Suppression of deuterium-induced blistering in pre-damaged tungsten exposed to short-duration deuterium plasma

Effects of pre-damage by 500 keV argon ion implantation on deuterium-induced blistering in tungsten has been investigated. After low-energy (40 eV) and high-flux (similar to 10(24) D/m(2)s) deuterium plasma exposure with short exposure duration (100 s), a large increase of deuterium retention is found in the predamaged tungsten, while surface blistering is significantly suppressed as compared to the undamaged one. According to elastic recoil detection analysis, a local deuterium concentration peak is observed at a depth of similar to 100 nm for the un-damaged tungsten, which is supposed to be related to the surface blistering with nanometer size. Comparison of deuterium retention in the near surface (within 300 nm) and in the bulk suggests that deuterium inward diffusion is more significant in the pre-damaged tungsten. It is speculated that the creation of deuterium trap-sites and enhancement of deuterium inward diffusion give rise to an increase of critical deuterium concentration for blistering and contribute to the suppressed deuterium-induced blistering on pre-damaged tungsten under the present exposure conditions. (C) 2018 Elsevier B.V. All rights reserved.