Mixing of tungsten and carbon and tritium dynamics at fusion first wall

在聚变反应堆中，钨材料被认为用作等离子体面对材料，并且被认为将形成碳化钨。因此，揭示氚的行为变化是核聚变安全研究的重要课题。本研究在不同条件下对钨进行了C^+、He^+和D_2^+离子注入，并对氘的滞留行为进行了研究。结果表明，碳离子注入形成了辐照缺陷，碳在钨中的滞留改变了氘的滞留行为。此外，还发现氦离子辐照和氘滞留所形成的辐照缺陷也有所增加。对于C^+、He^+和D_2^+三重离子注入钨，氘主要被俘获在氦离子注入形成的辐照缺陷上。此外，与双离子（C^+和D_2^+）情况相比，钨表面的碳-碳键减少。结果表明，氦离子注入是溅射碳的一种方法，氦的滞留会影响氢同位素向体相的扩散。

In the fusion reactor, tungsten materials are considered to use as the plasma facing materials and it is thought that tungsten carbide will be formed. Therefore, it is important issue for fusion safety to reveal the tritium behavior changes. In this study, carbon ion (C^+), helium ion (He^+) and deuterium ion (D_2^+) were implanted into tungsten on various conditions, and the retention behavior of deuterium was clarified. As a result, it was shown that irradiation defects ware formed by carbon ion implantation and the deuterium retention behavior was changed by carbon retained in tungsten. In addition, it was suggested that the irradiation defects also formed by helium ion irradiation and deuterium retention increased. For the triple ions (C^+, He^+ and D_2^+) implantation into tungsten, it was shown that the deuterium was mainly trapped on irradiation defects formed by helium ion implantation. Moreover, the carbon-carbon bond on tungsten surface was decreased compared to that in the dual ion (C^+ and D_2^+) case. It was suggested that carbon was sputtered by helium ion implantation and the helium retention would have an influence on diffusion of hydrogen isotopes to bulk..