Modeling hydrogen isotope behavior in fusion plasma-facing components

In this work, we focus on understanding hydrogen isotope retention in plasma-facing materials in fusion devices. Two models are established to study this topic. One model simulates the hydrogen isotopes behavior in wall, and the other focuses on the relation between surface roughness and sputtering yield when material is bombarded by ion. Properties of hydrogen retention in metal are introduced in chapter 2. Both previous experiment and simulation work in this field are reviewed and summarized. A system of partial differential equations describing deuterium behavior in tungsten under various conditions is solved numerically and compared to other methods. The developed theory of hydrogen retention in metals includes classic, intercrystalline, and trapped-induced Gorsky effects. The results of the hydrogen isotopes model are listed in chapters 4 to 6. The bombardment and depth profile of 200 eV deuterium in single crystal tungsten and 1500 eV deuterium in polycrystalline tungsten are simulated and compared with other work. The total deuterium retention at various temperatures and fluences are also calculated and compared with available data. The results are in good agreement with previous research and therefore this model can be used to estimate deuterium inventory and recovery in future fusion reactors as described in chapter 6. Part of this model has been published in Journal of Nuclear Materials 446, 1-3, 56-62 (2014). Chapter 3 explains the model of sputtering yield and surface roughness, and the results are shown in chapter 7. This work have been published in Nuclear Instruments & Methods in Physics Research Section B-Beam Interactions with Materials and Atoms 281, 15-20 (2012) and Nuclear Instruments & Methods in Physics Research Section B-Beam Interactions with Materials and Atoms 323, 82-86 (2014)