The Fukushima Daiichi Accident

238 Pages·2015·7.88 MB·English

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The Fukushima Daiichi Accident
Technical Volume 1/5
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PO Box 100, Vienna International Centre e
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1400 Vienna, Austria t
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Printed in Austria
ISBN 978–92–0–107015–9 (set)
THE FUKUSHIMA DAIICHI ACCIDENT
TECHNICAL VOLUME 1
DESCRIPTION AND CONTEXT OF THE ACCIDENT

i
The following States are Members of the International Atomic Energy Agency:
AFGHANISTAN GERMANY OMAN
ALBANIA GHANA PAKISTAN
ALGERIA GREECE PALAU
ANGOLA GUATEMALA PANAMA
ARGENTINA GUYANA PAPUA NEW GUINEA
ARMENIA HAITI PARAGUAY
AUSTRALIA HOLY SEE PERU
AUSTRIA HONDURAS PHILIPPINES
AZERBAIJAN HUNGARY POLAND
BAHAMAS ICELAND PORTUGAL
BAHRAIN INDIA QATAR
BANGLADESH INDONESIA REPUBLIC OF MOLDOVA
BELARUS IRAN, ISLAMIC REPUBLIC OF ROMANIA
BELGIUM IRAQ RUSSIAN FEDERATION
BELIZE IRELAND RWANDA
BENIN ISRAEL SAN MARINO
BOLIVIA, PLURINATIONAL ITALY
SAUDI ARABIA
STATE OF JAMAICA
SENEGAL
BOSNIA AND HERZEGOVINA JAPAN
SERBIA
BOTSWANA JORDAN
SEYCHELLES
BRAZIL KAZAKHSTAN
SIERRA LEONE
BRUNEI DARUSSALAM KENYA
SINGAPORE
BULGARIA KOREA, REPUBLIC OF
SLOVAKIA
BURKINA FASO KUWAIT
SLOVENIA
BURUNDI KYRGYZSTAN
SOUTH AFRICA
CAMBODIA LAO PEOPLE’S DEMOCRATIC
SPAIN
CAMEROON REPUBLIC
SRI LANKA
CANADA LATVIA
SUDAN
CENTRAL AFRICAN LEBANON
SWAZILAND
REPUBLIC LESOTHO
SWEDEN
CHAD LIBERIA
SWITZERLAND
CHILE LIBYA
SYRIAN ARAB REPUBLIC
CHINA LIECHTENSTEIN
TAJIKISTAN
COLOMBIA LITHUANIA
THAILAND
CONGO LUXEMBOURG
THE FORMER YUGOSLAV
COSTA RICA MADAGASCAR
REPUBLIC OF MACEDONIA
CÔTE D’IVOIRE MALAWI
TOGO
CROATIA MALAYSIA
TRINIDAD AND TOBAGO
CUBA MALI
TUNISIA
CYPRUS MALTA
TURKEY
CZECH REPUBLIC MARSHALL ISLANDS
UGANDA
DEMOCRATIC REPUBLIC MAURITANIA
OF THE CONGO MAURITIUS UKRAINE
DENMARK MEXICO UNITED ARAB EMIRATES
DJIBOUTI MONACO UNITED KINGDOM OF
DOMINICA MONGOLIA GREAT BRITAIN AND
DOMINICAN REPUBLIC MONTENEGRO NORTHERN IRELAND
ECUADOR MOROCCO UNITED REPUBLIC
EGYPT MOZAMBIQUE OF TANZANIA
EL SALVADOR MYANMAR UNITED STATES OF AMERICA
ERITREA NAMIBIA URUGUAY
ESTONIA NEPAL UZBEKISTAN
ETHIOPIA NETHERLANDS VENEZUELA, BOLIVARIAN
FIJI NEW ZEALAND REPUBLIC OF
FINLAND NICARAGUA VIET NAM
FRANCE NIGER YEMEN
GABON NIGERIA ZAMBIA
GEORGIA NORWAY ZIMBABWE
The Agency’s Statute was approved on 23 October 1956 by the Conference on the Statute of the
IAEA held at United Nations Headquarters, New York; it entered into force on 29 July 1957. The
Headquarters of the Agency are situated in Vienna. Its principal objective is “to accelerate and enlarge the
contribution of atomic energy to peace, health and prosperity throughout the world’’.
THE FUKUSHIMA DAIICHI ACCIDENT
TECHNICAL VOLUME 1
DESCRIPTION AND CONTEXT OF THE ACCIDENT

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Printed by the IAEA in Austria
August 2015
STI/PUB/1710

IAEA Library Cataloguing in Publication Data
The Fukushima Daiichi accident — Vienna : International Atomic Energy Agency,
2015.
v. ; 30 cm.
STI/PUB/1710
ISBN 978–92–0–107015–9 (set)
Includes bibliographical references.
1. Nuclear reactor accidents — Analysis. 2. Nuclear power plants —
Accidents — Analysis. 3. Nuclear reactor accidents — Japan — Fukushima-ken.
4. Radioactive pollution — Health aspects — Japan — Fukushima-ken.
5. Radioactive waste management. 6. Emergency management. I. International
Atomic Energy Agency.

IAEAL 15–00988
EDITORIAL NOTE
This publication has been prepared from contributions submitted by many international experts to the five
Working Groups for the preparation of the technical volumes. The content does not necessarily reflect the views
of IAEA Member States, or the organizations nominating experts.
Great care has been taken to maintain the accuracy of information contained in this publication. Neither
the IAEA, nor its Member States, however, assume any responsibility for consequences that may arise from its
use, nor are any warranties made of any kind in connection with this publication.
This publication is not intended to address issues of responsibility, legal or otherwise, for acts or
omissions on the part of any person or entity.
Extracts from this publication may be freely used elsewhere, provided that acknowledgement of the source
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graphics) is from a source or site external to the IAEA, permission for reuse must be sought from the originating
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The use of particular designations of countries or territories does not imply any judgement by the IAEA as
to the legal status of such countries or territories, or of the delimitation of their boundaries, or of their
authorities and institutions.
The mentioning of names of specific companies or products, whether or not indicated as registered, does
not imply any intention to infringe proprietary rights, nor should it be construed as an endorsement or
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The IAEA assumes no responsibility for the accuracy or continued existence of URLs for external or third
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ACKNOWLEDGEMENTS
Financial assistance was provided by Canada, Japan, the Russian Federation, the United Kingdom and
the United States of America.
In-kind contributions were received from Argentina, Australia, Belarus, Brazil, Canada, China, Cuba,
the Czech Republic, Finland, France, Germany, Ghana, Iceland, India, Indonesia, Israel, Italy, Japan,
the Republic of Korea, Malaysia, Mexico, Morocco, the Netherlands, New Zealand, Norway,
Pakistan, the Philippines, Poland, the Russian Federation, Slovakia, South Africa, Spain, Sweden,
Switzerland, the Syrian Arab Republic, Turkey, Ukraine, the United Arab Emirates, the United
Kingdom, the United Republic of Tanzania and the United States of America. In-kind contributions
were also received from the European Commission, the Food and Agriculture Organization of the
United Nations, the International Commission on Radiological Protection, the International Labour
Organization, the International Nuclear Safety Group, the OECD Nuclear Energy Agency, the United
Nations Scientific Committee on the Effects of Atomic Radiation, the World Association of Nuclear
Operators and the World Meteorological Organization.
The Government of Japan provided invaluable support by making available a considerable amount of
information, arranging for Japanese experts to support the work on the report and ensuring logistical
assistance for bilateral meetings in Japan.
The United Nations Scientific Committee on the Effects of Atomic Radiation supported the IAEA by
sharing the relevant database of references from its 2013 report and allowing information and figures
from this report to be reproduced.
The IAEA thanks the large number of experts who were involved in this report. It is the result of the
dedicated efforts of many people. All participants listed at the end of this technical volume made
valuable contributions, but a particularly heavy load was borne by the Co-Chairs and coordinators of
the working groups. The efforts of many expert reviewers, including members of the International
Technical Advisory Group, are also gratefully acknowledged.

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THE REPORT ON THE FUKUSHIMA DAIICHI ACCIDENT
At the IAEA General Conference in September 2012, the Director General announced that the IAEA
would prepare a report on the Fukushima Daiichi accident. He later stated that this report would be
“an authoritative, factual and balanced assessment, addressing the causes and consequences of the
accident, as well as lessons learned”.1
The report is the result of an extensive international collaborative effort involving five working
groups with about 180 experts from 42 Member States (with and without nuclear power programmes)
and several international bodies. This ensured a broad representation of experience and knowledge.
An International Technical Advisory Group provided advice on technical and scientific issues. A Core
Group, comprising IAEA senior level management, was established to give direction and to facilitate
the coordination and review. Additional internal and external review mechanisms were also instituted.
The organizational structure for the preparation of this publication is illustrated in Fig. 1.

FIG. 1. IAEA organizational structure for the preparation of the report on The Fukushima Daiichi Accident.
The Report by the Director General consists of an Executive Summary and a Summary Report. It
draws on five detailed technical volumes prepared by international experts and on the contributions of
the many experts and international bodies involved.
The five technical volumes are for a technical audience that includes the relevant authorities in IAEA
Member States, international organizations, nuclear regulatory bodies, nuclear power plant operating
organizations, designers of nuclear facilities and other experts in matters relating to nuclear power.

1 INTERNATIONAL ATOMIC ENERGY AGENCY, Introductory Statement to Board of Governors (2013),
https://www.iaea.org/newscenter/statements/introductory-statement-board-governors-3.
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The relationship between the content of the Report by the Director General and the content of the
technical volumes is illustrated in Fig. 2.

FIG. 2. Structure of the Summary Report and its relationship to the content of the technical volumes.

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CONTENTS
DESCRIPTION AND CONTEXT OF THE ACCIDENT ..................................................................................... 1 
1. INTRODUCTION ............................................................................................................................................. 1 
1.1. SUMMARY OF THE ACCIDENT ............................................................................................................. 2 
1.1.1. Main occurrences ............................................................................................................................... 3 
1.1.2. Accident initiation and response ........................................................................................................ 5 
1.1.3. Progression of the accident .............................................................................................................. 16 
1.1.4. Stabilization ..................................................................................................................................... 32 
1.2. CONTEXT WITHIN WHICH THE ACCIDENT OCCURRED ............................................................... 34 
1.2.1. Nuclear industry structure ............................................................................................................... 34 
1.2.2. Governmental, legal and regulatory framework of nuclear safety prior to the accident .................. 42 
1.2.3. Stakeholder involvement and public communication ...................................................................... 53 
1.2.4. Training and qualification ............................................................................................................... 55 
1.2.5. Characteristics of the Fukushima Daiichi site ................................................................................. 59 
1.2.6. Description of the Fukushima Daiichi plant systems ...................................................................... 64 
1.2.7. Plant resources and capacity at the time of the accident .................................................................. 81 
1.3. ONSET AND PROGRESSION OF THE ACCIDENT ............................................................................. 86 
1.3.1. Onset of the accident at the Fukushima Daiichi NPP ...................................................................... 86 
1.3.2. Sequence of events at Fukushima Daiichi Units 1–3 ....................................................................... 91 
1.3.3. Sequence of events for the Fukushima Daiichi units in the outage (Units 4–6) ............................ 119 
1.3.4. Sequence of events in the common spent fuel pool ....................................................................... 130 
1.3.5. Sequence of events for the dry cask storage facilities ................................................................... 131 
1.3.6. Sequence of events for the Fukushima Daini Units ....................................................................... 131 
1.3.7. Site to site event comparison ......................................................................................................... 133 
1.4. RADIONUCLIDE INVENTORY AND RELEASES ............................................................................. 134 
1.4.1. Fukushima Daiichi Units 1–3 radionuclide core inventories at the time of accident..................... 135 
1.4.2. Radionuclide release mechanisms .................................................................................................. 142 
1.4.3. Amount of radionuclides released ................................................................................................. 148 
1.4.4. Atmospheric release ...................................................................................................................... 149 
1.4.5. Groundwater and ocean release ..................................................................................................... 154 
1.4.6. Additional radiological release since the accident ......................................................................... 158 
1.5. ACTIONS BY ORGANIZATIONS OTHER THAN TEPCO ................................................................. 163 
1.5.1. Structure and interactions of on-site and off-site organizations .................................................... 163 
1.5.2. Actions by the Prime Minister’s Office and METI ....................................................................... 166 
1.5.3. Actions by NISA and the NSC ...................................................................................................... 171 
1.5.4. Actions by the local governments .................................................................................................. 173 
1.5.5. Actions by international entities .................................................................................................... 174 
1.6. ACTIONS TAKEN IN THE AFTERMATH OF THE ACCIDENT ....................................................... 179 
1.6.1. Actions taken towards stabilization and restoration of the Fukushima Daiichi units .................... 179 
1.6.2. Actions towards a mid-term and long term roadmap for decommissioning .................................. 185 
1.6.3. Government/regulatory actions ..................................................................................................... 189 
1.6.4. Other events at the Fukushima Daiichi site following the accident ............................................... 193 
1.6.5. International actions ...................................................................................................................... 195 
REFERENCES ................................................................................................................................................... 203 
CONTENTS OF CD-ROM ................................................................................................................................ 216
ABBREVIATIONS ............................................................................................................................................ 217 
CONTRIBUTORS TO DRAFTING AND REVIEW ........................................................................................ 221 
INTERNATIONAL TECHNICAL ADVISORY GROUP ................................................................................ 224 
MEETINGS ........................................................................................................................................................ 225 
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