DEUTERIUM AND HELIUM ION IRRADIATION OF NANOGRAINED TUNGSTEN AND TUNGSTEN-TITANIUM ALLOY MATERIALS

Abstract

Tungsten has long been considered a primary candidate for the plasma-facing components of nuclear reactors due to its favorable thermal and mechanical properties such as high melting temperature, low erosion yield, and low fuel retention. It will be used in the divertor region of the International Thermonuclear Experimental Reactor (ITER). However, irradiation with energetic particles makes tungsten susceptible to cracks, blisters, bubbles, and other morphological changes. This thesis aimed to investigate two new materials, nanograined tungsten and a nanograined tungsten-titanium alloy, for potential use as plasma-facing materials by analyzing their deuterium and helium retention and morphological changes after plasma exposure. It was found that after plasma irradiation, nanograined tungsten had smaller blisters, was less prone to fuzz formation, and retained less helium than common polycrystalline tungsten. Additionally, a nanograined tungsten-titanium alloy showed a lower concentration of blisters on its surface than pure tungsten. Further research involving bulk samples rather than thin films and a broader range of plasma irradiation conditions is needed in order to accurately assess the capabilities of nanograined tungsten and nanograined tungsten-titanium alloys as plasma-facing materials.