Final Results of United States Advanced Ultra-Supercritical Component Test Project for 760°C Steam Conditions

Following the completion of a 15-year effort to develop and test materials that would allow advanced ultra-supercritical (A-USC) coal-fired power plants to be operated at steam temperatures up to 760°C, a United States-based consortium has successfully completed a project (A-USC ComTest) to help achieve technical readiness to allow the construction of a commercial scale A-USC demonstration power plant. Among the goals of the ComTest project were to validate that components made from the advanced alloys can be designed and fabricated to perform under A-USC conditions, to accelerate the development of a U.S.-based supply chain for key A-USC components, and to decrease the uncertainty for cost estimates of future commercial-scale A-USC power plants. This project was designed to bring A-USC technology to the commercial scale demonstration level of readiness by completing the manufacturing R&D of A-USC components by fabricating commercial scale nickel-based alloy components and sub-assemblies that would be needed in a coal fired power plant of approximately 800 megawatts (MWe) generation capacity operating at a steam temperature of 760°C (1400°F) and steam pressure of at least 238 bar (3500 psia).

The A-USC ComTest project scope included fabrication of full-scale superheater / reheater components and subassemblies (including tubes and headers), furnace membrane walls, steam turbine forged rotor, steam turbine nozzle carrier casting, and high temperature steam transfer piping. Materials of construction included nickel-based alloys (Inconel 740H and Haynes 282) for the high temperature sections. The project team also conducted testing to support ASME Code Stamp approval for nickel-based alloy pressure relief valve designs that would be used in A-USC power plants up to approximately 800 MWe size.

The ComTest project included $27M in scope and was primarily funded by the U.S. Department of Energy (DOE). Work on this project spanned 2015 – 2023. This paper will summarize final project results.