Thermo-structural analysis of backwall in IFMIF lithium target, 2
Chida, Teruo; Ida, Mizuho; Nakamura, Hiroo; Sato, Toru*; Sugimoto, Masayoshi
This report describes results of thermo-structural analysis of a backwall in international fusion material irradiation facilities (IFMIF) lithium target preformed during FY2007. The IFMIF is an accelerator-based intense neutron source for testing candidate materials for fusion reactors. 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. Since previous model included only the backwall, a model including a part of target assembly is applied. In this analysis, three models were calculated. First model is a basic geometry adding a part of the target assembly to the backwall. Second model is a modified geometry which has a thin backwall. In a third model, a lip seal with a stress mitigation structure was applied to the second model. Calculation results showed that, in the third model, a thermal stress at a center of the backwall was 146 MPa below a permissible stress of F82H (455MPa: an yield strength at 300C) and maximum stress was 286 MPa below a permissible stress of SUS316L (328MPa: 3Sm value at 300C). These results showed a prospect of the present backwall configuration.