The Chuetsu-oki Earthquake in Niigata and Safety of the Kashiwazaki-Kariwa Nuclear Power Plant

July 27, 2007

  1. The Chuetsu-oki Earthquake in Niigata prefecture, Japan, which occurred on July 16th 2007, caused widespread damages such as collapse of houses and buildings in the prefecture and its surrounding areas as in Nagano prefecture. It also triggered a fire at an electrical transformer and other problems in the Kasiwazaki-Kariwa Nuclear Power Plant.
  2. However, no problems have been confirmed with regard to the safety of the nuclear reactors as four of the plant’s seven reactors running at the time of the earthquake were all shut down automatically by a safety mechanism.
  3. Due to the earthquake, an insignificant amount of radioactive materials were released from No 7 unit of the plant into the air, and water containing radioactive materials were released from No 6 unit into the sea. But the effect of the radiation due to the release of radioactive materials into the air is as low as one-10 millionth (1/10, 000, 000), and that into the sea is as low as one-billionth (1/ 1, 000, 000, 000) of the radiation which normal citizens would receive from the natural environment in a year, respectively. These radioactivity levels of the releases into the air and the sea are as low as one-millionth(1/1,000,000), and one-100 millionth(1/1,000,000,000), respectively, of the radiation which normal citizens would receive during a round-trip flight from Tokyo to New York. Needless to say, the levels are much lower than the legal limit set by the safety standard, and will never affect the surrounding environment. Furthermore, these leaks have already stopped.
  4. In spite of the facts above, it is most regrettable that some news media have reported on the safety situation surrounding the nuclear power plant in an inaccurate or inappropriate manner, and spread of misperception has produced adverse effects on such fields as tourism in Japan.
  5. Japan has provided and shared relevant information with the International Atomic Energy Agency (IAEA) since the beginning. Considering the proposal by the IAEA that although it is confident in Japan’s ability to perform a thorough assessment of this event, the IAEA is ready to send an international expert team to join Japan in the review, Japan has determined to accept the team from IAEA and to conduct a joint review from  the viewpoint of improving international cooperation in the field of nuclear safety.
  6. We believe that this joint review will not only confirm the current safety of the Kashiwazaki-Kariwa Nuclear Power Plant, more objectively, but also will further contribute to the transparency in Japan’s Nuclear Energy, and help promote to share lessons leaned from the earthquake internationally.