Lessons Learned From Fukushima Dai-ichi (4. Summary. 2011. 12. 25)




Uploaded by H2OProjectBBT on 21.03.2012

Transcript:
Hello everyone, I am Kenichi Ohmae.
After the Fukushima Dai-ichi-reactor accident,
I personally have made many statements about this problem on such places as YouTube,
and as I talked about these things with Nuclear Power Oversight Minister Hosono, I told him that
I would like to make a proposal for analysis towards this accident, and recurrence prevention. All I needed was access to the resources.
This is different from the Accident Invetigation Board organaized by the government,
and my investigation and proposal are made completely from the standpoint of the taxpayer.
It just so happens that I have learned about nuclear reactors at graduate school.
I have also been involved in the designing of nuclear reactors, so I volunteered to take on this project.
I reported my results to Nuclear Power Oversight Minister Hosono on October 28th,
and we also conducted a joint press conference together.
As for the results of the Interim Report, by disclosing everything on YouTube and other web sources,
the total 189 page report was submitted.
And regarding what happened to the PWR after that, I spent another 1 month to investigate,
including the case study of whether the same natural disaster that happened to Fukushima Dai-ichi were to happen again,
and in this case I had the cooperation of Kansai Electric Power Co., Inc. and Mitsubishi Heavy Industries, Ltd..
With the submission of this report to Minister Hosono on December 21st, 2011,
the final report, or final report as a second opinion, has been concluded.
Therefore, after completing this operation, or string of operations,
I would like to quickly report my thoughts here.
Regarding the full report, the final report, and PWR,
I would like to do so in a different YouTube site.
I have summarized a few points on my thoughts through this string of operations. These are shown below.
The first one is
that the fundamentals of the existing nuclear reactors' design concepts must be changed drastically.
This point refers to the setting conditions and the prerequisite conditions.
I believe that the prerequisite conditions for building nuclear reactors should be done away with.
In other words, the process of setting prerequisite conditions such as a certain tsunami height,
or certain earthquake strength,
and then building the nuclear reactor based on that should be abolished.
Those prerequisite conditions imply that there are certain limitations to critical resources,
such as power, that would be secured to this extent but not so to the extent over it and so on.
But in the case of a nuclear reactor, no matter what happens, the cooling system must be secured.
And in order to secure that, the power sources,
water sources, or cooling sources substituting water must remain functioning whatever condition or event happens as well.
So, building and designing nuclear reactors based on certain prerequisites
such as an earthquake of level 8, or a 10 meter tsunami should be done away with.
The world' s nuclear reactors have all been built in this old way,
so the design concept of nuclear reactors all over the world must be radically changed.
I think it can be said that the harshest lesson learnt from Fukushima Dai-ichi was that all of the nuclear reactor design concepts were erroneous.
And as for the stress tests,
if the previous conclusion is acceptable,
then setting up predicted accidents and investigating how well the nuclear reactors
can endure that accident are also old concepts.
Yes, this kind of operation is still necessary, but after Fukushima Dai-ichi it is not enough.
In other words, the test can not investigate whether the reactor can withstand unexpected accidents.
Therefore, although it is necessary, it is not enough.
For that reason, the current stress tests cannot apply the lessons we have learned at Fukushima Dai-ichi,
and it can be said that it will be hard to gain the approval of the local citizens and public.
We put together such a detailed report regarding
the BWR, Boiling Water Reactor, which was the reactor type at Fukushima Dai-ichi.
We learned in this investigation that our findings and proposals can also be applied to the PWR,
Pressurized Water Reactor, as well.
When the severe accident occurred on March 11th at Fukushima Dai-ichi,
due to the complete loss of all the AC/DC power sources,
the instrument and reactor situations could not be fully monitored or understood.
Especially regarding locations where multiple reactors are built in one place,
such as Fukushima Dai-ichi where 6 nuclear reactors are in one plant,
it was difficult to comprehend which devices were working, which valves were opened or closed,
what operations were possible or not, etc.
Beyond that, in this case where all the power was lost, and decisions needed to be made under extremely poor conditions,
the accident surely contains an aspect of a man-made disaster to some extent,
but it was more like the workers wrestled with the completely broken nuclear reactor.
It became a fight between human and reactors.
And, in the Accident Investigation Board, accusations such as "This and that could have been done."
or "It should have been done in some other way", would be heard
but these are hindsight,
and if nuclear reactors are to be activated again, comprehensive perspicuity is a crucial key.
Out of all of the equipment, the status of all devices must be observable.
If there is some sort of a priority list, operators can make decisions on where to facilitate the minimum required water
or the minimum required power. For example, "this section is in a more critical situation" and so on.
In order to make these decisions without complicated speculation, comprehensive clarity is necessary.
There wasn' t enough comprehensive clarity, or the capability to overview multiple reactors simultaneously,
such as 4, 5, or 6, and in Kashiwazaki Kariwa Plant' s case there were 7 reactors.
Even now, such a clarity does not exist,
but if an extreme accident like the one at Fukushima occurs,
it is necessary for the plant director to make a decision with simple clarity when the time comes.
And later on, of course it can be said, "This should have been done at this point.",
but as those of you who drive a car know, in the spur-of-the-moment, appropriate decisions cannot be made, and accidents tend to expand greatly.
So, in that way, a design or mechanism to assess the plant' s total situation becomes necessary.
Another issue is that after the Fukushima accident until this day,
no one, not even the supervisory agency's responsible officials,
has taken responsibility for the accident.
However, the fact we obtained from our analysis is
that the greatest cause of this accident was the long-term loss of power.
Both alternate and direct current power sources
were lost over a long period of time in the Fukushima case,
but it is written in the Nuclear Safety Agency's official design guideline
that such a long-term loss of alternate power does not need to be considered.
This is obviously an error in the design concept,
and the fact that such a concept was published in the design guideline has been connected directly to the severe accident.
The reason why it led directly to the severe accident was not because of the tsunami,
but of this design guideline. Due to this, the reactors could not endure against the tsunami.
Based on these facts, I believe it will become important to make it clear which supervisory agency is responsible for the design mistake.
And it might become an important job of the Accident Investigation Board to find the person responsible,
even though it might be someone from the past, and for them to take responsibility.
As a citizen of this country, the fact that after such catastrophic event the person responsible for this accident still has not stepped forward,
that no one has been penalized and they are still going about their regular work, causes me to feel indignation.
The cause and result of this accident should be fixed and broadcasted around the world.
That is to say, we believe that
the lessons of Fukushima Dai-ichi are in actuality the lessons that should apply to all nuclear reactors.
These are not specific to Fukushima,
or only to Japan, but can and should be applied to all the nuclear reactors around the world.
The reason is that at present Japan' s government is broadcasting to the world and to the IAEA that this accident was brought about because of
the unimaginable and unexpected size of the earthquake, and the unexpected size of the tsunami.
And if this is the case, the world may be led into a false sense of security.
In other words, people may say, "Such a big earthquake, or tsunami won't come to our country.",
or "First of all, our country's nuclear reactors are located near a river so tsunami's won't occur there", so they are relieved.
But let us say instead of a tsunami, if terrorists attack, or if a plane crashes into a reactor,
and the pipes are destroyed, or the lines are disconnected,
and in the case of terrorists, the electrical systems are destroyed - a long-term loss of power such as at Fukushima can be considered easily,
and it would mean the sudden loss of the cooling systems.
Even in these cases,
the lesson learnt from Fukushima - that the power and cooling systems must be secured in all severe circumstances - should be shared around the world.
We would like to share the knowledge and countermeasures that are in our proposals with the world' s nuclear operators to consider
as lessons from Fukushima so they won't so reassured.
In that sense, I would like all the stakeholders to radically re-state the messages from Japan regarding lessons learned in the way
as stated in our proposals. That is the main point of our report today.
Regarding the contents, I will report them in detail in a separate YouTube site.
All the resources up to the interim report have been already shared and can be downloaded from the YouTube and the internet.
The site and YouTube address that this final report
can be downloaded from will be introduced here,
so for those of you who are interested in it,
please take a look.
Also, the detailed resources are available for download, so please take a look at those as well.
We would be honored if you would take our final report into your considerations.
Thank you very much.
Special thanks to: Ms Jewel Naruse Ms Seiko Toyama Mr. Curtis Hoffmann Ms Keiko Sato