Status of Alloy 800H in Considerations for the Gen IV Nuclear Energy Systems

Alloy 800 H is currently under consideration for applications in the next generation nuclear plant (NGNP) at operational temperatures above 750°C. This paper first describes service requirements of the nuclear system for structural materials; and then an extensive review of Alloy 800 H is given on its codification with respect to development and research history, mechanical behavior and design allowables, metallurgical aging resistance, environmental effect considerations, data requirements and availability, weldments, as well as many other aspects relevant to the intended nuclear application. Finally, further research and development activities to support the materials qualification are suggested.