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Title: Impact of grain boundary and surface diffusion on predicted fission gas bubble behavior and release in UO2 fuel

Journal Article · · Journal of Nuclear Materials

In this work, we quantify the impact of grain boundary (GB) and surface diffusion on fission gas bubble evolution and fission gas release in UO2 nuclear fuel using simulations with a hybrid phase field/cluster dynamics model. Here, we begin with a comprehensive literature review of uranium vacancy and xenon atom diffusivity in UO2 through the bulk, along GBs, and along surfaces. In our model we represent fast GB and surface diffusion using a heterogeneous diffusivity that is a function of the order parameters that represent bubbles and grains. We find that the GB diffusivity directly impacts the rate of gas release via GB transport, and that the GB diffusivity is likely below 104 times the lower value from Olander and van Uffelen. We also find that the surface diffusivity impacts bubble coalescence and mobility, and that the bubble surface diffusivity is likely below 10-4 times the value from Zhou and Olander.

Research Organization:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); Idaho National Laboratory (INL), Idaho Falls, ID (United States)
Sponsoring Organization:
USDOE Office of Nuclear Energy (NE); USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR). Scientific Discovery through Advanced Computing (SciDAC); USDOE National Nuclear Security Administration (NNSA)
Grant/Contract Number:
AC07-05ID14517; SC0018359; 89233218CNA000001
OSTI ID:
2382673
Report Number(s):
LA-UR--24-20149; INL/JOU--24-78755-Rev000
Journal Information:
Journal of Nuclear Materials, Journal Name: Journal of Nuclear Materials Vol. 594; ISSN 0022-3115
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English

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