High-precision molecular dynamics simulation of UO2-PuO2: pair potentials comparison in UO2

TL;DR

This study evaluates ten pair potential models for simulating UO2, identifying the most accurate ones for high-temperature properties of uranium dioxide using high-precision molecular dynamics with GPU acceleration.

Contribution

It compares and assesses the accuracy of recent pair potentials for UO2 in high-temperature simulations, highlighting the best models for reproducing experimental data.

Findings

MOX-07 and Yakub-09 best reproduce experimental data

These potentials outperform older models above 2500K

High-precision GPU-based MD enables accurate property predictions

Abstract

Our series of articles is devoted to high-precision molecular dynamics simulation of mixed actinide-oxide (MOX) fuel in the approximation of rigid ions and pair interactions (RIPI) using high-performance graphics processors (GPU). In this first article 10 most recent and widely used interatomic sets of pair potentials (SPP) are assessed by reproduction of solid phase properties of uranium dioxide (UO2) - temperature dependences of the lattice constant, bulk modulus, enthalpy and heat capacity. Measurements were performed with 1K accuracy in a wide temperature range from 300K up to melting points. The best results are demonstrated by two recent SPPs MOX-07 and Yakub-09, which both had been fitted to the recommended thermal expansion in the range of temperatures 300-3100K. They reproduce the experimental data better than the widely used SPPs Basak-03 and Morelon-03 at temperatures above 2500K.