由于聚变堆中等离子体边缘处的氮与第一壁钨（W）材料相互作用，导致部分W材料氮化成WN化合物。令人惊奇的是第一壁中的WN化合物内氢的同位素氘滞留量显著低于在纯钨中的滞留量，并随氮含量的增加氘的滞留量减少。本项目拟发展紧束缚分子动力学方法，详细研究在高能粒子辐照下第一壁中WN化合物的结构特征、力学性能、热输运性能、氘和氚的迁移和滞留行为，揭示其迁移和滞留行为与体系中氮含量、WN化合物微结构和特定晶格振动模的内在关联。同时研究WN化合物表面原子被溅射离开表面的物理过程。. 本项目的研究不仅要深入解释相关的实验现象，而且为评估第一壁中WN化合物对反应堆环境的耐受性提供参考。此外，为寻找出可显著改善WN材料综合性能的W与N浓度提供参考。

The interaction of the nitrogen at the plasma edge in the fusion reactor with the first wall W material causes parts of the W material to be nitrided, forming WN compounds. Surprisingly, the isotope deuterium retention of hydrogen isotope in the formed WN compounds in the first wall is significantly lower than that in the pure tungsten, and the retention of deuterium decreases with increasing N content. We in this proposal will develop a tight-binding molecular dynamics approach to study in detail the structural characteristics, mechanical properties, thermal transport properties, migration and retention behavior of D and T in the WN compounds under high-energy particle irradiation, revealing the relationship between the retention behavior and several factors such as the content of N in the system, the microstructure of WN compounds and the vibration mode. At the same time, the process of some atoms ejected from the surface of the WN compounds is systematically studied. . Based on the research of this project, we may not only gain deep understandings on the relevant experimental phenomena, but also evaluate the tolerance of the WN compounds to the extreme environment in the reactors. In addition, our research in this project might be valuable to synthesize the optimal properties of WN materials in experiment.