A kinetic surface model is presented and used to explain the loading and desorption kinetics of tritium retained in micrometre-sized tungsten (W) dust particles. The model describes the sticking of hydrogen isotopes from the gas phase to W surfaces and the desorption from W surfaces. The initial sticking coefficient is set to one and independent of the temperature. The activation energy for desorption depends on the hydrogen coverage of the surface and is parameterised with density functional theory (DFT) calculations for W(100), W(110) and W(111) surfaces. The DFT-parameterised model is successfully compared to experimental results showing that the amount of measured tritium as well as the desorption kinetic can be modelled with only tritium adsorbed on the surface of W dust particles. Then, the model is used to explore possible scenarios to remove the tritium from the W surfaces by exposing the tritiated surfaces to either deuterium and hydrogen. The simulations suggest that it can be possible to remove all the tritium trapped on the W surfaces even at room temperature as soon as the hydrogen or deuterium pressure is higher than the tritium pressure. This gives opportunity to build tritium removal scenarios for ITER.

提出并使用动力学表面模型来解释保留在微米级钨 (W) 尘埃颗粒中的氚的加载和解吸动力学。该模型描述了氢同位素从气相粘附到 W 表面以及从 W 表面解吸。初始粘附系数设置为 1 且与温度无关。解吸的活化能取决于表面的氢覆盖率，并通过 W(100)、W(110) 和 W(111) 表面的密度泛函理论 (DFT) 计算参数化。DFT 参数化模型成功地与实验结果进行了比较，实验结果表明测量的氚量以及解吸动力学可以仅用吸附在 W 尘埃颗粒表面上的氚进行建模。然后，该模型用于探索通过将氚化表面暴露于氘和氢来从 W 表面去除氚的可能方案。模拟表明，即使在室温下，只要氢或氘压力高于氚压力，就有可能去除所有被困在 W 表面上的氚。这提供了为 ITER 构建氚去除方案的机会。