How to Remove Deuterium Isotopes from Tungsten-Based Materials?

Deuterium in tungsten-based materials can be removed by isotope replacement and thermal desorption. Tungsten-based material is a kind of tungsten-based alloy material composed of other elements, which has the characteristics of high melting point, high hardness, and high sputtering threshold, and is widely used in the field of nuclear fusion energy.

In nuclear fusion reactors, tungsten-based materials and deuterium play the roles of "protector" and "provider" respectively. As a fuel, deuterium itself does not participate in the fuel cycle of the fusion reaction, but it will penetrate and remain inside the tungsten-based material, degrading the material's performance, and it is necessary to prevent its retention and effectively remove it in a certain way.

Thermal Desorption

The thermal desorption method uses the principle of gradient concentration to destroy the internal dynamic balance of tungsten-based materials to remove the resident deuterium. Among them, the principle of gradient concentration means that due to the concentration difference of gas or liquid on both sides of the material interface, the high concentration tends to the low concentration until the equilibrium state. Under the action of concentration gradient, hydrogen isotopes at high temperature and high pressure enter the tungsten-based material through surface adsorption, dissolution, and diffusion, and finally reach dynamic equilibrium. The thermal desorption method adjusts the initial state of deuterium (high temperature and high pressure), so that the internal deuterium concentration is higher than the external deuterium concentration, and finally the vacuum pump is used to remove.

Isotope Replacement Method

Isotope replacement is also commonly used to remove deuterium resident in tungsten-based materials, using the same principle of isotopic chemistry. In the same hot-charging environment, the fuel chooses another isotope of hydrogen (protium) to replace the deuterium remaining in the tungsten-based material, to achieve the purpose of removing the deuterium retention.

At present, the isotope replacement method and thermal desorption method are considered the most feasible deuterium removal methods because they both meet the advantages of high deuterium removal efficiency and no damage to deuterium.

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