It is vital that Nuclear Power Plants (NPPs) are able to perform with maximum efficiency to optimize fuel utilization. One way of attempting to increase efficiency in NPPs is to implement steam-reheat inside current pressure-channel reactor designs. Therefore, a generic pressure-channel reactor is selected to demonstrate possible options of adding nuclear steam reheat. To support this option, heat transfer in fuel channels of the reactor is analyzed accordingly. This technical book proposes a method to estimate thermal efficiency of a nuclear power plant, and demonstrates an advanced method to analyze heat transfer in a generic pressure-tube type reactor. This book would serve as a supplemental aid for senior-year or graduate-level engineering students interested in this field.