The textbook describes the theory of thermal power plants in relation to nuclear fuel plants. In this regard, issues are considered both common to any thermal power plants, conventional and nuclear, and specific, inherent only to nuclear power plants. The textbook is written on the basis of a generalization of a large literary material of domestic and foreign, including published in the years that have passed since the second edition. Intended for students of the specialty "Nuclear power plants and installations," can be used by engineers working in the design, commissioning and operation of nuclear power plants.