Time-Dependent Neutronics in Structural Materials of Inertial Fusion Reactors and Simulation of Defect Accumulation in Pulsed Fe and SiC

New results are presented on the time-dependent neutron intensities and energy spectra from compressed inertial fusion energy (IFE) targets and in structural Fe walls behind typical IFE chamber protection schemes. Protection schemes of LiPb and Flibe have been considered with two different thicknesses, and neutron fluxes in the outer Fe layer as a function of the time from target emission are given. Differences between the two solutions are noted and explained, and the effect of thickness is quantitatively shown. Time-dependent defect characterization of the Fe layer under pulse irradiation is presented. A new well-established multiscale modeling procedure injects, at the appropriate dose rate, damage cascades in a kinetic Monte Carlo lattice (microscopic) to study defect diffusion, clustering, and disintegration. The differences with a continuous irradiation for a still low fluence of irradiation are presented. Experimental validation of a multiscale modeling approach has been recognized and proposed in the Spanish VENUS-II project by using Fe ions on pure and ultrapure Fe. To study similar problems in SiC, new tools are needed to quantify the kinetic defects; results leading to the validation of a new tight binding molecular dynamics code for SiC are presented.