Staff of the US Nuclear Regulatory Commission walking through areas of the TEPCO’s Plant at Fukushima Daiichi (image credit USNRC, 2014 reproduced under license CC BY 2.0)

risk assessment med hr

False trail to the Root Cause

We’ll brief in the following the incident happened in 2011 in the nuclear power plant at Fukushima Daiichi, Japan, operated by the Tokyo Electric Power Company (TEPCO).   That March 11, 2011 the Author of these notes was in Northern China in an area that, due to the winds, became exposed to the radioactive fallout of Caesium and other isotopes.  Minding an image of the impressive power of the wave invading the Japanese coastal areas that day, the Root Cause should be rapidly labelled as: tsunami.   Then, an effect of an under seabed earthquake.   The earthquakes are notoriously one of those natural phenomena resisting to the scientists' efforts of prediction.  

14 meters Tsunami wave, here seen invading Fukushima's streets, originated by an under seabed  earthquake of magnitude 9.0

Then, as a seemingly logic consequence, the cause for the disaster visible in the figure here on side is natural and unpredictable.  The quintessence of no one is guilt.    It is exactly what the company in charge of the management of that facility, would like to let us agreeing with.  Also what the entire chain of Public auditors and Controllers would like us to be sure.   Tsunami wave resulted in 15884 victims as of February 2014.   Also, a meltdown of three of the plant's six nuclear reactors, a Caesium-137 (and other isotopes) contamination of the air and of the Pacific Ocean's waters.

  Spread of Caesium-137 after Fukushima incident (image credit NOAA, 2011)

The story of this case is more than this and, like we saw in the Chernobyl Case, it was seeded by Conditions long time before.  Looking all around Fukushima and other Japanese nuclear power plants, we discover different Design choices took in the fundamental subjects.  Where to build a dam or a nuclear power plant, is one of those subjects which are studied along years, before to build.  Thoroughly studied for their potential impact, by teams including tens of Geologists and Civil Engineers.   Their proposals later subjected to control by professional Nuclear Regulatory Bodies, before a final decision about what and where to build, and where don’t build anything because too Risky.

 The Design of Japanese nuclear reactors is quite modern, cared and safe

japanese nuclear power plan

Meaning that it is not simply the nuclear reactor Design (see figure on side) what is deeply studied before.   The Design of Japanese nuclear reactors is typically that of a Boiling Water Reactor (BWR) not based over the antiquate risky graphite-technology of Chernobyl, adapt for Military rather than Civil purposes.  Comparing the designs of RBMK at Chernobyl, USSR, and BWR at Fukushima Daiichi, Japan, the last is modern, cared and safe.  Born devoted to generate electricity rather than electricity plus Plutonium for the pits of the implosion-Devices.  In brief, Fukushima’s incident is not due to any Design-related error in the nuclear reactors themselves.

    Operating a TEPCO nuclear reactor.  The blue colour light is Čerenkov radiation, emitted by charged particles (such as an electron) passing through the water at a speed greater than the phase velocity of light in that medium

Focus on the rules of contruction in seismic areas

We suggest to ask yourself why in the highly seismic countries of the World:

  1. is it mandatory to build whatever, not only nuclear power plants, respecting special and particularly expensive safety rules ?
  2. no Insurer shall pay for the consequences of an earthquake to the buildings, if it is later discovered that the safety rules were not applied during the construction ? 
  3. if after an earthquake there are victims, they are trialled all of those who authorised illegal designs and those who built those illegal designs ? 

Focus on the Plant geographic location

It is important to understand that when an incident like Fukushima happens, it is an entire Design, an entire line of thinking which goes forever to ...the trash can of the History.   

 Visibly, all of the Japanese nuclear power plants were designed at the Ocean’s waterfront, ignoring that “tsunami” is a word coined centuries ago in Japan.  These locations optimise the nuclear power plant necessity for huge amounts of cold water, at the expense of …safety.  Readers can be confident that the “tsunami” catastrophic scenario was surely examined when these Plant were designed.   And surely repeatedly cited in the literature as an Achilles-heel for all Japanese nuclear power plants, well before Fukushima's incident.  But, someone preferred to take the Risk because of the economic advantages to be closer than possible to the cooling water.  When incidents have this kind of origin, they are between the most difficult to root cause analyse.  Responsibilities are markedly spread between politicians and administrators. Typically necessary years, spent by Commissions formed to delay the legal effects (credit CC BY-SA 3.0 Unported License)

This kind of location optimises the nuclear power plant's necessity for huge amounts of cold water, always part of its process, at the expense of the safety of operation.   Zooming on the area where the power plant is located, confirms the banality of the Root Cause for the Incident: it is really on the Pacific Ocean shore.  An erroneous assessment of the Risk associated to build an intrinsically riskful plant so close to the Ocean, in a historical highly seismic country like Japan.

  The Root Cause for Fukushima Daiichi incident is all in this image shot before the strictly Design-related disaster (image courtesy TEPCO/2010)

Where a Fukushima-like incident does not happen

“It is important to understand that when an incident like Fukushima happens, it is an entire Design, an entire line of thinking which goes forever to ..…the trash can of the History”

Until now, we cared to see what happened, given a long row of conditions, at Fukushima.   Now, we look around for conditioning states where a Fukushima-like incident could not happen.  And we see immediately that Fukushima is not really the best Design choice.  Its intrisically high level of risk can be perceived after comparing its geographic conditions with those of the other worldwide locations of nuclear reactors.   As an example by the Canadian choice at  Bruce Site, Ontario, Canada.  With its capacity of 6.2 gigawatt electric power, the World’s most powerful nuclear power plant.   There something like what happened at Fukushima, Japan, cannot happen at all not only because Canada is one of the less seismic areas of the planet, rather simply because the Designers who choose Bruce Site, avoided to stay at the waterfront of the Pacific or Atlantic Oceans.   A tsunami could hit the Canadian coasts but, no nuclear power plant should be menaced.   Bruce Site is located on the eastern shore of Lake Huron, in the communities of Inverhuron and Tiverton, Ontario.   Thanks to this Design-related choice, its eight reactors have permanent availability of the huge amount of water in the Laurentian Lakes.

Fukushima’s Root-Cause: Design-related

By the fruits we’ll recognise the tree.  And the tree-like sequence (see figure below) of historical facts yet along the centuries before the incident, was repeating that under the Condition of a highly seismic country, no nuclear power plant should have been built at the Pacific Ocean's waterfront !     Something truer in the country which created the word “tsunami”.    There are a multitude of states, namely conditions, which built up the status in the moment when the Root Cause, the tsunami, acted.   We are representing them in the tree-like figure below.   As an example, it was surely possible to prevent these Effects existing in our memory because part of the past branches we passed through:

  • building the Power Plant at the Ocean waterfront;
  • paying in the Design since the start an extremely high price.   Extremely higher than it was paid.   Much higher price related to the necessity for extremely high barriers of concrete, capable to front a wave of that height, gigantic no-return valves, to assure a normal flow also in the impossibility to discharge water to an Ocean higher than the Plant base, pumps, etc.  

Refer to the figure below, showing a historical tree-like structure around the point “q” corresponding to the content of the slice (or leaf, or sheet) including the Power Plant at Fukushima Daiichi, Japan, on March 11, 2011.   The place where acted the Root Cause named tsunami.   In the figure, each one vertex is a new state of the entire Fukushima Daiichi Nuclear Power Plant.   Thus, mapping one-by-one all possible changes intervened before and after the disaster.   


 Historical tree-like structure around the point “q”  corresponding to the content of the 3-D slice (or leaf, or sheet) including the Power Plant at Fukushima Daiichi, Japan, on March 11, 2011.  The place where acted the Root Cause named tsunami.   As an example in other Future branches: imposing just a brief temporary shut down of the reactor, due to waves peaking at only 1 meter over the cooling water pipings' out feeds, along only 30 seconds of time.  In a multitude of other branches, determining intermediate outcomes, not implying the Ocean's water penetration til the area of the cooling pumps, until damaging them, starting the overheating which provoked the reactor's melt-down and following contamination.

  • Yellow-coloured   subset of all of the initial conditions including the BWR-reactor design and approval; 
  • Red-coloured   unsuccessful subset of all of the outcomes.  Set of all of the branches where a negative effect arose by the Root Cause;
  • Green-coloured   successful subset of all of the outcomes.  Set of all of the branches where a positive effect arose by the Root Cause.

The Reader has to take care of our use of the word state.  Each vertex exists in the state space and cannot be felt in that 4-dimensional useful approximation named physical space, of the higher-dimensional (>9 dimensions) reality.   In the state space each state includes all possible future outcomes.   Meaning that at the point q when and where the tsunami hitted Fukushima Daiichi, all possible future outcomes existed in superposition.   A kind of existence far from our common sense and perception.   One which can only be fully defined in mathematical terms in an abstract space (Hilbert) where all of the possible outcomes of an action “exist before the action”.  

July 5, 2012:  “A man-made accident due to collusion”

Our Root Cause Analysis' conclusions agree with those in the report from the panel.  Chaired by Kiyoshi Kurokawa, former president of the Science Council of Japan, submitted to the both Houses of the Japanese National Diet, concluded the Root Cause for the incident was:

“The TEPCO Fukushima Nuclear Power Plant accident was the result of collusion between the government, the regulators and TEPCO, and the lack of governance by said parties.  They effectively betrayed the nation’s right to be safe from nuclear accidents.  Therefore, we conclude that the accident was clearly ‘manmade,’ (…) 

We believe that the Root Causes were the organizational and regulatory systems that supported faulty rationales for decisions and actions, rather than issues relating to the competency of any specific individual.”

Any residual doubt cleared viewing the account of the events in the video below.  As an example, the special role played by the Emergency Diesel Generators which at Fukushima were disabled by the tsunami flood.   No backup for them, making the following melt down of four reactors unavoidable.   The incident itself should not have happened with the power plant designed in that ill-fated ocean shore, if a second backup Emergency Diesel Generator should have existed, far from the first.  

     Melt-down of the Fukushima Daiichi’s four reactors (courtesy Institute de Radioprotection et de Surete’ Nucleaire, 2012)

A different way to Design

Elsewhere in this website, between other subjects, it has been shown how many interlocked safeties existed in the implosion atomic bomb which burned Nagasaki, Japan.   A device thinked by some of the best minds of the humanity to assure its destructive effect, preventing the undesired effects of an unexpected detonation in their our own hands.    

Links to other Case Studies:

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