The Fukushima Daiichi Nuclear Accident : Final Report of the AESJ Investigation Committee

The Magnitude 9 Great East Japan Earthquake On March 11, 2011, Followed By A Massive Tsunami Struck Tepco's Fukushima Daiichi Nuclear Power Station And Triggered An Unprecedented Core Melt/severe Accident In Units 1 - 3. The Radioactivity Release Led To The Evacuation Of Local Residents, Many Of Whom Still Have Not Been Able To Return To Their Homes. As A Group Of Nuclear Experts, The Atomic Energy Society Of Japan Established The Investigation Committee On The Nuclear Accident At The Fukushima Daiichi Nuclear Power Station, To Investigate And Analyze The Accident From Scientific And Technical Perspectives For Clarifying The Underlying And Fundamental Causes, And To Make Recommendations. The Results Of The Investigation By The Aesj Investigation Committee Has Been Compiled Herewith As The Final Report. Direct Contributing Factors Of The Catastrophic Nuclear Incident At Fukushima Daiichi Npp Initiated By An Unprecedented Massive Earthquake/ Tsunami - Inadequacies In Tsunami Measures, Severe Accident Management, Emergency Response, Accident Recovery And Mitigations - And The Underlying Factors - Organizational Issues, Etc., Have Been Clarified And Recommendations In The Following Areas Have Been Made. - Nuclear Safety Fundamentals - Direct Factors Of The Accident - Organizational Aspects - Common Items (r&d, International Cooperation, Human Resources Management) - Post-accident Management/recovery From The Accident.--page [4] Of Cover. Introduction -- Overview Of Nuclear Power Station -- Overview Of The Accident At The Fukushima Daiichi Nuclear Power Station -- Overview Of Events Occurring At Power Stations Other Than The Fukushima Daiichi Nuclear Power Station -- Off Site Response -- Accident Analysis And Issues On Nuclear Safety System -- Root Causes Of The Accident And Recommendations -- Post-accident Management In Progress. Atomic Energy Society Of Japan, Editor. Includes Bibliographical References And Index. "The Magnitude 9 Great East Japan Earthquake on March 11, 2011, followed by a massive tsunami struck TEPCO's Fukushima Daiichi Nuclear Power Station and triggered an unprecedented core melt/severe accident in Units 1 - 3. The radioactivity release led to the evacuation of local residents, many of whom still have not been able to return to their homes. As a group of nuclear experts, the Atomic Energy Society of Japan established the Investigation Committee on the Nuclear Accident at the Fukushima Daiichi Nuclear Power Station, to investigate and analyze the accident from scientific and technical perspectives for clarifying the underlying and fundamental causes, and to make recommendations. The results of the investigation by the AESJ Investigation Committee has been compiled herewith as the Final Report. Direct contributing factors of the catastrophic nuclear incident at Fukushima Daiichi NPP initiated by an unprecedented massive earthquake/ tsunami - inadequacies in tsunami measures, severe accident management, emergency response, accident recovery and mitigations - and the underlying factors - organizational issues, etc., have been clarified and recommendations in the following areas have been made. - Nuclear safety fundamentals - Direct factors of the accident - Organizational aspects - Common items (R & D, International cooperation, human resources management) - Post-accident management/recovery from the accident."--Page 4 of cover Front Matter....Pages i-xii Introduction....Pages 1-6 Overview of Nuclear Power Station....Pages 7-17 Overview of the Accident at the Fukushima Daiichi Nuclear Power Station....Pages 19-42 Overview of Events Occurring at Power Stations Other Than the Fukushima Daiichi Nuclear Power Station....Pages 43-67 Off-Site Response....Pages 69-120 Accident Analysis and Issues....Pages 121-423 Analysis and Issues on Nuclear Safety System....Pages 425-467 Root Causes of the Accident and Recommendations....Pages 469-493 Post-accident Management in Progress....Pages 495-536 Back Matter....Pages 537-560 4.1 The Fukushima Daini Nuclear Power Station4.1.1 Overview of the Fukushima Daini Nuclear Power Station; 4.1.2 Overview of the Earthquake and Tsunami; 4.1.3 Influence of the Seismic Ground Motion and the Tsunami; 4.1.3.1 Influence of the Seismic Ground Motion on the Power Station; 4.1.3.2 Influence of the Tsunami on the Power Station; 4.1.4 Response Before the Arrival of the Tsunami; 4.1.5 Response After the Arrival of the Tsunami; 4.1.5.1 Reactor Cooling Responses After the Arrival of the Tsunami; 4.1.5.2 Cooling of the Containment Vessel Pending Restoration of the Heat Removal Function 4.1.5.3 Restoration Plan Based on the Walkdown4.1.5.4 Emergency Material Procurement; 4.1.5.5 Restoration of the Heat Removal Function and Achievement of Cold Shutdown; 4.2 The Onagawa Nuclear Power Station; 4.2.1 Overview of the Onagawa Nuclear Power Station; 4.2.2 Overview of the Earthquake and Tsunami; 4.2.2.1 Observed Earthquake and Tsunami; 4.2.2.2 Earthquake Observation Record; 4.2.2.3 Tsunami Observation Record; 4.2.3 Influence of the Seismic Ground Motion and Tsunami; 4.2.3.1 Collapse of the Unit 1 Heavy Oil Storage Tank; 4.2.3.2 Fire on the Unit 1 High-Voltage Power Panel (M/C) 2.2 Overview of Facilities in the Power Stations Other Than the Fukushima Daiichi Nuclear Power Station2.2.1 The Fukushima Daini Nuclear Power Station; 2.2.2 The Onagawa Nuclear Power Station; 2.2.3 The Tokai Daini Nuclear Power Station; Chapter 3: Overview of the Accident at the Fukushima Daiichi Nuclear Power Station; 3.1 Damage Caused by the Earthquake and Tsunami; 3.2 Unit 1; 3.3 Unit 2; 3.4 Unit 3; 3.5 Unit 4 and Spent Fuel Pools; 3.6 Unit 5 and Unit 6; Chapter 4: Overview of Events Occurring at Power Stations Other Than the Fukushima Daiichi Nuclear Power Station Preface; Contents; Chapter 1: Introduction; 1.1 Background to the Establishment of the AESJ Investigation Committee; 1.2 Activities of the AESJ Investigation Committee; 1.3 Structure of the Report; Chapter 2: Overview of Nuclear Power Station; 2.1 Overview of Facilities in the Fukushima Daiichi Nuclear Power Station; 2.1.1 Main Facilities Including Safety Equipment; 2.1.1.1 Overview of the Power Station; 2.1.1.2 Safety Equipment and Others at Power Stations; 2.1.1.3 Emergency Power Supply Facilities; 2.1.1.4 The Cooling System in the Event of a Reactor Isolation 2.1.1.5 Equipment, etc. to be Discussed in the Next and Subsequent Chapters2.1.2 Facilities for Accident Management Measures; 2.1.2.1 Severe Accident; 2.1.2.2 Introduction of Severe Accident Measures to Japan; 2.1.2.3 Severe Accident Measures in Fukushima Daiichi; 2.1.3 Seismic Resistant Design and Tsunami Resistant Design for Facilities; 2.1.3.1 The Regulatory Guide for Reviewing the Safety Design of Light Water Nuclear Power Reactor Facilities; 2.1.3.2 Seismic Resistant Design; 2.1.3.3 Tsunami Resistant Design 4.2.3.3 Inundation of Unit 2 Nuclear Reactor Auxiliary Machine Cooling Water B-System Pump and the High Pressure Core Spray Au