Impact of small defects and dislocation loops on phonon scattering and thermal transport in ThO2

Miaomiao Jin, Cody A. Dennett, David H. Hurley, Marat Khafizov

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Radiation damage can significantly degrade the thermal conductivity of ThO2 due to enhanced phonon-defect scattering. To quantify the effect of radiation-induced defects on thermal transport, we employ non-equilibrium molecular dynamics simulations to estimate the thermal conductivity in the presence of various types of defects. For each defect species, the phonon-defect scattering cross-section is extracted based on analytical models. In addition, the impact from two types of experimentally-observed dislocation loops (perfect and faulted) on thermal transport is examined with respect to the loop size and orientation. Notably, simulation cell size effects are analytically and quantitatively addressed via a phonon-mean-free-path-resolved analysis. It can be concluded that, for a given total number of defect sites per unit volume, agglomerating defects into larger clusters improves thermal conductivity compared to isolated defects. Importantly, this work provides quantitative information towards the defect-specific thermal conductivity, and phonon-defect scattering cross-sections, which can serve as inputs to large-scale transport models to quantify the evolution of overall thermal conductivity of ThO2 under irradiation.

Original languageEnglish (US)
Article number153758
JournalJournal of Nuclear Materials
Volume566
DOIs
StatePublished - Aug 1 2022

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • General Materials Science
  • Nuclear Energy and Engineering

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