Essential guide to analyzing nuclear energy systems, with focus on reactor physics, fuel cycle, system dynamics, thermal-hydraulics, and economics. Nuclear Reactor Physics and Engineering highlights efforts in utilizing low enrichment uranium fuel as a substitute for carbon-based fuels in energy generation and provides an overview of important aspects of nuclear reactor physics utilizing the neutron diffusion equation for major reactor designs and MATLAB software for system analysis, with exercises illustrating key points and design parameters as supplementary material. This revised and updated Second Edition reflects key findings of the 2023 National Academy of Sciences (NAS) report and discusses physical and engineering characteristics of advanced nuclear reactors, especially in the form of small modular reactors that have the potential to provide enhanced safety and economics, as well as effective long-term management of used nuclear fuel in geological repositories. Key topics explored in the updated edition of Nuclear Reactor Physics and Engineering include: Impact of the use of high-assay low enrichment uranium (HALEU) fuel as a new efficient nuclear fuel Advantages resulting from combined uses of light water reactor and sodium-cooled fast reactor with fuel reprocessing Fundamental nuclear reactor physics, nuclear reactor system analysis, and lattice physics analysis for reactor cores Nuclear fuel cycle analysis, nuclear plant simulation and control, and management of used nuclear fuel Economic analysis of nuclear electricity and thermal-hydraulic analysis of nuclear systems. With a wealth of all-new information detailing the state of the art in the field, Nuclear Reactor Physics and Engineering is an invaluable reference on the subject for undergraduate and graduate students in nuclear engineering, as well as practicing engineers involved with nuclear power plants.