2D Thermal Analysis of the Superconducting Proposal for the TF Magnets of FAST

Abstract

The design of FAST (Fusion Advanced Studies Torus), the Italian proposal of a Satellite Facility to ITER, is currently under review in order to verify the feasibility of a superconducting version of its magnet system. In a previous study, the 1D analysis of the thermal-hydraulics of the TF cable in conduit conductors (CICCs) have been investigated with respect to one of the most critical operating scenarios (the H-mode reference scenario). In that case the heat coming from the casing to the winding pack due to the nuclear heat from the plasma has not been modeled, nonetheless, based on the experience on other superconducting tokamak machines, the necessity for a proper shield and case cooling system has been recognized. In the present paper the effect of the heat coming from the casing is quantified through a 2D analysis of the TF cross section. The contribution of the casing is further employed as an input for a successive 1D thermal-hydraulic analysis of the CICCs.

FAST: A European ITER satellite experiment in the view of DEMO

“…As the presence of a nuclear shield would considerably impact the machine geometry, a balance of pros and cons has driven us to consider, at least for this feasibility study, only a solution without any shield, but where the SS casing is actively He cooled by means of ad-hoc designed channels. With this design the conductor temperature margin, resulting from a corresponding NH value of about 5 mW/cm 3 , is T margin = 0.9 K. The main result of this feasibility analysis is that no major modifications are needed in the machine load assembly for the TFSC design, though a refinement of the used models is mandatory and that, probably, a small increase of the major radius (maintaining the same plasma volume) should be considered [14].…”

“…In order to eliminate any limitation of the plasma duration (i.e. NICD scenario) and to address the DEMO conditions, a feasibility study has been worked out to analyze the possibility of realizing FAST with a complete set of superconductor coil [13,14]. So far, the exercise has been performed only for the 7.5 T reference scenario.…”

1-D Electromagnetic and Thermal-Hydraulic Analysis of the Superconducting Proposal for the CS Magnets of FAST

“…It has been conceived as a compact ( 1.82 m) machine working at high field ( up to 8.5 T) and high plasma current ( up to 8 MA). Currently, FAST magnetic system is designed with 18 TF (Toroidal Field), 6 CS (Central Solenoid) and 6 PF (Poloidal Field) resistive coils, cooled by helium gas flow at 30 K. A feasibility study to verify whether a superconducting (SC) solution for the whole magnetic system would be possible or not, Manuscript avoiding any major modifications to the machine geometry or scenarios, has been discussed in [3], and with respect to the TF magnet system in [4] and [5]. This paper focuses on the proposed superconducting solution for the CS magnet in order to assess its feasibility, keeping the reference H-mode scenario, foreseen for the resistive configuration of the machine, as a constraint, and regardless the performance degradation of the conductor.…”