Contact Author:
Prof. Kune Y. Suh
kysuh@snu.ac.kr
P:82-2-880-8324
F:82-2-889-2688
San 56-1 Sillim-dong
Gwanak-gu
Seoul, 151-742
Korea
Supercritical Carbon Dioxide Brayton Power Conversion Cycle Design for Optimized Battery-Type Integral Reactor System
Myoung S. Sohn, Won J. Kim, Tae W. Kim, Kune Y. Suh (Seoul National University)
Supercritical carbon dioxide (SCO2) promises a high power conversion efficiency of the recompression Brayton cycle due to its excellent compressibility reducing the compression work at the bottom of the cycle and to a higher density than helium or steam decreasing component size. Therefore, the high SCO2 Brayton cycle efficiency as high as 45% furnish small sized nuclear reactors with the many economical benefits on the plant construction and maintenance. The Seoul Nation University (SNU) has started to develop 23 MWth BORIS (Battery Optimized Reactor Integral System) as a multi-purpose reactor. BORIS, an integral-type optimized fast reactor with an ultra long life core, is coupled to the SCO2 Brayton cycle needing smaller space relative to the Rankine steam cycle because of its small components. The SCO2 Brayton cycle of BORIS consists of a 16 MW turbine, a 32 MW high temperature recuperator, a 14 MW low temperature recuperator, an 11 MW precooler and 2 and 2.8 MW compressors. Entering six heat exchangers between primary and secondary system at 19.9 MPa and 390¡É, the SCO2 leaves from heat exchangers at 19.9 MPa and 550¡É. The promising secondary system efficiency of 45% was calculated by using a theoretical method in which the main parameters include pressure, temperature, heater power, the turbine¡¯s, recuperators¡¯ and compressors¡¯ efficiencies, and the flow split ratio of SCO2 going out from the low temperature recuperator. To develop advanced techniques needed to adopt the shell-and-tube type heat exchanger in the secondary loop of BORIS, the SNU is developing the test loop christened as SOLOS (Shell-and-tube Overall Layout Optimization Study) to experimentally study the SCO2 behavior from both thermal and hydrodynamic points of view. Concurrently, CFD (Computational Fluid Dynamics) code analysis is being conducted to developing an optimal analytical method of the SCO2 turbine efficiency having the parameters of flow characteristics of SCO2 passing through buckets of turbine. These simultaneous experimental and analytical methods for designing the secondary loop of BORIS can supply optimal solution for developing a new battery-type integral nuclear power reactor system.