Recent Research & Development on the Supercritical Carbon Dioxide Brayton Cycle at Argonne National Laboratory

by Jim Sienicki1, Anton Moisseytsev1, Dae Cho1, Matthew Thomas2, Rick Vilim1, Yoichi Momozaki1, Steve Lomperski1, & Mitch Farmer1
1Argonne National Laboratory
2Kansas State University

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Development of the supercritical carbon dioxide (S-CO2) Brayton cycle at Argonne National Laboratory (ANL) is ongoing for application to Sodium-Cooled Fast Reactors (SFRs), Lead-Cooled Fast Reactors (LFRs), and Very High Temperature Reactors (VHTRs) with a focus upon realization of the benefits to be gained from improved plant economics, efficiency, and safety. Both experiment and analysis activities are being carried out. Performance testing of a Printed Circuit Heat ExchangerTM (PCHETM, Heatric, a subsidiary of Meggitt (UK), Ltd.) was recently completed for CO2-to-CO2 heat exchange under prototypical low temperature recuperator conditions. A one-dimensional steady state heat exchange model for compact diffusion-bonded heat exchangers incorporating zigzagged channels has been developed and compared with the data. A Small Sodium Test Loop has been constructed and operated to provide data on the potential for plugging of straight semicircular microchannels for sodium flow similar to those in a Na-to-CO2 PCHE under postulated accidents resulting in the formation of sodium oxide impurities in the sodium as from air ingression. A new heat exchanger testing facility is being designed to obtain data on heat transfer to CO2 under prototypical high temperature recuperator conditions with the CO2 heated by sodium in a small-scale Na-to-CO2 heat exchanger. Design of a facility for performance, endurance, and thermal shock testing of full-size Na-to-CO2 compact diffusion-bonded heat exchanger modules is in progress. The ANL Plant Dynamics Code has been developed for system level transient analysis of reactor plants incorporating a S-CO2 Brayton cycle power converter. The code is being utilized for the analysis of operational transients and postulated accidents to understand the transient behavior of the S-CO2 Brayton cycle for specific reactor types, and to verify and refine the ANL S-CO2 Brayton cycle control strategy for specific reactor types. The one-dimensional compressor modeling incorporated in the code is being compared with available data from the Gen IV Sandia National Laboratories (SNL) small-scale compressor tests carried out at Barber-Nichols, Inc. and SNL. Preliminary comparisons have led to specific improvements in the model formulation which manifest for smallscale turbomachinery. A second and faster running simulation code has been developed at ANL for scoping-type calculations. The G-PASS/CO2 code allows the loop configuration and plant control system to be specified through the input deck facilitating quick study of prototype designs. The code models are being benchmarked against SNL test loop data. The purpose of this presentation is to provide an overview of the ANL research and development activities. For specific topics, more detailed information and results can be found in accompanying presentations and papers at the Symposium.