In March 18, rating of the INES on the events in Fukushima Dai-ichi Nuclear Power Station, by the Tohoku Regional Pacific Ocean Offshore Earthquake is temporary estimated Rating 5. However, Nuclear and Industrial Safety Agency (NISA) estimated total amount of discharge from Fukushima Dai-ichi NPS, using the analytical result of the state of nuclear reactor under the cooperation of Japan Nuclear Energy Safety Organization (JNES). As a result of re-evaluation, total amount of discharged I131 is estimated at 1.3E17Bq, and Cs137 is estimated at 6.1E15Bq. Hence NISA concluded that the rating of the accident would be equivalent of Rating 7.
This result is present status of discharge from Fukushima Dai-ichi NPS. Because discharge is on going and the amount of discharge from each reactor is unspecified, NISA will continuously be gathering information and evaluate them.