This revised book covers the fundamentals of thermodynamics required to understand electrical power generation systems, honing in on the application of these principles to nuclear reactor power systems. This text treats the fundamentals of thermodynamics from the perspective of nuclear power systems. In addition to the Four Laws of Thermodynamics, it discusses Brayton and Rankine power cycles in detail with an emphasis on how they are implemented in nuclear systems. Chapters have been brought up-to-date due to significant new results that have become available for intercooled systems and combined cycles and include an updated steam table. The book starts with basic principles of thermodynamics as applied to power plant systems. It then describes how Nuclear Air-Brayton systems will work. It documents how they can be designed and the expected ultimate performance. It describes several types of Nuclear Air-Brayton systems that can be employed to meet different requirements and estimates component sizes and performance criteria for Small Modular Reactors (SMR) based on the Air-Brayton concept. The book provides useful insight into the engineering of nuclear power systems for students and the tabular data will be of great use to practicing engineers.