Accessing Macroscopic Timescales with Accelerated Molecular Dynamics

Jacob Eapen¹, Blas P. Uberuaga², and Arthur F. Voter¹
Los Alamos National Laboratory

¹Theoretical Division
²Materials Science and Technology Division

Theoretical understanding of radiation damage and fission product transport entails assessing simulation timescales that are pertinent to reactor operation. Typically, molecular dynamics (MD) simulations are limited to nanoseconds. A set of accelerated molecular dynamics (AMD) methods based on transition state theory (TST), which can assess timescales ranging from microsecond to seconds, has been successfully developed at Los Alamos National Lab. AMDs are particularly attractive for studying radiation damage and fission product transport because they determine the complex diffusion mechanisms and energy barriers directly from the simulations. Since no prior assumptions are made on the diffusion mechanisms, AMDs are well adapted for investigating collective events that arise from neutron interactions and high energy fission recoils. This presentation will show specific results of radiation damage annealing of MgO which shows a surprising spectrum of time scales for seemingly simple defect structures. We will also discuss our new project on the simulation of fission product transport in nuclear fuel.

Contact
Blas P. Uberuaga
Los Alamos National Laboratory
Theoretical Division
Los Alamos, NM 87545
eapen@lanl.gov

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