Mitsubishi Heavy Industries, Ltd. has been developing "SRZ-1200" as a state-of-the-art nuclear power plant to be constructed after the Fukushima Daiichi Accident. The SRZ-1200 is an advanced light water reactor designed to achieve a level of safety as high as rationally achievable by incorporating safety measures derived from lessons learned from the Fukushima Daiichi Accident and various advanced technologies, including molten core cooling systems. We have nearly completed the basic design of the SRZ-1200 and is currently preparing for verification of the technologies and the detailed design activities. The development of individual technologies and design progress are detailed in other reports.