Development of a multiscale thermal conductivity model for fission gas in UO2

JOURNAL OF NUCLEAR MATERIALS

卷:469

Article

Tonks, Michael R.^1,2  Liu, Xiang-Yang³  Andersson, David³  Perez, Danielle²  Chernatynskiy, Aleksandr⁴  Pastore, Giovanni²  Stanek, Christopher R.³  Williamson, Richard² 

[1] Penn State Univ, Dept Mech & Nucl Engn, University Pk, PA 16802 USA

[2] Idaho Natl Lab, Fuel Modeling & Simulat, POB 1625, Idaho Falls, ID 83415 USA

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

[4] Missouri Univ Sci & Technol, Dept Phys, Rolla, MO 65409 USA

关键词: Fuel performance modeling;    Multiscale modeling;    Uranium dioxide;    Thermal conductivity;   

DOI  :  10.1016/j.jnucmat.2015.11.042

来源: Elsevier

【 摘 要 】

Accurately predicting changes in the thermal conductivity of light water reactor UO2 fuel throughout its lifetime in reactor is an essential part of fuel performance modeling. However, typical thermal conductivity models from the literature are empirical. In this work, we begin to develop a mechanistic thermal conductivity model by focusing on the impact of gaseous fission products, which is coupled to swelling and fission gas release. The impact of additional defects and fission products will be added in future work. The model is developed using a combination of atomistic and mesoscale simulation, as well as analytical models. The impact of dispersed fission gas atoms is quantified using molecular dynamics simulations corrected to account for phonon-spin scattering. The impact of intragranular bubbles is accounted for using an analytical model that considers phonon scattering. The impact of grain boundary bubbles is determined using a simple model with five thermal resistors that are parameterized by comparing to 3D mesoscale heat conduction results. When used in the BISON fuel performance code to model four reactor experiments, it produces reasonable predictions without having been fit to fuel thermocouple data. Published by Elsevier B.V.

【 授权许可】

Free