Abstract
Thermal transport in nuclear fuels used for nuclear energy applications is directly tied to performance and reliability. Uranium dioxide (UO2), one of the most important nuclear fuels, can accumulate excess oxygen atoms as interstitial defects, which significantly impacts thermal transport properties. In this study, thermal conductivities and inelastic neutron scattering (INS) measurements on UO2+x were performed at low temperatures (2-300 K). The thermal conductivity of UO2+x (x = 0, 0.03, 0.04, and 0.11) is significantly suppressed compared to UO2 except near the Néel temperature TN = 30.8 K, where it is independent of x. INS measurements demonstrate that the heat capacities and phonon group velocities of UO2 and UO2.08 are similar, and the suppressed thermal conductivity results from smaller phonon lifetimes. These perceptions advance our understanding of thermal transport properties in advanced nuclear fuels and guide safe and economic utilization of nuclear energy.
| Original language | English |
|---|---|
| Article number | 012202 |
| Journal | Applied Physics Letters |
| Volume | 121 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jul 4 2022 |
Funding
H.M., M.S.B., K.G., and M.E.M. were supported by the Center for Thermal Energy Transport under Irradiation, an Energy Frontier Research Center funded by the U.S. Department of Energy (DOE), Office of Science, United States, Office of Basic Energy Sciences. D.J.A. and K.G. acknowledge support from the Advanced Fuel Campaign program (INL). Portions of this research used resources at the Spallation Neutron Source, a U.S. DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. We are grateful to David A. Andersson and Christopher R. Stanek for providing UO2+x crystals for the thermal conductivity measurements. This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan).