Improved Understanding of First-Wall Vaporization-Condensation in Inertial Confinement Fusion Reactors

We report approximate x-ray and debris spectra emanating from a region of compressed DT fuel representing the imploded configuration of a generic direct-drive ICF reactor pellet. We show how the spectra are modified by spherical lead shields of various thicknesses placed near the pellet, and show that it is not possible to lessen the ablation of the first wall or blanket of a low-pressure ICF reactor chamber through use of such shields. Then we report that the calculated x-ray spectra alone (i.e., without the associated debris) cause vaporization of a first wall placed at a radius of 4 m that is much more than previously expected. This result increases the importance of understanding the details of the vaporization and condensation phenomena.