Operational experiences and improved standardization in Japanese boiling water reactor

The nuclear option has been taken for power generation in Japan as a means of clean and stable power supply at an competitive generating cost. Stress has been placed specifically on safety and reliability of nuclear power plants so that the option may widely be accepted in the nation. Boiling water reactors (BWR) have long been achieving an excellent overall performance, which gives a support for nuclear acceptance. The BWR operational experience is reviewed through the latest statistic outlook. It indicates a continuation of improvement in a wide range of performance as a function of elapsing time. The typical aspects of the performance reviewed are plant availability, radiation exposure, and the generation of solid-waste. The Japanese improvement-and-standardization program provided a positive impact that produced a high level of performance as observed in the statistics. The technology evolved in this program was extensively incorporated in the latest BWRs and in the operating units as applicable. A wide stride was stepped out forward toward the further improvement and standardization represented by the development of the advanced boiling water reactor (ABWR). The ABWR incorporates the advanced technology that was supported either by the BWR operating experience or by the confirmatory tests performed in the development program. Through the ABWR development and its currently on-going project application engineering, the international cooperation has been tightly maintained between Hitachi, Ltd. and Toshiba Co. of Japan and General Electric Co. of the United States. Tokyo Electric Power Company, Inc. has placed the ABWR in its schedule for construction of the sixth and the seventh unit of its Kashiwazaki-Kariwa Nuclear Power Station (K-6 and -7). (author)