Preliminary considerations of modified 9Cr-1Mo steel for Gen IV nuclear reactor application

Modified 9Cr-1Mo steel is currently identified as one of the leading candidate materials in the down selection for construction of the Gen IV nuclear reactor pressure vessel. Because of the stringent requirements in strength, size, safety, design life, and maintenance for the intended nuclear application, qualification of the material demands scrutiny in various aspects such as mechanical properties, data sufficiency, Codification, mechanical behavior modeling, metallurgical stability, environmental resistance, component manufacturability and transportation. In the present paper, history of the material development is briefly reviewed; requirements and challenges for the intended application are discussed; available information on the material is described. Further research and development activities are suggested to facilitate the materials selection.