During the international effort to develop the next generation nuclear reactor technologies, many new power cycle concepts were derived to improve efficiency and reduce the capital cost. Among many innovative power cycles, it was identified that the supercritical CO2 (S-CO2) Brayton cycle technology has a big potential to outperform the existing steam cycle and eventually replace it. The S-CO2 cycle achieves high efficiency with very compact size, which is the ultimate advantage for a power cycle to have. The S-CO2 cycle has a great potential not only for the future nuclear applications but also for general heat sources such as coal, natural gas, and concentrated solar. In this paper, a brief introduction to the S-CO2 power cycle technologies will be first provided, and a short summary of current research and development status of the power cycle technology around the world will be followed. Especially the research works performed by KAIST, KAERI and several related research institutions in Korea will be reviewed in more detail, since they have recently developing a strong infrastructure to test these ideas by constructing a demonstration facility while producing many innovative ideas to improve and realize the concept.