Multiscale modeling of fission gas behavior in U3Si2 under LWR conditions

JOURNAL OF NUCLEAR MATERIALS

卷:522

Article

Barani, T.¹  Pastore, G.^2,3  Pizzocri, D.¹  Andersson, D. A.⁴  Matthews, C.⁴  Alfonsi, A.²  Gamble, K. A.²  Van Uffelen, P.⁵  Luzzi, L.¹  Hales, J. D.² 

[1] Politecn Milan, Dept Energy, Nucl Engn Div, Via La Masa 34, I-20156 Milan, Italy

[2] Idaho Natl Lab, POB 1625, Idaho Falls, ID 83415 USA

[3] MIT, Dept Nucl Sci & Engn, 77 Massachusetts Ave, Cambridge, MA 02139 USA

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

[5] European Commiss, Joint Res Ctr, Directorate Nucl Safety & Secur, POB 2340, D-76125 Karlsruhe, Germany

关键词: Nuclear fuel modeling;    Uranium silicide;    Accident tolerant fuels;    Fission gas behavior;    Multiscale modeling;    Fuel performance codes;   

DOI  :  10.1016/j.jnucmat.2019.04.037

来源: Elsevier

【 摘 要 】

In this work, we present a model of fission gas behavior in U3Si2 under light water reactor (LWR) conditions for application in engineering fuel performance codes. The model includes components for intra-granular and inter-granular behavior of fission gases. The intra-granular component is based on cluster dynamics and computes the evolution of intra-granular fission gas bubbles and swelling coupled to gas diffusion to grain boundaries. The inter-granular component describes the evolution of grain-boundary fission gas bubbles coupled to fission gas release. Given the lack of experimental data for U(3)Si(2 )under LWR conditions, the model is informed with parameters calculated via atomistic simulations. In particular, we derive fission gas diffusivities through density functional theory calculations, and the re-solution rate of fission gas atoms from intra-granular bubbles through binary collision approximation calculations. The developed model is applied to the simulation of an experiment for U3Si2 irradiated under LWR conditions available from the literature. Results point out a credible representation of fission gas swelling and release in U3Si2. Finally, we perform a sensitivity analysis for the various model parameters. Based on the sensitivity analysis, indications are derived that can help in addressing future research on the characterization of the physical parameters relative to fission gas behavior in U3Si2. The developed model is intended to provide a suitable infrastructure for the engineering scale calculation of fission gas behavior in U3Si2 that exploits a multiscale approach to fill the experimental data gap and can be progressively improved as new lower-length scale calculations and validation data become available. (C) 2019 Elsevier B.V. All rights reserved.

【 授权许可】

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