An estimate for thermal diffusivity in highly irradiated tungsten using Molecular Dynamics simulation

TL;DR

This paper introduces a simple model for estimating thermal diffusivity in highly irradiated tungsten using Molecular Dynamics simulations, effectively matching experimental data across various irradiation doses.

Contribution

The study presents a novel, straightforward model that predicts thermal diffusivity in irradiated tungsten from atomistic simulations, bridging the gap between perfect crystal conductivity and defect resistivity.

Findings

Model accurately predicts thermal diffusivity across irradiation doses.

Simulations closely match experimental measurements.

Effective for high-dose irradiation conditions.

Abstract

The changing thermal conductivity of an irradiated material is among the principal design considerations for any nuclear reactor, but at present few models are capable of predicting these changes starting from an arbitrary atomistic model. Here we present a simple model for computing the thermal diffusivity of tungsten, based on the conductivity of the perfect crystal and resistivity per Frenkel pair, and dividing a simulation into perfect and athermal regions statistically. This is applied to highly irradiated microstructures simulated with Molecular Dynamics. A comparison to experiment shows that simulations closely track observed thermal diffusivity over a range of doses from the dilute limit of a few Frenkel pairs to the high dose saturation limit at 3 displacements per atom (dpa).