Vertical Displacement Events (VDE's) of plasma are one of the major concern in the design of the tokamak components inside the vacuum vessel, and in particular the divertor, because of the sideways forces generated by the interaction of the electric currents arising during VDE on the conductive metallic structures and the magnetic fields. The generation of these current is still matter of investigation either by theoretical studies and experimental campaign on the existing facilities, but it's still lacking a generally agreed methodology to define the design inputs for the in vessel components. Further, the codes simulating plasma wall interactions make an accurate reconstruction of the plasma dynamics but suffer of a little detail in the modeling of the mechanical structures, making so the obtained results not completely reliable to define the real loads. On the other hand, the use of phenomenological correlations relating the currents to the plasma nominal parameters before the VDE lead to a wide range of possible load values, with consequent uncertainties in the design process. In this work a different approach is used in the attempt to reduce this range, modeling the mechanical structures inside the vessel with a detail and a spatial resolution suitable to verify the design, and simulating the plasma actions only as current sources via inductive coupling and direct contact, disregarding the analysis of the plasma physical quantities evolution. In this way is possible also to follow the time transient behavior related to the current diffusion in the component under study without particular assumptions on the plasma wall interactions dynamics. So in this work, after a more detailed description of the model, the results obtained for the preliminary design of the divertor cassette for DEMO are given.
All Science Journal Classification (ASJC) codes
- Civil and Structural Engineering
- Nuclear Energy and Engineering
- Materials Science(all)
- Mechanical Engineering