Thermal hydraulic analysis of the TPX plasma facing components

This paper describes the thermal hydraulic analysis performed for the plasma facing components (PFC) of the Tokamak Physics Experiment (TPX). The plasma facing material for TPX is graphite and cooling is provided by water. The type of cooling, the mounting method (i.e., bolting or brazing) and the structural material depends on the heat flux anticipated in different areas. Since TPX is a long-pulse machine, all analysis was done for steady-state conditions. To reduce the radiation enhanced sublimation, the armor temperature has to be less than a 1000°C toroidal average with a 1200°C local peak. In addition, there are temperature limits on structural materials and belleville washers. In order to reduce the impurity sources to the plasma, the minimum wall temperature has to be more than 150°C. TPX plasma facing components analyzed in this study were; inboard and outboard limiters, neutral beam armor, ripple plates and diverters. The heat flux on these components varies from 0.15 MW/m² for the passive plate armor to 15 MW/m² for the divertor tiles. From thermal hydraulic considerations, TPX plasma facing components can be divided into five types: (1) graphite armor bolted to water-cooled, corrugated titanium structured (for heat flux less than 1.0 MW/m²), (2) graphite armor bolted to water-cooled copper plates, (3) graphite armor brazed to water-cooled copper plates, (4) graphite monoblocks with DS-copper tubes, and (5) graphite Monoblocks with DS-copper tubes with swirl tube inserts (for heat flux >5 MW/m²)