Strain life analysis of the first wall mock up under ITER-relevant heat flux conditions

Abstract

Abstract The ITER first wall (FW) panels consist of plasma facing Be tiles, the CuCrZr alloy heat sink, and the stainless steel structural material. A copper layer of 1−2 mm is used between the Be tile and the CuCrZr for stress compensation. The results of cyclic high heat flux (HHF) tests employing an electron beam facility indicate that the failure/weak spot usually occurs at the joint corners between the Be tile and the copper layer. 3-D FEM (finite element method) thermo-mechanical analysis utilizing ANSYS software has been conducted to simulate the performance of a FW mock up (MU) under cyclic HHF test. The elastoplastic analysis results indicate that the copper layer is most sensitive to plastic deformation, and eventually the most risky location for failures. With the ANSYS strain-life fatigue module, based on the strain-life relation of copper from the ITER handbook, the fatigue life of the MU was predicted via FEM simulation. The results show that, when loaded with 2 MW/m², the small scale MU and the semi-prototype MU have a predicted life time of 12,220 cycles and 10,834 cycles, respectively. Although the shortest life time is located at the upper surface of copper which is joined to the Be tile, the major part of the copper has a life time of the same scale, which lies in the range of 10000–30000 cycles. When loaded with 2.5 MW/m², the life times of the MUs are 7432 cycles and 7343 cycles, respectively.