Influence of Lithium Vacancy Defects on Tritium Diffusion in β-Li2TiO3

Goswami, K.N. and Murphy, S.T. (2020) Influence of Lithium Vacancy Defects on Tritium Diffusion in β-Li2TiO3. Journal of Physical Chemistry C, 124 (23). pp. 12286-12294. ISSN 1932-7447

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Abstract

Lithium metatitanate, Li2TiO3, is a leading candidate for application as a tritium breeding material in a future fusion reactor. Following transmutation of lithium, the tritium must escape the crystal in order to be extracted for use in the fusion plasma. The rate-limiting step to release tritium from the Li2TiO3 pebbles is diffusion through the crystal grains. In this work, the activation barriers for tritium diffusion have been calculated using density functional theory. The results show that tritium can diffuse as an interstitial with a barrier of 0.52 eV. However, when a tritium ion becomes bound to a lithium vacancy defect, the energy required to either detrap the tritium from the vacancy or for the cluster to diffuse increases to >1 eV. Overall, these results suggest that the introduction of lithium vacancies due to Li burn-up may lead to an increase in tritium retention in the pebbles. Copyright © 2020 American Chemical Society.

Item Type:
Journal Article
Journal or Publication Title:
Journal of Physical Chemistry C
Additional Information:
This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in The Journal of Physical Chemistry C, copyright © American Chemical Society after peer review. To access the final edited and published work seehttps://pubs.acs.org/doi/10.1021/acs.jpcc.0c02551
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/2500/2504
Subjects:
ID Code:
147370
Deposited By:
Deposited On:
14 Sep 2020 15:50
Refereed?:
Yes
Published?:
Published
Last Modified:
25 Sep 2020 05:01