Swelling Mechanisms of UO2 Lattices with Defect Ingrowths

The swelling that occurs in uranium dioxide as a result of radiation-induced defect ingrowth is not fully understood. Experimental and theoretical groups have attempted to explain this phenomenon with various complex theories. In this study, experimental lattice expansion and lattice super saturatio...

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Bibliographic Details
Published in:PloS one 2015-08, Vol.10 (8), p.e0134500-e0134500
Main Author: Günay, Seçkin D
Format: Article
Language:English
Subjects:
Algorithms
Alpha particles
Alpha rays
Atoms & subatomic particles
Cages
Dependence
Fission
Frenkel defects
Gamma rays
Irradiation
Kinetics
Lattices
Models, Chemical
Molecular chains
Molecular dynamics
Molecular Dynamics Simulation
Oxygen
Oxygen - chemistry
Oxygen ions
Radiation
Radiation effects
Simulation
Single crystals
Swelling
Uranium
Uranium - chemistry
Uranium Compounds - chemistry
Uranium dioxide
α Radiation
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Summary:The swelling that occurs in uranium dioxide as a result of radiation-induced defect ingrowth is not fully understood. Experimental and theoretical groups have attempted to explain this phenomenon with various complex theories. In this study, experimental lattice expansion and lattice super saturation were accurately reproduced using a molecular dynamics simulation method. Based on their resemblance to experimental data, the simulation results presented here show that fission induces only oxygen Frenkel pairs while alpha particle irradiation results in both oxygen and uranium Frenkel pair defects. Moreover, in this work, defects are divided into two sub-groups, obstruction type defects and distortion type defects. It is shown that obstruction type Frenkel pairs are responsible for both fission- and alpha-particle-induced lattice swelling. Relative lattice expansion was found to vary linearly with the number of obstruction type uranium Frenkel defects. Additionally, at high concentrations, some of the obstruction type uranium Frenkel pairs formed diatomic and triatomic structures with oxygen ions in their octahedral cages, increasing the slope of the linear dependence.
ISSN:1932-6203
1932-6203
DOI:10.1371/journal.pone.0134500