AbstractAmong the advantages offered by the deployment of thick liquid walls (LW) in high power density reactors is the substantial reduction in radwaste volume and hazard that is mainly attributed to the extended lifetime of structural materials. In this paper, we quantitatively estimate the volume of the generated waste when different thick LWs are used. In particular, we make a comparison of the radwaste volume between lithium and Flibe as potential candidates for deployment as the thick LWs in high power density reactors (10 MW/m2). In addition, the volume of the generated waste is compared with the corresponding volume in two conventional solid wall (SW) blankets with low wall load (LWL, 5 MW/m2) and high wall load (HWL, 10 MW/m2). In this assessment exercise, the blankets under consideration were optimized first such that adequate tritium breeding ratio (TBR) is obtained and the same level of magnet protection against radiation damage is reached. This initial optimization step was necessary to arrive at consistent comparisons. It is shown that using LWL conventional SW blanket generates ∼10% more waste volume per unit height than that generated with the lithium LW concept while ∼35% more waste volume is generated if the HWL conventional SW blanket is deployed. On the other hand, it is shown that the thick Li LW option generates total waste whose volume is a factor of ∼1.3 larger than the one with the thick Flibe option which has superior neutron moderating capabilities compared with lithium.