Fundamentals of nuclear reactors

Nuclear power plants produce energy basically through nuclear fission reactions in nuclear fuel. When fission reactions occur in the fuel material, a large amount of heat is produced along with several neutrons and fission fragments, thus leading to a fission chain reaction and energy production. This chapter provides a basic understanding of nuclear reactor principles. The first part begins with a basic concept of nuclear power plants beginning with the fundamentals and practical applications related to the utilization of nuclear energy from fission. It explains the different types of neutron interaction with matter including neutron attenuation, scattering, and fission. The concepts of neutron diffusion and reactor theory are explained starting with equation of continuity and Fick’s law approximation in one-energy group, multigroup, and two-group contexts. Then, a brief introduction to nuclear reactor kinetics including reactor reactivity, neutron life, reactor feedback coefficients, and neutron poisons is explained. The second part of the chapter explains the basic principles of nuclear system thermal hydraulics with single-phase fluid mechanics and heat transfer relevant to nuclear systems. This part includes topics ranging from basic thermal hydraulic characteristics of power reactors to the main classification of nuclear power plants, power cycles and reactor designs, and primary coolant system in various reactor designs. The chapter then discusses thermal design principles and reactor heat generation, which leads to a more focused thermal analysis of nuclear fuel elements including a brief description of the single-phase heat transfer for laminar and turbulent flow in both circular and noncircular subchannels.