Toward Post-Fukushima No. 4

4. Fukushima Accident. A View from Russia
Andrey Ovcharov
Head of the Nuclear Fuel Cycle Department,International Business Relations, LLC, Russia

I got first news about the accident form the BBC

all of the invited experts repeatedly said that theworld news channel shortly after the first explosion

containment was intact there was no danger ofon 12 March 2011. I had been hearing from theradioactive

leaks

intothenews that there were some problems at a couple ofpersonallywasnotimpressed

Japanese NPPs but the scale of recent tsunami andexplanations and remained fully convicted thatthe destruction and loss of life it had caused totallysomething very serious had happened. At that time

eclipsed for me the importance of these problems.

all experts, TEPCO and the IAEA insisted that theThe now famous video with the fist massive

accident

explosion at Unit 1 actually stunned me as I thinkincomparable to the Chernobyl or even to theit stunned every Russian who has some relation toThree Mile Island accident.

wasarelativelyenvironment.”byinsignificantItheseonethe nuclear industry. We do not have a video of theexplosion at Chernobyl NPP but the scale ofI found some technical information about BWR

explosion and subsequent damage to the reactor

containment Mark I and read it and it seemed tobuilding seemed comparable and associations withme that there was no relieve valve from thethat tragic event in now distant 1986 instantly

containment (more properly dry and wet wells) tocame to my mind.

the structure on the top of the reactor building
where the explosion took place. Moreover I

The first comments of invited experts on both thepersonally would have expected to see a hydrogenBBC and local Russian TV channels were strangely

explosion in the stack near the building if there

optimistic, it seemed that they were discussing a

was a dedicated relief valve designed to provide aminor event that would not have any consequenceswayin terms of radioactive contamination and loss ofradioactive gases directly into the environment inlife. The best of experts’ explanations went to thecase of a serious accident. The idea, if it is a design

following. “There had been some loss of waterfeature, to allow such gases to bleed from thecirculation due to a failure of the emergency diesel

containment into the top part of the reactor

generator and there had been water vapor reacting

building was too queer for me to believe at thatwith zirconium rods of the fuel assemblies for somepoint.

for

bleeding

untreatedand

potentiallytime yielding hydrogen. The pressure of hydrogen
inside the reactor vessel had been building up andThe second massive explosion on March 14, 2011

leaked to upper part of reactor building when it

was another surprise for me. Watching the video ofexploded. Thus, the explosion was very strong butthe explosion on YouTube I noticed that the color of1

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Toward Post-Fukushima No. 4smoke during explosion was darker and there was

Later I found that a number of researches on thesome yellow flame at the moment of explosion. As I

behavior of Mark I had been made before thehad seen many small explosions of hydrogen I

accident. The most recent one was accomplished inknow that pure hydrogen normally explodes

2010, just before the tragedy. All these researches

without any smoke and color just like it was duringpredicted that at some point during an accident

the explosion at Unit 1. Consequently, I thought

involving the loss of coolant circulation there wouldthat something was actively burning inside thebebuilding before the explosion, perhaps cables orcontainment into the building, specifically into theeven the polyether foam lining of the containment

top structure. It seems that some panels of thatwall. The last supposition was an especially direstructure even were designed to provide ventilation

one as it meant that reactor core might have been

in case of an accident so it seems that the events

molten then melted through the bottom of thethat lead to the explosions had been considered asreactor vessel and finally fell on the floor below thea probable scenario. There are proven methods toreactor vessel.

oxidize

bleedingofhydrogen

explosive

gases

containing

fromgases

thewithout

explosions but no such systems seem to be provided
After the second explosion it became evident thatto function in the design of the Fukushima NPP.

the fact that spent fuels in these reactors wasMoreover it seems that the vent lines did notstored in a pool inside the top superstructures

function well for bleeding excessive gases from thedestroyed by the explosions also had very serious

containment to the stack.

consequences if these fuel assemblies became
exposed to the environment and it seemed that

Thus, there are many questions concerning thecoolant circulation and make-up for these pools

original design and, especially, the fact that allstopped.

subsequent reviews and licensing procedures failed
to address these issues and move the diesel

During all these events it was regularly reported

generators to a right place preventing the total loss

that diesel generators were damaged in theof power in the first place and then to provide atsunami and their failure was the onset of all thesystem preventing massive hydrogen explosions

subsequent events. This gives rise to two principalthat destructed the buildings and exposed spentquestions. If a strong tsunami after an earth quake

nuclearwas considered as a probable option in the safetymeasures that should have been taken would notanalysis (and it seems absolutely improbable thathave been prohibitively expensive for the plant’s

it was not), why all the generators were installed inoperator but they seemingly were not considered atplaces where they can be damaged. We can seeall.

fuelpooltotheenvironment.

Theseveral small hills near the plant and it is difficult
to see why the generators were not installed on one

I am no expert in nuclear reactor design but, atof these hills in a relative safety. Another question

the same time, I’m not a stranger to the problems

arises from the fact that for many days emergencyof the nuclear power. After the Chernobyl disaster

services were unable to deliver new generators andthe safety review and licensing procedures became

connect them. In such an industrialized country

more rigorous, perhaps even too rigorous. Tons ofwith numerous ports and floating cranes it seems

papers have been compiled and thousand ofstrange.

man-years spent on safety analysis and related2

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Toward Post-Fukushima No. 4

simulations but when the day of reckoning came it

The questions about the Fukushima accident

became evident that any amount of paper work

posed in this essay might have been asked by any

cannot be a substitute to real safety systems andof the leaders of the anti-nuclear movement in any

good design decisions. As a result, the trust of thecountry of the world and the world nuclear

public to all the safety reviews and licensing

industry as a whole must provide objective,

procedures

nucleardetailed and independently reviewed answers toindustry has been deeply undermined and it is notthese questions if it wants to make a lesson of theclear what action should the industry take now to

accident and find a place for one of the greatest

win back the public opinion. It is evident that we

technological achievements of XXth century - thecannot make the licensing procedures even more

nuclear power - in the post-Fukushima world.

adoptedbythemodern

complex as they are prohibitively complex already.
Yet, we see that an absolutely predictable andAugust 2011quite probable event - a strong earthquake with asubsequent tsunami on the Eastern shore of Japan- in real life led to the second most serious accident
in the history of civil nuclear power. Perhaps formanyyearstheindustry

has

been

more

concentrated on the consideration of improbable
events like the Deluge in New Mexico or a 9.0
magnitude earthquake in Northern Russia andother negligible events instead of a hands-on
approach to realistic accident scenarios?

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