Tokamak 3D Heat Load Investigations using an Integrated Simulation Framework

Reactor class nuclear fusion tokamaks will be inherently complex. Thousands of interconnected systems that span orders of magnitude in physical scale must operate cohesively for the machine to function. Because these reactor class tokamaks are all in an early design stage, it is difficult to quantify exactly how each subsystem will act within the context of the greater systems. Therefore, to predict the engineering parameters necessary to design the machine, simulation frameworks that can model individual systems as well as the interfaced systems are necessary. This dissertation outlines a novel framework developed to couple otherwise disparate computational domains together into a single integrated package for the goal of high fidelity 3D heat load predictions. The framework, called the Heat flux Engineering Analysis Toolkit (HEAT), bridges the gap between plasma physics, engineering, visualization, high performance computing, and more. It is open source and has been used for time varying 3D heat load predictions on 5 tokamaks. The incredible heat loads that will be present in reactor class tokamaks can easily melt the plasma facing components (PFCs) if not properly managed, which can limit performance or even damage the machine. Because these PFCs provide the interface between dozens of reactor systems and the plasma, are expected to operate extremely close to their material limits, employ complicated 3D geometry to survive the hostile conditions inside a tokamak, and can be optimized via engineering design, they are the perfect investigative candidate for an integrated modeling framework such as HEAT. After providing contextual physics and background information, the HEAT architecture will be outlined in detail. An overview of the major investigations to date will be provided, including optical and gyro orbit heat loads on several tokamaks. The novel results that can only be obtained through an integrated simulation framework will be emphasized throughout.