Chernobyl and Fukushima the biggest nuclear catastrophes in history which brought home
the ghastly consequences of nuclear gone wrong. Which of these was worse?
This video will illustrate and compare both events and answer this question.
Chernobyl Nuclear Power Station is in Northern Ukraine. This reactor was the
infamous RBMK type. It was next to the Dnieper river which provided cooling
water. At the time of the disaster in 1986 it was part of the Soviet Union.
The Fukushima Daichi nuclear power station is on the Pacific coast of Japan 200km
north of Tokyo. These reactors were an early American reactor design.
Chernobyl unit 4 was just two and a half years old when it exploded.
The Fukushima plant had been running for 40 years when the disaster struck.
Chernobyl had 4 graphite moderated reactors. They were simpler technology and without a
containment structure. Reactor 4 was busy shutting down and was at just 6% power.
A sudden runaway power surge occurred that blew up the Reactor Core tearing its building apart.
Pieces of reactor were strewn all around in the most out of control radiation release ever seen.
An uncontained graphite fire burned for days ejecting fine radioactive fuel fragments
high into the atmosphere. The Fukushima plant had 6 water moderated reactors.
4, 5 and 6 were shut down and undergoing maintenance. Units 1, 2 and 3 were producing electricity on that day.
The 13m high tsunami wave knocked out power to the cooling Loops. Without cooling water
the reactor overheated and melted. The molten core generated hydrogen gas which accumulated
in the upper service area. The hydrogen exploded blowing up the upper level of reactor building 1.
This happened 24 hours after the tsunami.
Unlike at Chernobyl, the reactor contents remained
shielded inside the containment. On the 3rd day the same happened to unit 3.
The flying debris lifted more than 300m into the air. Even though unit 4 was empty with
no fuel in its core, its upper building also exploded on the 4th day. Hydrogen had flowed
from unit 3 via a connecting pipe. Unit 2 may have had a small explosion inside its lower
suppression chamber with concerns it punctured the containment. But its upper level did not
explode. By chance a side panel happened to be open which allowed the hydrogen to escape.
The damage from the explosions was extensive but crucially the Japanese reactors remained
intact and none of the highly radioactive reactor fuel got out. The Fallout came from
the radioactive aerosols released and from contaminated groundwater that flowed into the
Pacific Ocean which mostly diluted to safe levels. Chernobyl ejected about 10 times more radiation
than Fukushima as shown on these Maps which are at the same scale. Roughly 340 000 people were
uprooted from areas contaminated by Chernobyl. Of those only a small number have returned. The power
plant city of Pripyat with 50 000 inhabitants was turned into a ghost town by the disaster.
Fukushima has about 35 000 people still displaced.
At the peak approximately 170 000 people were evacuated.
The Chernobyl exclusion zone is 7 times larger.
Chernobyl was the result of a flawed reactor design and operator error. The RBMK reactor
type was perilously unstable at low power and at risk of an unstoppable catastrophic reactivity runaway.
During a badly managed safety test the operators removed almost all control rods at the
worst moment and the reactor rapidly disassembled. The Fukushima meltdowns happened when all power
systems failed from flooding. The most powerful Japanese earthquake on record hit the plant
and the reactor shut down automatically like clockwork. The plant survived the earthquake but
not the tsunami 50 minutes later. Sea water filled the basement. The plant suffered total power loss
including its multiple diesel generators and battery backups. The power company did
not ensure the vital backup power was safeguarded from flooding. The Chernobyl core was on fire for
days spewing highly radioactive reactor particles directly into the atmosphere far and wide wherever
the wind blew. Half a million people were involved in the epic radiation cleanup, many of whom were
exposed to very dangerous levels particularly on the roofs. It was an out of control radioactive
nightmare for 7 months until the wreckage was enclosed with a cover called the sarcophagus.
30 Years after the explosion a more permanent and secure arch encloses the radiation.
Fukushima also installed protective enclosures over its damaged units. They
have equipment for removing the deadly mess and for dismantling the reactors.
Fukushima now has a major headache with more than 1 000 tanks of contaminated water on site
from the cleanup efforts. There are plans to release decontaminated water into the Pacific.
This is routinely done at nuclear plants worldwide however the public and fishermen don't believe the
government is telling the truth about the danger. To contain the flow of contaminated groundwater
into the Pacific an underground ice wall was constructed that surrounded the damaged reactors.
At Chernobyl 30 died within 3 months from acute radiation sickness. Zero died at Fukushima.
Cancer deaths from the Chernobyl radiation are estimated to be a few thousand. The number of deaths from
radiation-related cancer is highly contested and controversial but there is simply no way
to know for sure. The Japanese strictly limited the radiation exposure to people so it's unlikely
anyone will die from Fukushima related cancer. So what are the takeaways? Both accidents were
preventable and are sobering examples of when politics and culture hobble safety. Chernobyl
happened because of the Soviet Union's inability to function in a common sense and safety conscious manner.
The reactor's catastrophic danger at low power was swept under the rug and kept secret
from control staff who otherwise would have avoided the deadly actions of that evening.
It was unacceptable that the Fukushima emergency power was vulnerable to flooding in a tsunami zone.
If the diesel generators and switches had been located intelligently the disaster
would not have happened. Official investigators in Japan concluded that collusion and nepotism
led to capture of the nuclear regulators and lax oversight. They further concluded that ingrained
conventions in Japanese culture namely, reflexive obedience, the reluctance the question authority
and a fear of sending bad news upwards got in the way of following International best
practices and standards. Decision paralysis while the crisis unfolded made the accident
more serious than it could have been. So which was worse? Even though these are the only 2 accidents
to score the maximum level 7 on the nuclear event scale, Chernobyl was much more deadly,
much more destructive, the call was exposed and they lost control of the reactor fuel. 50 Tons
of incredibly radioactive uranium was scattered about. The Chernobyl core was wide open while
at Fukushima the containment was intact and this alone makes Chernobyl incomparably worse.
There is a persistent myth that Fukushima polluted the Pacific but this was not based in fact.
There was sneaky misuse of this map which had nothing to do with radiation and in reality
indicated the tsunami wave height. Except for the immediate vicinity of the plant the radiation in
the ocean diluted into just a fraction of naturally occurring levels. Fukushima did
not turn the Pacific radioactive. Fair to say on pretty much all metrics Chernobyl was worse and
it wasn't even close. In spite of fight these disasters it is striking to see the appetite
for nuclear swing positive so fast in 2022. With a shock Europe is suddenly at the mercy
of Russian gas and coal use is surging again to record levels. A renewed review is underway
into the clear benefits nuclear offers. More than ever we need smart people who believe in science,
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RBMK reactor or my other content. Thank you for watching and I will see you in my next video.