2025 AIChE Annual Meeting

(497e) Cluster Dynamics Simulation of Sub-Surface Gas Dynamics in Plasma-Facing Tungsten

Authors

Dwaipayan Dasgupta - Presenter, University of Tennessee Knoxville
Holly Green, University of Tennessee Knoxville
Michael D. Ashburn, University of Tennessee, Knoxville
Sophie Blondel, University of Tennessee
Asanka Weerasinghe, University of Massachusetts, Amherst
Dimitrios Maroudas, University of Massachusetts
Brian D. Wirth, University of Tennessee, Knoxville
We present a systematic study of subsurface helium bubble dynamics based on a continuum-scale, spatially-distributed drift-diffusion-reaction cluster-dynamics model to simulate the evolution of helium clusters and bubbles, as well as helium retention, in low-energy helium plasma-exposed tungsten used as a plasma-facing component (PFC) in fusion reactors. Our cluster-dynamics simulator, Xolotl, has been validated against large-scale molecular-dynamics (MD) simulations and experimental data from the literature. To accurately predict the subsurface helium concentration, which reaches a steady state early during helium-plasma exposure, we have incorporated a simplified helium bubble bursting model into Xolotl to account for gas release when bubbles approach the tungsten surface. We will present a systematic comparison between model predictions and experimental measurements and discuss strategies to further improve the subsurface helium dynamics model implemented in Xolotl. Special emphasis will be placed on Xolotl predictions of helium retention in tungsten at different temperatures, as experimentally measured using thermal desorption spectroscopy.