Simulations of self- and Xe diffusivity in uranium mononitride including chemistry and irradiation effects

被引：6

作者：

Cooper, M. W. D. ^{[1
]}

Rizk, J. ^{[1
]}

Matthews, C. ^{[1
]}

Kocevski, V. ^{[1
]}

Craven, G. T. ^{[2
]}

Gibson, T. ^{[2
]}

Andersson, D. A. ^{[1
]}

机构：

[1] Los Alamos Natl Lab, Mat Sci & Technol Div, POB 1663, Los Alamos, MN 87545 USA

[2] Los Alamos Natl Lab, Theoret Div, POB 1663, Los Alamos, MN USA

来源：

JOURNAL OF NUCLEAR MATERIALS | 2023年 / 587卷

关键词：

POINT-DEFECTS; XENON DIFFUSION; FUEL; UO2; NITRIDE; COEFFICIENTS; PLUTONIUM; DIOXIDE; RELEASE; UN;

D O I：

10.1016/j.jnucmat.2023.154685

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

A combination of density functional theory and empirical potential atomic scale simulations have been used to determine a model for defect stability and mobility in uranium mononitride (UN), as a function of temperature (T) and N-2 partial pressure (P-N2). Using the model, predictions of hypo-stoichiometry under U-rich conditions compare favorably to CALPHAD calculations using the TAF-ID database. Furthermore, our predictions of U and N self-diffusivity are in good agreement with experiments carried out as a function of T at specific partial pressures under thermal equilibrium. The validated atomic scale data have then been implemented within a cluster dynamics method to simulate irradiation-enhanced defect concentrations. All defects and clusters studied have significantly enhanced concentrations, with respect to thermal equilibrium, as T is lowered. The irradiation-enhanced Xe diffusivity is compared to post-irradiation annealing and in-pile experiments. The contributions of various defects and clusters to non-stoichiometry, self-diffusivity, and Xe diffusivity are discussed.

引用

页数：15