Most magnetic confinement fusion reactors (tokamaks, stellarators) make use of high power radio frequency (RF) actuators for access to and control of the burning plasma. SPARC, for example, will use 20+ MW of RF power in the ion cyclotron range of frequencies (ICRF) at 120 MHz to heat the plasma up to temperatures where fusion reactions become the dominant heating source. The RF antennas must be located close to the edge plasma with a direct line-of-sight for efficient coupling of the waves, therefore effectively functioning as plasma facing components (PFCs). The heat loads on the plasma facing surfaces of the antenna are typically cooled with forced liquid or gas flow through cooling channels beneath the surface. Forced flow cooling introduces additional points of failure in an already complicated system, and decreases efficiency through pumping losses. Existing long-pulse fusion reactors typically use high pressure water as a coolant, however water cooling inside the vacuum vessel introduces significant detritiation complexity and safety risks in a DT reactor environment. Tritium can be more easily separated from gaseous helium coolant, however gas cooling is much less effective as compared to liquid cooling.
This project will assess the suitability of heat pipes for cooling RF antennas and other in vessel components using multiphysics simulations of the heat pipe system coupling together heat transfer, turbulent vapor flow, and magnetohydrodynamic flow of liquid metals in a capillary.
This work is supported by an MITei seed grant funded by ENI.
