– Japanese government compiled report on Fukushima nuclear accident (Denki Shimbun, June 14, 2011):
TOKYO –The Japanese government prepared a report on the accident at the Fukushima I nuclear power station (NPS) of Tokyo Electric Power Co., Inc. (TEPCO) and submitted it to the International Atomic Energy Agency (IAEA) on June 7. The findings will be reported at the IAEA ministerial conference due to start on June 20. The 750-page report outlines several facts and observations including the developments of the accident, Japan’s nuclear safety regulatory framework, radiation exposure situations and lessons learned from the accident, and states at the conclusion that “Japan has recognized that a fundamental revision of its nuclear safety preparedness and response is inevitable.” As part of plans for the fundamental revision, the report declares that the Japanese government will separate the Nuclear and Industrial Safety Agency (NISA) from the Ministry of Economy, Trade and Industry (METI) and start reviewing the administration of nuclear safety regulations.
The report consists of 13 themes. In the introduction, it points out that “the situation has become extremely severe” in dealing with the Fukushima I accident, due to the circumstances where the accident had to be dealt with in parallel with reconstruction work following the disaster caused by the great earthquake and tsunami. The report also includes an apology in relation to the nuclear accident, stating, “Japan sincerely regrets causing anxiety for people all over the world about the release of radioactive materials.”
Regarding the details of the accident, the report explains all data obtained so far in chronological order along with their analytic results. In addition to the outline and developments of the accident, the report details the current status of Fukushima I units 1 to 6. The status of other nuclear power plants damaged by the Great East Japan Earthquake is also described in the report, including the Fukushima II NPS, the Higashidori NPS operated by Tohoku Electric Power Co., Inc., and the Tokai II NPS operated by the Japan Atomic Power Company. The report also provides information on radioactive materials leaked into the air and sea, and devotes many pages describing the current situation regarding radiation exposure, for which reporting had been requested by IAEA.
According to the report, the total number of radiation workers who have been engaged in emergency work at Fukushima I is about 7,800 as of May 23. The workers were exposed to approximately 7.7 mSv on average, and there are thirty people who have been recorded as receiving doses over 100 mSv. It is noted, however, that delays have been reported in the measurement of internal exposure, and there is a possibility that a certain number of workers may later be found to have dose levels exceeding 250 mSv, which is the dose limit set by the Japanese government for working in emergency operations.
As for the provisional evaluation based on the International Nuclear Event Scale (INES), the report concludes that the evaluation should have been made and communicated more promptly and accurately, citing the fact that although level 3 was issued initially, the severity level was raised in stages and it took one month before level 7 was finally announced.
The report details the lessons learned so far from the accident in terms of 28 items, which are categorized into five groups to aid comprehensive grasping. The five categories are 1) strengthening of preventive measures against severe accidents, 2) enhancement of response measures against severe accidents, 3) enhancement of nuclear emergency responses, 4) reinforcement of safety infrastructure and 5) thorough instillation of safety culture.
As for the preventive measures against severe accidents, the report points out the necessity for enhanced measures against tsunamis and earthquakes and securing of power sources, and admits that “the accident management measures have been insufficient.” It states an intention to redesign the preventive measures by means of laws and regulations.
As regards the response measures against severe management, the report calls for enhancement of measures against hydrogen explosion and exposure control systems under accident conditions. As to the nuclear emergency responses, the report declares that Japan will enhance environmental monitoring and clarify the roles of the government and the relevant local agencies.
For the reinforcement of safety infrastructure, the report says that the government will start reviewing issues such as separating NISA from METI and integrating it with the Nuclear Safety Commission and the relevant departments of the Ministry of Education, Culture, Sports, Science and Technology.
Lastly, the report stresses that the government will support the personnel combating the Fukushima accident with all its strength and that “a fundamental revision of Japan’s nuclear safety measures will be inevitable.” It says, “It is necessary for Japan to conduct national discussions on the proper course for nuclear power generation while disclosing the actual costs of nuclear power,” including the costs of taking the 28-item measures to ensure the safety of nuclear power generation and other measures to deal with the accident.