Thermal aspects of the CIT divertor and first wall

This paper summarizes the results of thermal analyses performed in support of the first wall (FW) and divertor design for the Compact Ignition Tokamak (CIT). The following issues are addressed: shaping of the inboard limiter and heat deposition on the limiter, global and local thermal peaking on the limiter tiles, and radiative cooling of the tiles and its impact on the vacuum vessel (VV) wall. It is shown that a simple cylindrical (or conical) inboard limiter is the most practical design for the CIT application and meets the design requirements. A methodology for analyzing global and local peaking factors is presented. It is shown that these factors are important in selecting allowable nominal heat loads and must be considered when developing candidate tile, first wall and vacuum vessel designs. Finally, the feasibility of radiative tile cooling is demonstrated