Development of medium sized ABWRs (ABWR-600, ABWR-900)

Hitachi has been developing medium sized ABWRs as a power source that features flexibility to meet various market needs, such as minimizing capital risks, providing a timely return on capital investments, etc. Basic design concepts of the medium sized ABWRs are 1) using the current ABWR design which has accumulated favorable construction and operation histories as a starting point; 2) utilizing standard BWR fuels which have been fabricated by proven technology; 3) achieving a rationalized design by suitably utilizing key components developed for large sized reactors. Development of the medium sized ABWRs has proceeded in a systematic, stepwise manner. The first step was to design an output scale for the 600 MWe class reactor (ABWR-600) which is appropriate for a distributed power supply. The next step was to develop an uprating concept to extend this output scale to the 900 MWe class reactor (ABWR-900) based on the rationalized technology of the ABWR-600 for further cost savings. (author)