This technical report presents an overview of nuclear reactor maintenance to be used in planning a nuclear reactor. There are certain basic maintenance fundamentals that are common to all types of reactors that may be' incorporated in a power producing facility. Basically, there are only two types of maintenance procedures. The direct type, which is common to conventional steam plants, may be used in some areas where the radioactivity is low enough. In most parts of the plant, maintenance will of necessity be remote due to the high level of radioactivity. For simplicity of description in this report all reactor types are divided into two general classes: solid fuel types and circulating fuel types. The report lists nine types of reactor power plant types with advantages and disadvantages maintenance-wise of each.