[en] The present state-of-the-art and trends in development of nuclear power in the USSR are analyzed. The operating experience of the RBMK and WWER type reactors is highlighted. The development of the reactors proceeds along the way of increasing reactor unit power and reliability. Due to their favorable electricity generating cost structure the channel graphite reactors are most suitable for operation at off-peak loads. The thermal efficiency of the RBMKs with supercritical vapor parameters (240 kg/cm², 540 deg C) can be increased to approximately 44%. Nonetheless the prospects of further increase of the efficiency are connected with the development of gas-cooled high-temperature reactors, both thermal and fast. Some problems of nuclear district heating and process heat are discussed. Different aspects of reactor safety under conditions of variable loads are considered, ensuring resistance of structural materials to brittle and viscous destruction being in the spot light. Investigation of all aspects of nuclear power complexes is pointed out to deserve attention