Today, thermal reactors, which are the basis of modern Russian nuclear energy, can consume plutonium, but in limited quantities and with a low content of threshold isotopes, so their fuel supply is actually limited by natural uranium reserves. Fast reactor technology was created for extended production of plutonium and their fuel supply capabilities are limited by the resources of 238U, which is two orders of magnitude more than 235U. The paper presents the following possible functions of fast reactors in the future two-component nuclear energy system, the transition to which in the coming decades is a strategic goal of the Rosatom State Corporation: electricity generation; maintenance the balance of plutonium in the system of fast and thermal reactors; “refinement” of plutonium from spent nuclear fuel in thermal reactors; disposal of long-lived nuclear energy wastes; production of isotopes highly demanded by the industry and medicine. Obviously, the specialized fast reactors creation will be required to increase the efficiency of these functions. As a result, thermal and fast reactors can be used to create a sustainable, multi-functional and waste-free new nuclear power industry with an almost unlimited fuel resource.
