The THELMA Electromagnetic Model of the Poloidal Field Conductor Insert Joint

Abstract

The Poloidal Field Conductor Insert (PFCI) is a large NbTi single-layer coil, made of 10 turns of a full-size ITER type cable-in-conduit conductor. One peculiarity of this prototype is the presence of an intermediate "shaking-hands" joint between two coil sections. PFCI is going to be tested at the JAERI facility in Naka (Japan), with the aim to investigate both the cable and the intermediate joint performances. In order to predict the PFCI behavior, a set of analyses with the THELMA code is being carried out, in which separate components of PFCI, or the whole coil are modeled. To this purpose, the THELMA electromagnetic model of the joint, based on a lumped equivalent network, has been upgraded to take into account the new joint geometry and to allow the inductive effects in the joint to be considered. The paper presents in detail this model, showing its geometrical and electrical aspects. Different approaches to the joint inductive description are also presented and compared, together with the results of some simulation of the joint behavior.