Nuclear power is a highly concentrated energy source that does not emit greenhouse gases and does not affect the climate. In the future, it should hold a significant share in the world energy balance, but this possibility is realized only if the technological problems of closing the nuclear fuel cycle like minimizing the radioactive waste generated and multi-recycling of fissile isotopes are solved. This will make it possible to solve both ecological and economic problems, moving away from deep disposal of long-lived radionuclides to their transmutation, followed by near-surface disposal of short-lived radionuclides.