Conceptual design of a helium heater for high temperature applications

•A special design of heater with two vessels is introduced for the operation at 10 MPa and 800 °C.•The additional coupling between the cold leg and the hot leg of the loop due to the heater design has an impact on the loop energy budget.•Reducing the heat transfer between the two flow channels inside the heater by means of a helium gap in the inlet nozzle is proven to be effective.

The Karlsruhe Advanced Technologies Helium Loop (KATHELO) has been designed for testing divertor modules as well as qualifying materials for high heat flux, high temperature (up to 800 °C) and high pressure (10 MPa) applications. The test section inlet temperature level is controlled using a process electrical heater. To cope with the extreme operating conditions, a special design of this unit has been proposed. In this paper the conceptual design of the unit will be presented and the impact of the coupling between the cold and hot helium gas on the overall efficiency of the loop will be investigated. The detailed thermal-hydraulic analysis of the feed through of the hot helium into the low temperature pressure vessel using ANSYS CFX will be presented. The impact of the design choices on the overall energy budget of the loop will be analyzed using RELAP5-3D.