Startup and Operation of a Supercritical Carbon Dioxide Brayton Cycle

Bechtel Marine Propulsion Corporation (BMPC) is testing a supercritical carbon dioxide (S-CO₂) Brayton system at the Bettis Atomic Power Laboratory. The 100 kWe integrated system test (IST) is a two shaft recuperated closed Brayton cycle with a variable speed turbine driven compressor and a constant speed turbine driven generator using S-CO₂ as the working fluid. The IST was designed to demonstrate operational, control, and performance characteristics of an S-CO₂ Brayton power cycle over a wide range of conditions. Initial operation of the IST has proven a reliable method for startup of the Brayton loop and heatup to normal operating temperature (570 °F). An overview of the startup process, including initial loop fill and charging, and heatup to normal operating temperature is presented. Additionally, aspects of the IST startup process which are related to the loop size and component design which may be different for larger systems are discussed.