Finite element analysis on the first wall electron beam welding of test blanket module

•First, The maximum equivalent stress of the first welding process is 563.7 MPa, and the second welding process is 821.7 MPa. Because of the reduction of equivalent stress with time, the maximum stress is concentrated on the final weld.•Overall, the second welding process is better than the first welding process. For the welding deformation in X and Z direction, the constraint is added at the corresponding maximum deformation in the actual FW welding. For the welding deformation in Y direction, can leave enough shrinkage allowance in advance when machining the outer parts.•Third, the finite element simulation of the FW electron beam welding has reference significance for the actual welding process and clamping conditions in the future. Test blanket module (TBM) uses the welding technology in its development process due to a component of the fusion test reactor. Electron beam welding (EBW) is selected as the welding of the TBM’s structure. As a part of the TBM, in the EBW process of the first wall (FW), there are a variety of welding processes for its selection. Here, geometry, thermal cycles, and the deformation characteristics of the FW under the two welding processes are simulated and analyzed by the finite element model. The results show that the equivalent stress of the second welding process is greater than that of the first welding process. For welding deformation, the first welding process is larger than the second welding process in the X and Z directions, but its position is different. In the Y direction, the welding deformation of the two welding processes is similar.