An improved interatomic potential for xenon in UO2: a combined density functional theory/genetic algorithm approach.

Area of Science:

• Materials Science
• Computational Materials Science
• Nuclear Materials

Background:

• Accurate modeling of xenon behavior in uranium dioxide (UO2) is crucial for nuclear fuel performance.
• Existing interatomic potentials for xenon in UO2 often fail to accurately predict defect energetics.

Purpose of the Study:

• To develop and validate an improved xenon interatomic potential for UO2.
• To assess the accuracy of existing xenon potentials against advanced computational methods.

Main Methods:

• Fitted a new xenon interatomic potential using iterative potential refinement (IPR), a genetic algorithm approach.
• Utilized density functional theory with the Hubbard U correction (DFT + U) for fitting and validation.
• Compared IPR-fitted potential energetics with DFT + U calculations for various xenon defect sites.

Main Results:

• The newly developed IPR-fitted xenon potential accurately predicts defect energetics across various incorporation sites.
• Previous xenon potentials overestimated defect formation energies and failed to rank small incorporation site defects correctly.
• The IPR potential shows good agreement with DFT + U calculations for interstitial and double Schottky defect clusters.

Conclusions:

• The IPR-generated xenon potential offers a significant improvement over existing models for UO2.
• The iterative potential refinement (IPR) method is a flexible and powerful tool for developing interatomic potentials.
• This work provides a more reliable computational tool for studying xenon behavior in nuclear materials.