High-temperature alloys for the power conversion loops of advanced HTRs

The aim of this paper is to survey the effort to define the high-temperature alloys for nuclear process heat plants in the Federal Republic of Germany (FRG) and the corresponding effort for the gas turbine HTR in the FRG and in Switzerland. The service conditions in the different components, such as the thermal insulation, turbine blades, steam reformer tubes and the heat exchangers of steam gasification and hydrogasification plants are first outlined. Special attention is given to the likely impurities in the primary coolant gas and their influence on the corrosion of metals. Secondly, a survey of the candidate alloys for use at high temperatures is given. The development of alloys specifically designed for HTR use is mentioned. Finally, the nature and extent of the work needed to select and characterize the alloys for the different applications are summarized. (author)