case of the 316L stainless steel backwall, the maximum thermal stress was beyond the permissible stress. On the other hand, in a case of the F82H backwall, a maximum thermal stress was 289 MPa below the permissible stress (455 MPa). Therefore, F82H is recommended as the backwall material.