Nonthermal Effects in H-doped Tungsten at High Electronic Temperatures
Nonthermal Effects in H-doped Tungsten at High Electronic Temperatures
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DOI：
10.1016/j.jnucmat.2022.153896
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发表时间：
2022-06
影响因子：
3.1
通讯作者：
P. Yu;B. Pan
中科院分区：
文献类型：
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作者：
P. Yu;B. Pan
在聚变反应堆中，高温等离子体强烈、连续地发射高能光子，照射第一壁的钨材料。高能光子的照射会在钨材料中引起非热事件。本文利用密度泛函理论研究了H掺杂钨金属在高电子激发态下的结构特征。研究发现，随着电子激发能的增加，体系不仅可以发生非热膨胀，而且在激发能达到阈值时，会自发地发生从体心立方（BCC）相到面心立方（FCC）或六方密排立方（HCP）相的相变。公开了与相变相关的激发能量阈值与钨中掺杂杂质的浓度之间的关系，该关系可以使用经验公式来表达。此外，还揭示了电子激发和杂质原子对相变的协同效应。我们的结果深入了解了高能光子对聚变反应堆第一壁钨的辐照效应。
In a fusion reactor, the plasma with very high temperature intensely and continuously emits high-energy photons, which irradiate the tungsten material of the first wall. The irradiation with high-energy photons causes nonthermal events in the tungsten material. In this paper, the structural features of H-doped tungsten metal at highly electronic excitation states are studied using density functional theory. It has been found that the system can not only undergo nonthermal expansion with increasing electronic excitation energy, but also a phase transition from body-centered cubic (BCC) phase to face-centered cubic (FCC) or hexagonal close-packed cubic (HCP) phase occurs spontaneously with a threshold value of excitation energy. The relationship between the excitation energy threshold associated with the phase transition and the concentration of doped impurity in tungsten is disclosed, which can be expressed using an empirical formula. In addition, the synergistic effect of electronic excitation and impurity atoms on the phase transition is revealed. Our results give a deep insight into the irradiation effect of the high-energy photons on the first-wall tungsten in a fusion reactor.