Thermal gradient effect on hydrogen transport in tungsten
Year: 2025
Type: article
Abstract: One key challenge for efficiency and safety in fusion devices is the retention of tritium (T) in plasma-facing components. Tritium retention generates radioactive concerns and decreases the amount of fuel available to generate power. Hence, understanding the behavior of T in tungsten (W), as the main candidate as armor material, is critical to the deployment of fusion as a reliable energy source. In this work, we have studied the effect of a thermal gradient in the transport properties of hydrogen (as a T surrogate) in pure W. Strong thermal gradients develop in the divertor as a result of the intense energy fluxes arriving at the material. We have developed an analytical approach to compute the heat of transport ( Q ∗ ) that is parameterized from molecular dynamics (MD) simulations. Q ∗ is a parameter needed in irreversible thermodynamics frameworks to understand mass transport in the presence of thermal gradients. We show that Q ∗ can be written as a function of temperature, temperature gradient, a characteristic length and the ratio of the rates towards hot and cold regions. Furthermore, we describe how, to first order, the dependence of Q ∗ on the thermal gradient vanishes, in agreement with MD results. On average, we find Q ∗ = − 5.41 × 10 − 3 k T 2 eV for H in pure W, with k the Boltzmann constant and T the temperature.
Source: Nuclear Fusion
Institution: Clemson University
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,595
OpenAlex ID: W4416754064