TODAY’S STUDY: THE CAUSES OF FUKUSHIMA

Interim Report on the Accidents at Fukushima Nuclear Power Stations of Tokyo Electric Power Company
December 26, 2011 (Investigation Committee)

Executive Summary

Chapter--Introduction…

The Investigation Committee on the Accidents at the Fukushima Nuclear Power Stations (“the Investigation Committee”) of Tokyo Electric Power Company (TEPCO) was established by the Cabinet decision on May 24, 2011. Its objectives are: to conduct investigation and evaluation for finding out the causes of Accidents at the Fukushima Dai-ichi Nuclear Power Station (Fukushima Dai-ichi NPS) and Fukushima Dai-ni Nuclear Power Station (Fukushima Dai-ni NPS) of TEPCO as well as the causes of accident damage; and to make policy recommendations for limiting the expansion of damage and preventing reoccurrence of similar accident.

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The Investigation Committee has conducted its investigation and evaluation since its first meeting on June 7, 2011. Its activities included: site visits to the Fukushima Dai-ichi and Dai-ni NPSs, as well as to other facilities; hearing of heads of local governments around the Fukushima Dai-ichi NPS; and hearing of people concerned through interviews mainly by the Secretariat. As of December 16, 2011, the number of interviewees reached 456.

The investigation and evaluation by the Investigation Committee are still ongoing and the Interim Report does not cover every item that the Committee aims at investigating and evaluating. Fact-finding of even some of those items discussed in the Interim Report are not yet completed.

The Investigation Committee continues to conduct its investigation and evaluation and will issue its Final Report in the summer of 2012…

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Chapter--Outline of the Accidents…

On March 11, 2011, the Fukushima Dai-ichi and Dai-ni NPS were hit by the Off the Pacific Coast of Tohoku Earthquake (“the Earthquake”) and accompanying tsunami waves (“the Tsunami”). The Earthquake was of Magnitude 9.0 and the Tsunami waves height at the Fukushima Dai-ichi NPS exceeded 15 meters above O.P. (Reference sea level at Onahama Peil).

Six nuclear power units stood at the Fukushima Dai-ichi NPS: Units 1 to 3 were in operation, and Units 4 to 6 were in maintenance modes at the time of the Earthquake. Units 1 to 3 appeared to have automatically scrammed at the Earthquake, but external power supplies and almost all in-house AC power supplies were lost due to the Earthquake and the Tsunami. Reactors and spent fuel pools at the Fukushima Dai-ichi NPS lost their cooling capabilities. Explosions occurred on Units 1, 3 and 4, which were caused presumably by the hydrogen released from the possible core damage and filled in the reactor buildings. The reactor core of Unit 2 also seems to have been damaged, although the investigation is still incomplete.

A large amount of radioactive materials were released and spread from the
Fukushima Dai-ichi NPS. The zone up to 20km from the site was designated as the
Access Restricted Areas and no entry is allowed unless authorized. Some areas outside
20km from the site were also designated as the Deliberate Evacuation Areas. As many
as more than 110,000 people have evacuated. Many people are still forced to live in
evacuation, and radiation contaminations have caused serious impacts in extended
areas.

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Chapter--Why were the measures against tsunami and severe accident insufficient?..

1-Limitation of voluntary safety measures

TEPCO did not incorporate measures against tsunamis exceeding the
design basis. This indicates the limit of voluntary safety measures.

2-Insufficient organizational capabilities of regulatory bodies
Relevant research and knowledge continue to advance quickly and on
daily basis. The regulatory bodies should focus their efforts on
formulating and updating the guidelines and standards, taking into
account the latest knowledge to be applicable. To this end, it is essential
to ensure sufficient organizational capabilities of regulatory bodies.

Scholarly discussion with inconclusive nature could be left to the work by
academic society.

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3-Negative effects of specialization and division of labor

Excessive fragmentation by specialization may have negative effects for
designing measures against tsunami, which requires knowledge and
technology of diverse disciplines. Coordinated efforts by diversified
knowledge and expertise coming from various cultural backgrounds are
important. Organizational system of breaking barriers of specialization
should be devised.

4-Difficulty in presenting risk information

It is a paradox that effort to improve and search for higher safety is met
with negative reactions by others, because such effort may be interpreted
as disallowing past practices.

It is not easy to admit an absolute safety never exists and to learn to
live with risks. But it is necessary to make effort toward realizing a
society where risk information is shared and people are allowed to make
reasonable choices.

Chapter--Recommendations on the new nuclear safety regulatory body

The Government made a cabinet decision on August 15, 2011 to
reorganize the nuclear safety regulatory bodies into an agency of the
Ministry of Environment, by separating NISA from METI and integrating
the functions of the NSC. The Investigation Committee requests the
Government to take the following points into account in establishing the
new regulatory body.

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1-Independence and transparency

The new regulatory body is required to ensure its independence and
transparency. It should be provided with necessary authority, resources and
staff with expertise to enable to perform its function independently. It should
bear accountability on nuclear safety to the nation.

2-Organizational competence in responding to an emergency
The new regulatory body is required to formulate disaster prevention
programs and implement disaster prevention training so that it can carry out
activities promptly at the time of disaster. It is necessary to develop
professional competence to provide appropriate advice and leadership to the
responsible personnel and relevant organizations that are in charge of
emergency response. Their management capabilities need to be promoted to
make best use of available resources effectively and efficiently.

It is also important to have strong sense of responsibilities for managing an
emergency. It must prepare for organizational system in advance to enable
itself to respond to a large-scale disaster. The new regulatory body also needs
to prepare, in collaboration with relevant government agencies and local
governments, for the system by which the entire organizations concerned
work together for managing an emergency as a team. In this set-up, the role
of the new regulatory body is to be clarified.

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3-The role of providing information

The new regulatory body should realize deep sense of the importance of
providing relevant information. It should put the system in place routinely
and be prepared for providing timely and appropriate information to the
nation and the international community in an emergency.

4-Securing of competent human resources and staff education for upgrading
Management of human resources and personnel planning are necessary to
enable its staff to formulate consistent career path. Specific steps to this end
should include: improved conditions to securing competent staff with high
professional expertise; enlarged opportunities for its staff to experience
long-term training and practical study; personnel exchanges with other
administrative authorities or research institutions including those for nuclear
and radiation activities.

5-Collection and accumulation of scientific knowledge

It should continue to acquire knowledge relevant for regulatory needs by
monitoring relevant academic societies and specialized scientific journals
including those overseas, as well as the activities of other regulatory bodies in
the international community. It should try to appreciate the significance of
such information, and share, utilize, preserve and transfer systematically
within the new regulatory body.

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Chapter--Preliminary conclusions…

The Investigation Committee is of the view, from its investigation and evaluation
up to now, that the following three factors had major influence over many problems
relating to the Accidents and the responses after the Accidents.

1-Lack of severe accident measures against tsunami

TEPCO did not take precautionary measures in anticipation that a severe
accident could be caused by tsunami such as the one hit at this time. Neither did
the regulatory authorities.

Even for an accident of low probabilities so long as extremely large scale
damages are anticipated once it occurs such as the tsunami of this time, due
consideration should be given to the risks involved and precautionary measures
should be taken.

2-Lack of viewpoint of complex disaster

It was a major shortcoming for the safety of both nuclear power plants and
surrounding communities that nuclear accident had not been assumed to occur as
complex disaster. Disaster prevention program should be formulated by assuming
complex disaster, which will be the major point in reviewing nuclear power plant
safety for the future.

3-Lack of viewpoint of looking at the whole picture of accident

It cannot be denied that viewpoint of looking at a whole picture of an accident
was not adequately reflected in nuclear disaster prevention program in the past.
The nuclear disaster prevention program had serious shortfalls. It cannot be
excused that the nuclear accidents could not be managed because of an
extraordinary situation that the tsunamis exceeded the assumption.

The Investigation Committee is convinced of the need of paradigm shift in the
basic principles of disaster prevention programs for such a huge system, which may
result in serious damage once it has an accident.

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Chapter--Closing…

Whatever to plan, design and execute, nothing can be done without
setting assumptions. At the same time, however, it must be recognized
that things beyond assumptions may take place. The Accidents this time
present us crucial lessons on how we should be prepared for such incidents
beyond assumptions.

The Investigation Committee will continue its investigation and
evaluation, bearing in mind that many people are still obliged to spend
restricted life in evacuation for a long period of time, suffering from
radiation contamination or fears of health due to exposure, contaminated
air, soils, water and food.