Valter Cocilovo

Modeling of Electromagnetic Loads on DEMO First Stage Divertor

Abstract In this work the analysis of the effects of the poloidal currents flowing on the cooling piping of the divertor armour tiles is carried out. To deal with the complexity of the problem a parametric solving scheme, starting from the nominal plasma current value, was adopted to contemplate the great variability of the possible cases deriving from the experimental data base and to compensate the lack of knowledge due to the not well assessed theory on the plasma wall interaction. Further to overcame the difficulties in modeling the real design of the piping with the necessary spatial resolution to individuate the local current concentration areas the methodology illustrated here is based on shell interfaces for solving either the electric and the mechanical problem. This approach proved to be capable to highlight the critical design areas and was useful to suggest the relative remedial corrections.

First Italian JT-60SA TF coil winding pack preliminary insertion into casing

In the framework of the Broader Approach Agreement between Europe and Japan for the construction of the JT-60SA tokamak in Naka, Japan, ENEA is committed to supply nine toroidal field (TF) superconducting magnets. The supply is carried out via a contract awarded in 2011 to ASG Superconductors, in which all the qualification activities have been accomplished and the manufacturing has already considered every step of fabrication. Six of the foreseen winding packs (WP) have been already wound, vacuum pressure impregnated and tested; the subsequent phase of the fabrication, consisting in the into casing insertion of the WP, has started. The critical processes have been qualified through the use of dedicated mock-ups. To carry out the insertion operation a dedicated tooling has been designed and installed in ASG. It consists of a central core on which the WP is grasped and of two lateral carriages for the casing component approaching in horizontal position. The present paper describes the WP manufacturing process highlighting some issues as the dimensional tolerances and the electrical insulation under vacuum. The final phase of fabrication, consisting in the into casing insertion of the WP, will be reported describing all the steps to arrive at the completion of the first TF coil.

Modeling of Long Term Effects on Plasma Facing Components for a Fusion Power Reactor

Abstract In a fusion power reactor the Plasma Facing Components (PFC) will experience a thermal and neutron irradiation induced creep together with tensile properties degradation and swelling due to neutron irradiation. So the investigation of the long term creep effects on the materials used for the PFC’s in a fusion power plant are of vital importance for the design and safe operation of the device. On the other hand the creep behavior study for a given material requires long and expensive test campaigns, repeated on specimens at different levels of neutron irradiation, because of the material parameters variation due to the cumulated irradiation. In this work we want to investigate if the numerical mechanical simulations employment, according to a proper methodology, could reduce the number of needed creep tests, because this would be a valuable help in defining suitable materials and valid conceptual designs for PFC’s. For this reason a method based on the systematic variation of the parameters of the empirical law, e.g. the Norton-Bailey, is outlined. To exemplify it, the behavior of a simplified model is analyzed under thermal and mechanical cyclic loading in a time transient elasto-plastic simulation, including the creep behavior, varying the parameters in the empirical creep law for the material.