Current and future nuclear power technologies (fission and fusion energy) rely on the success of materials programs for the safe and efficient operation of reactors. Irradiation of materials by energetic particles (e.g., electrons, ions and neutrons) is associated with high energy dissipation, which can drive the underlying nano- and microstructure to evolve under far from thermodynamic equilibrium conditions, resulting in adverse changes of the material’s dimension stability and mechanical and other intended properties. One of the most striking phenomena in this connection is the ability of the material’s nano- and micro- structures to self-assemble in well-organized, two- and three-dimensional periodic arrangements. For example, the ordering of voids into a superlattice having the symmetry of the underlying crystal lattice has been observed in many metals and alloys. And yet, the formation of void lattices remains a controversial subject without a generally accepted theory. The phase-field method based on the principles of the Ginzburg-Laudau kinetic phase-field theory coupled with Cahn-Hilliard diffusion dynamics has enjoyed much success in theoretical predictions of microstructural evolution in recent years. We propose to use this method to investigate the possible controlling processes and parameters that govern the evolution of void ensemble, such as diffusion of vacancies and vacancy clusters, anisotropic diffusion of self-interstitial atoms and clusters, the rate of void nucleation, production and dislocation biases and so on. This presentation will provide some preliminary results from our recent research effort.