Thursday, March 10, 2016

Fukushima Nuclear Meltdowns Five Years On

Subtitle: Fukushima Design Flaws Should Not Have Existed

 The 9.0-magnitude earthquake off north-eastern Japan on March 11, 2011 occurred five years ago to the day.  The 50-foot tsunami that followed the earthquake had devastating consequences to a large area in Japan, especially knocking out the grid power and disabling the emergency power to several of the six nuclear reactors at the Fukushima power complex.   As is well-known today, three of the reactors melted down, three containment buildings exploded, and great quantities of nuclear radiation were released into the air, the soil, and the ocean.   Radioactive water continues to leak into the ocean even today.  

SLB has a post from 2014 on the Fukushima nuclear disaster, titled "Fukushima - The Disaster That Could Not Happen."  (see link).   This is article 22 of the 30-article series on Truth About Nuclear Power (that presently has more than 21,000 pageviews). 
Fukushima nuclear reactors after meltdowns and explosions
March 11, 2011 (credit: ORNL)

While pausing to offer condolences to those who lost loved ones, and whose lives were changed for the worse, this article discusses a few additional aspects of what went wrong and what lessons should be learned. 

In simplest terms, sheer stupidity created the Fukushima nuclear meltdowns.   There are essentially no lessons that were taught that day, beyond what competent engineers already knew and know.   The lesson is: nuclear designers and advocates should not be trusted with the safety aspect of nuclear plants. 

First, it was well-known that a nuclear power plant requires a considerable water supply and means to circulate that water for cooling a reactor after a shutdown.   It was equally well-known that a loss of grid power could occur, in fact, that is the very reason that emergency generators are installed in nuclear power plants.   Fukushima had the emergency generators.  It was also well-known that diesel fuel is required to run the emergency generators.  Fuel was stored on-site, but only sufficient fuel for 8 to 10 hours for each reactor.  It was also well-known that Japan is prone to earthquakes and tsunamis.  In fact, some of the nearby areas have or had tsunami protection systems such as seawalls, and gates that could close to prevent water from entering a river valley.    So much for not knowing what to do if power is lost, and not knowing about earthquakes and tsunamis at Fukushima. 

What was incredibly wrong was the emergency generators and batteries were in the basement of the buildings, where seawater flooded them and made them inoperable.  

It was also a bad decision to design the plants to withstand a tsunami of only 20 feet, when it was well-known that earlier tsunamis were much higher.  The actual tsunami was approximately 50 feet high.   Historical tsunamis in Japan include one from 1896 that was 30 to 38 meters (100 to 130 feet); in 1933 the tsunami was 21 meters (70 feet approximately).   There can be no excuse for building Fukushima reactors to withstand a tsunami of only 20 feet.  

It should be noted that elevating the entire plant another 30 to 40 feet adds a trivial amount to the construction cost.   In the alternative, constructing a water-tight wall with appropriate openings also would add a trivial amount to the construction cost. 

From the ORNL paper referenced in the earlier SLB post, (see link), the tsunami design portion has strange wording that leads to even more unease about Japanese nuclear designs:

"At the target site, the height of the design tsunami should exceed all the
calculated historical tsunami heights.

 ...the design tsunami is compared with the historical records …. it is confirmed
the height of the design tsunami that is obtained in this paper is twice that of

historical tsunamis on an average”  --  (see p. 14 of the ORNL paper linked above)

Several things are wrong with this statement.  "At the target site," should not be used for the design basis, instead, "in the general area" would give a much safer design.   

Next, "should exceed all the calculated historical tsunami heights" should be "exceed all the actual historical tsunami heights."     There is, or should be, sufficient evidence in a long-populated country like Japan to know, not have to guess or calculate tsunami heights.    

Finally, "it is confirmed ... is twice that of historical tsunamis ON AN AVERAGE."  This is so wrong it beggars belief.  One does not design a plant to meet the average conditions, instead, one designs for the worst case.  

It is clear from the evidence that a nearby nuclear power plant, also part of the Fukushima complex, managed quite well during and after the earthquake and the tsunami.  That reactor was built on higher ground and had an emergency generator that functioned long enough.   

What is also abundantly clear is that nuclear industry professionals are not to be trusted with their assurances that reactors are designed, built, and operated safely.   There is a great need for independent, competent engineers to review the designs and actual construction, and especially the design basis, to identify problems such as existed at Fukushima and went undetected for decades.  

Roger E. Sowell, Esq.
Marina del Rey, California  

Copyright (c) 2016 by Roger Sowell, all rights reserved

1 comment:

Jon T said...

Should not engineers be put on trial for this .The knowledge that this may happen may stiffen their resolve to face of the accountants!