Investigation of point defects diffusion in bcc uranium and U–Mo alloys

• Published in: Journal of nuclear materials Vol. 458; pp. 304 - 311
• Main Authors: Smirnova, D.E., Kuksin, A.Yu, Starikov, S.V.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2015
• Subjects: Alloys; Body centered cubic lattice; Diffusion; Energy of formation; Formations; Mathematical analysis; Point defects; Simulation
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2014.12.080

We present results of investigation of point defects formation and diffusion in pure γ-U and γ-U–Mo fuel alloys. The study was performed using molecular dynamics simulation with the different interatomic potentials. The point defects formation and migration energies were estimated for bcc γ-U and U–9wt.%Mo alloy. The calculated diffusivities of atoms via defects are provided for pure γ-U and for the alloy components. Analysis of simulation results shows that self-interstitial atoms play a leading role in the self-diffusion processes in the materials studied. This fact can explain a remarkably high self-diffusion mobility observed experimentally for γ-U. The self-diffusion coefficients in γ-U calculated in this assumption agree with the data measured experimentally. It is shown that alloying of γ-U with Mo increase formation energy for self-interstitial atoms and decelerate their mobility. These changes lead to decrease of self-diffusion coefficients in U–Mo alloy compared to pure U.