Hydrogen isotopes are retained in plasma-facing fusion materials, triggering hydrogen embrittlement and changing tritium inventory as a function of exposure to neutron irradiation. But modeling highly damaged materials—exposed to over 0.1 displacements per atom (dpa)—where saturation of damage is often observed, is difficult because a microstructure containing high density of defects evolves nonlinearly as a function of dose. In this study we show how to determine the defect and hydrogen isotope content in tungsten exposed to high irradiation dose, using no adjustable or fitting parameters. First, we generate converged high dose ($>1$ dpa) microstructures, using a combination of the creation-relaxation algorithm and collision cascade simulations. Then we make robust estimates of vacancy and void regions using a modified Wigner-Seitz decomposition. The resulting estimates of the void surface area enable predicting the deuterium retention capacity of tungsten as a function of radiation exposure. The predictions are compared to ${}^3\mathrm{He}$ nuclear reaction analysis measurements of tungsten samples, self-irradiated at 290 K to different damage doses and exposed to low-energy deuterium plasma at 370 K. The theory gives an excellent match to the experimental data, with both model and experiment showing that 1.5–2.0 at.% deuterium is retained in irradiated tungsten in the limit of high dose.

中文翻译：

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离子辐照钨中高剂量微观结构和氢保留的无参数定量模拟

氢同位素保留在面向等离子体的聚变材料中，触发氢脆并改变氚库存作为暴露于中子辐射的函数。但是，对高​​度受损的材料（每个原子的位移超过 0.1 次 (dpa)）进行建模是很困难的，因为包含高密度缺陷的微观结构会随着剂量的变化而非线性地演化，而在这种情况下，通常会观察到损坏的饱和状态。在这项研究中，我们展示了如何在不使用可调整或拟合参数的情况下确定暴露于高辐射剂量的钨中的缺陷和氢同位素含量。首先，我们生成收敛的高剂量（$>1$dpa) 微观结构，使用创建-松弛算法和碰撞级联模拟的组合。然后，我们使用修改后的 Wigner-Seitz 分解对空位和空位区域进行稳健估计。由此产生的空隙表面积估计值能够预测钨的氘保留能力作为辐射暴露的函数。预测比较${}^3\mathrm{他}$ 钨样品的核反应分析测量，在 290 K 下以不同的损伤剂量自辐照并在 370 K 下暴露于低能氘等离子体。 该理论与实验数据非常吻合，模型和实验均表明 1.5–在高剂量限度内，2.0 at.% 的氘保留在辐照钨中。