Report
Main Text
Table of contents
Ⅰ. Introduction
1. Purpose of the Investigation Committee
2. Committee Members
3. Basic Principles of the Investigation Committee
4. Activities of the Investigation Committee
5. Topics addressed by the Investigation Committee
6. The position of this Interim Report and plans for further activities by the Investigation Committee
Ⅱ. Overview of Accident at the Fukushima Dai-ichi Nuclear Power Station
1. Overview of the Fukushima Dai-ichi Nuclear Power Station
2. Tohoku District - off the Pacific Ocean Earthquake and Tsunami Produced by the Earthquake
3. Overview of Damage at the Fukushima Dai-ichi NPS as Revealed by Investigation So Far
4. Overview of Damage Caused by the Accident at the Fukushima Dai-ichi NPS
Ⅲ. Emergency Responses Required and Taken by Governments and Other Bodies
1. Emergency responses mandated in the Nuclear Emergency Preparedness Act,
the Basic Plan for Emergency Preparedness, etc.
2. Government response after the Accident
3. Response Taken by Fukushima Prefectural Government after the Accident
4. TEPCO's Response after the Accident
5. Response of the Off-site Center After the Accident
Ⅳ. Accident response at TEPCO's Fukushima Dai-ichi NPS
1. Situation and response from the time the earthquake hit until the arrival of the tsunami
(from approximately 14:46 to 15:35 on March 11, 2011)
2. Situation and response during the period from the arrival of the tsunami to the special event
occurrence report as stipulated in Section 1, Article 15 of the Act on
Special Measures Concerning Nuclear Emergency Preparedness
(from approximately 15:35 to approximately 17:12 on March 11, 2011)
3. Situation and response during the period from the specific event occurrence report according
to Paragraph 1, Article 15 of the NEPA until the explosion of the Unit 1 R/B
(from approximately 17:12 on March 11 to 15:36 on March 12, 2011)
4. From the explosion at the Unit 1 R/B until the explosion at the Unit 3 R/B
(from approximately 15:36 on March 12 until 11:01 on March 14)
5. From the explosion in the Unit 3 R/B until the pressure drop of Unit 2 S/C and the explosion
in the Unit 4 R/B (from around 11:01 on March 14 until 06:10 on March 15)
6. After the S/C pressure decrease of Unit 2 and the explosion in the Unit 4 R/B
(after around 06:10 on March 15)
7. Hydrogen gas explosion in the R/B(outside the Primary Containment Vessel)
Ⅴ. Emergency Response Measures Primarily Implemented outside the Fukushima Dai-ichi Nuclear Power Station in Response to the Accident
1. Environmental radiation monitoring
2. Utilization and dissemination of information yielded by SPEEDI
3. Evacuation of Citizens
4. Measures taken to address the risk of radiation exposure
5. Contamination of agricultural, livestock, marine products, the air, soil and water
6. Occurrence and treatment of contaminated water
7. Estimates of the total amount of radioactive materials discharged and an evaluation of INES levels
8. Details of events in areas where there may be problems with the provision of information to the public
9. Details of events in areas where there may be problems concerning the provision of information
to the international community
10. Coordination with other countries and the IAEA
Ⅵ. Items to be considered in terms of prevention of accidents and expansion of damage
1. Japanese safety regulations concerning nuclear installations, etc.
2. Countermeasures against earthquakes
3. Whole concept of tsunami countermeasures
4. The role of countermeasures against severe accidents
5. Basic ideas concerning tsunami protection and severe accident management measures
6. Response to nuclear emergency in the midst of complex disaster
7. Issues concerning the function of NISA as a regulatory agency
8. Issues concerning the role of the NSC
Ⅶ. Observations and Proposals Regarding Problems Identified through Investigations and Inquiries to Date
1. Introduction
2. General description of problems identified during investigation and inquiry into the accident
3. Problems in the responses of government bodies after the Accident
4. Problems of responses to the accident at the Fukushima Dai-ichi NPS
5. Problems of hazard control measures
6. Inappropriate precautionary measures against tsunami and severe accidents
7. Why were the measures against tsunami and severe accident insufficient?
8. Recommendations on a new nuclear safety regulatory body
9. Recapitulation
10. Conclusion
Attachments
Table of contents Ⅱ① Ⅱ② Ⅳ Ⅴ Ⅵ Other
