A B S T R A C T In order to simulate hydrogen charging and discharging cycles of mechanically loaded structures full 3D Macroscopic Rate Equation (MRE) modelling is proposed based on a finite element method (FEM). The model, implemented in the 3DS Abaqus software, uses a generalized transport equation, which accounts for mechanical fields, hydrogen transport and trapping, and their evolution with time. The influence of a-priori known thermal field has also been included. To ensure the solution

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... onvergence and the numerical stability, the trapping kinetic is introduced by using an approximation of the analytical solution the McNabb and Foster equation. Comparisons with a relevant 1D MRE code and with thermal programmed desorption (TPD) experimental results are performed on a 1D configuration to validate the model. Next, the model is used to simulate the tritium diffusion and trapping in a 2D geometry of interest in the upper plug of ITER tokamak, and results of tritium inventory are compared with an equivalent 1D calculation.