Multiscale modeling hierarchically links various computational techniques over widely differing length and time scales.159 Multiscale modeling of He trans­port, fate, and consequences requires linking ab initio electronic structure, MD, kinetic Monte Carlo/Lattice Monte Carlo (KMC/KLMC), and mean field RT simulations to predict microstructural evolutions as an ultimate basis for modeling mechanical behavior. (see Chapter 1.08, Ab Initio Electronic Structure Calculations for Nuclear Materials; Chapter 1.09, Molecular Dynamics; Chapter 1.14, Kinetic Monte Carlo Simulations of Irradiation Effects; Chapter 1.15, Phase Field Methods and Chapter 1.16,

Dislocation Dynamics) In this section, we emphasize electronic-atomistic models of He behavior in Fe lattices.