Copyright © GLOBAL 2019 - International Nuclear Fuel Cycle Conference and TOP FUEL 2019 - Light Water Reactor Fuel Performance Conference.All rights reserved. The nuclear fuel cycle consists of multiple processes, including electricity generation, reprocessing, and geological disposal. In addition, various separation technologies have been developed for volume reduction of radioactive waste. Especially from the viewpoint of thermal properties of vitrified waste, the separation of heat-generating nuclides such as cesium (Cs), strontium (Sr), and minor actinides (MA) are considered to be important factors. Furthermore, the separation of molybdenum (Mo) and platinum group metals (PGM) requires consideration of the quality of the vitrified waste and the stable operation of the glass melter. However, the effect of introducing separation processes depends on the nuclide inventory and the amount of high-level waste as well as the conditions of each process in the fuel cycle. Therefore, it is important to clarify the potential impact of separation processes under various conditions of the fuel cycle to reduce the burden on waste management. In this study, we have focused on the separation of Mo, PGM, Cs, Sr, and MA, and investigated their effects on vitrification and geological disposal for extended cooling periods of spent nuclear fuel and increased waste-loading in vitrified waste. The relation between the cooling period and separation was studied to maximize the benefits for the nuclear fuel cycle, especially through reductions of the volume of vitrified waste and the waste-occupied area.