Establishing the temperature and orientation dependence of the threshold displacement energy in ThO2 via molecular dynamics simulations
ThO2 is a promising fuel for next-generation nuclear reactors. As a critical quantity measuring its radiation tolerance, the dependence of the threshold displacement energy on temperature and crystal orientation in ThO2 is unclear and established using comprehensive molecular dynamics simulations in...
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Elsevier
2024-12-01
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| Series: | Nuclear Materials and Energy |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2352179124001972 |
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| author | Lin-Chieh Yu Shuxiang Zhou Miaomiao Jin Marat Khafizov David Hurley Yongfeng Zhang |
| author_facet | Lin-Chieh Yu Shuxiang Zhou Miaomiao Jin Marat Khafizov David Hurley Yongfeng Zhang |
| author_sort | Lin-Chieh Yu |
| collection | DOAJ |
| description | ThO2 is a promising fuel for next-generation nuclear reactors. As a critical quantity measuring its radiation tolerance, the dependence of the threshold displacement energy on temperature and crystal orientation in ThO2 is unclear and established using comprehensive molecular dynamics simulations in this work. For both Th and O primary knock-on atoms (PKAs), the thresholds, denoted as EdTh and EdO, respectively, are calculated using two different interatomic potentials. Similar temperature and orientation dependence are observed, albeit with some quantitative differences. While on average over all orientations, higher energy is required for Th PKAs than O PKAs to displace atoms, the polar-averaged EdTh is significantly lower than that for EdO. Further, EdTh and EdO show different crystal orientation dependence and temperature dependence. Notably, the cubic symmetry in the fluorite structure is followed by EdTh, but does not hold for EdO because of the existence of two sublattices. The much higher average EdO than EdTh and their different temperature dependence are interpreted by the distinct recombination rates of Th and O Frenkel pairs in thermal spikes, resulting from the substantially lower migration barriers of O vacancies and interstitials. The recombination of O vacancies and interstitials, both of which are charged, is further enhanced by the Coulomb interaction at small Frenkel pair separations. The new findings are discussed for their generality in fluorite-structured oxides by comparing the results in ThO2 and UO2. |
| format | Article |
| id | doaj-art-096b42e221a045e68bd4d5a8b0779253 |
| institution | Kabale University |
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| language | English |
| publishDate | 2024-12-01 |
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| series | Nuclear Materials and Energy |
| spelling | doaj-art-096b42e221a045e68bd4d5a8b07792532024-12-21T04:28:22ZengElsevierNuclear Materials and Energy2352-17912024-12-0141101774Establishing the temperature and orientation dependence of the threshold displacement energy in ThO2 via molecular dynamics simulationsLin-Chieh Yu0Shuxiang Zhou1Miaomiao Jin2Marat Khafizov3David Hurley4Yongfeng Zhang5Department of Material Science and Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA; Department of Nuclear Engineering and Engineering Physics, University of Wisconsin-Madison, Madison, WI 53706, USAIdaho National Laboratory, Idaho Falls, ID 83415, USADepartment of Nuclear Engineering, The Pennsylvania State University, University Park, PA 16802, USADepartment of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH 43210, USAIdaho National Laboratory, Idaho Falls, ID 83415, USADepartment of Nuclear Engineering and Engineering Physics, University of Wisconsin-Madison, Madison, WI 53706, USA; Corresponding author.ThO2 is a promising fuel for next-generation nuclear reactors. As a critical quantity measuring its radiation tolerance, the dependence of the threshold displacement energy on temperature and crystal orientation in ThO2 is unclear and established using comprehensive molecular dynamics simulations in this work. For both Th and O primary knock-on atoms (PKAs), the thresholds, denoted as EdTh and EdO, respectively, are calculated using two different interatomic potentials. Similar temperature and orientation dependence are observed, albeit with some quantitative differences. While on average over all orientations, higher energy is required for Th PKAs than O PKAs to displace atoms, the polar-averaged EdTh is significantly lower than that for EdO. Further, EdTh and EdO show different crystal orientation dependence and temperature dependence. Notably, the cubic symmetry in the fluorite structure is followed by EdTh, but does not hold for EdO because of the existence of two sublattices. The much higher average EdO than EdTh and their different temperature dependence are interpreted by the distinct recombination rates of Th and O Frenkel pairs in thermal spikes, resulting from the substantially lower migration barriers of O vacancies and interstitials. The recombination of O vacancies and interstitials, both of which are charged, is further enhanced by the Coulomb interaction at small Frenkel pair separations. The new findings are discussed for their generality in fluorite-structured oxides by comparing the results in ThO2 and UO2.http://www.sciencedirect.com/science/article/pii/S2352179124001972ThO2Threshold displacement energyMolecular dynamicsTemperature dependenceOrientation dependenceCoulomb interaction |
| spellingShingle | Lin-Chieh Yu Shuxiang Zhou Miaomiao Jin Marat Khafizov David Hurley Yongfeng Zhang Establishing the temperature and orientation dependence of the threshold displacement energy in ThO2 via molecular dynamics simulations Nuclear Materials and Energy ThO2 Threshold displacement energy Molecular dynamics Temperature dependence Orientation dependence Coulomb interaction |
| title | Establishing the temperature and orientation dependence of the threshold displacement energy in ThO2 via molecular dynamics simulations |
| title_full | Establishing the temperature and orientation dependence of the threshold displacement energy in ThO2 via molecular dynamics simulations |
| title_fullStr | Establishing the temperature and orientation dependence of the threshold displacement energy in ThO2 via molecular dynamics simulations |
| title_full_unstemmed | Establishing the temperature and orientation dependence of the threshold displacement energy in ThO2 via molecular dynamics simulations |
| title_short | Establishing the temperature and orientation dependence of the threshold displacement energy in ThO2 via molecular dynamics simulations |
| title_sort | establishing the temperature and orientation dependence of the threshold displacement energy in tho2 via molecular dynamics simulations |
| topic | ThO2 Threshold displacement energy Molecular dynamics Temperature dependence Orientation dependence Coulomb interaction |
| url | http://www.sciencedirect.com/science/article/pii/S2352179124001972 |
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