Structural and fracture mechanics analysis of ITER vacuum vessel

The eddy current is induced on ITER vacuum vessel (VV) by plasma centered disruption (CD). The electromagnetic (EM) force is loaded on VV by an interaction of the eddy current and magnetic field. Since it is difficult to perform in-service inspection due to inaccessibility of VV, it is important to estimate the allowable initial defect from the view point of fracture mechanics in order to assure the structural integrity of VV. The purpose of this study is evaluation of acceptable initial crack size of VV by a linear elastic fracture mechanics (LEFM). The fatigue crack growth is evaluated using the cracks modeled by the local three-dimensional (3D) finite element model to calculate a stress intensity factor as a function of crack size. As the results of these analyses, no significant unstable fracture and penetrating VV shell are foreseen by the CD.