While the name Chernobyl is
familiar enough to most people in the modern era, few
grasp the true extent of the disaster
that happened there. The Chernobyl meltdown is
often casually summarized as a horrible accident. But putting the sequence of
events that led to the disaster into context reveals the cause
to be a series of compounding mistakes that started
with the design and construction of the
plant and continued on well into the disaster's cleanup. Today, we're going
to take a look at everything that had to go
wrong for Chernobyl to happen. But before we get started, be
sure to subscribe to the Weird History channel and let us
know in the comments below what other disasters you
would like to hear about. OK, zip up your radiation
suit because we're going back to Pripyat. [MUSIC PLAYING] The truth is the Chernobyl
reactor was badly designed. And its operators were
never informed of that fact. They had no idea the
experiment they were conducting on April 26, 1986,
could bring the reactor to an explosive condition. However, even given that, the
experiment which ultimately caused the incident was, by all
accounts, both poorly planned and poorly executed. Previously-established
safety protocols were disregarded in the name
of expediency, something that was endemic of an
overall lack of safety culture at the plant. After an investigation, the
International Atomic Energy Agency concluded
that when assessed in terms of the concept
of safety culture, the project was severely
lacking not only at the operational
stage but at every stage in the lifetime of the plant. Safety-related
decisions were found to be questionable in all
phases, including design, engineering, construction,
equipment manufacture, as well as administration
and regulation. The experiment on
Chernobyl's unit 4 reactor was intended to determine
whether its emergency systems could operate
under inertial force in the wake of a power outage. However, just before the
experiment was conducted, the emergency core cooling
system was disconnected. It would remain so throughout
the duration of the test. The detonations that
would later rock the plant were ultimately caused
by other mistakes. But the absence of
the cooling system further complicated
the situation and underscored the plant's
general lack of interest in safety. While the initial guidelines
for the experiment called for the reactor
to be stabilized at a power level of
approximately 1,000 megawatts, human error caused the level
to sink to a mere 30 megawatts. This caused the reaction within
the plant to destabilize. Operators did their best to
compensate for the low power levels. But they were only able to get
back up to about 200 megawatts. At that level,
while it was stable, it was still
extremely dangerous. Unfortunately for
everyone involved, the steps the operators took
to raise the power levels would lead directly
to the accident that would consume the plant. The Chernobyl experiment
continued into the night of April 25, 1986. Operators were becoming
increasingly frustrated at the inability
to raise the power levels inside the reactor. To compensate, they began
to remove control rods. The safety protocol called
for a minimum of 15 rods. But the operators kept removing
them until they were down to just eight. As a result, the reactor
crossed the minimum operating reactivity margin,
which is not good. This created what is known as
a positive void coefficient, which reactors of that type
were prone to developing and which is also not good. Ultimately, what
that all means is that the reactor was left
vulnerable to a potential power surge, creating a greater risk
of complete nuclear meltdown, which is the
ultimate in not good. The experiment
procedures require that the turbine engines feeding
the reactor with cooled water be shut down. This alone wouldn't
have been so bad. But after struggling to increase
the power in the reactor, the operators also reduced
the flow of feed water. These two factors
combined caused the temperature within
the reactor to increase and along with it
the amount of steam. While there are many
competing theories as to what led directly to this
first detonation, many believe it was
this excess of steam. Whatever the case, the
steam at the very minimum exacerbated the
instability of the reactor. Operators were struggling to
increase the power to the unit 4 reactor when they
were suddenly hit by the exact opposite problem-- a massive power surge. Although there are
several theories, no one knows exactly
why the surge occurred. But whatever the
cause, the surge rupture the reactor's fuel cells
and raised the temperatures to catastrophic levels. This in turn generated
even more steam. The increasing volume
of steam further increase the pressure,
which eventually ruptured the fuel elements and
depressurized the reactor's cooling circuit. Once this happened,
the detonations that would rock the plant
were all but assured. As the power levels
in the reactor peaked, the operators hurried to
insert more control rods. But it was too late. Even worse, this attempt
to regain control may have been a fatal mistake. The control rods
used at Chernobyl contained graphite displacers. And long story short, there
are compelling reasons to believe that this graphite
triggered a nuclear reaction with the rupturing fuel cells. This theory explains
the severity of the very first
detonation, which had so much force behind
it it literally blew the two-meter thick lid made
of concrete and steel right off the reactor. A second explosion likely
caused by a buildup of hydrogen due to all the steam
reacting with zirconium happened only seconds later. While the initial explosion had
blown the lid off the reactor, the second one blew it sky high. Along with it, large quantities
of fuel and moderator were also ejected. At least one person whose
body was never recovered was killed instantly. A second died in the hospital
just a few hours later. As if all that
wasn't bad enough, the explosions left the
core of the reactor exposed. Radiation began to seep
through Chernobyl and then to the whole world. Given the intensity
of the detonations, you'd think alarms
would be sounding and the whole plant would
be springing into action. But it wasn't like that. In fact, the immediate response
was surprisingly relaxed. Work on the other reactors
continued as usual. Even the fire crews who
arrived to fight the blazes didn't bother to
wear protective gear. Two workers lost their lives
in the immediate aftermath. And 28 other casualties,
mostly first responders who soaked up enormous
amounts of radiation, were directly attributed
to the meltdown. Over 100 people
were hospitalized with acute radiation syndrome. And a few dozen others died
in the weeks and months that followed. About two miles or three
kilometers away from Chernobyl was the city of Pripyat. Citizens there
were told nothing. But they couldn't help
but notice the officers walking their
streets in gas masks. Rumors spread fast. Radiation was spewing
out of Chernobyl. But local officials
intent on sticking to the party line of
covering up the accident made no immediate effort
to evacuate the town. The evacuation order
didn't come until 36 hours after the initial detonation. Residents were given one
hour to pack their things and leave for what they were
told would be just a few days. In truth, there would
never be allowed to return to their homes. And thanks to the
delays, they had absorbed an unknown amount of radiation. As if the initial response
to the Chernobyl meltdown wasn't bad enough, the cleanup
was a messy, dangerous, tedious ordeal. Ultimately, it would take
more than a half a year to contain the situation. But finally, a concrete
and steel casing was poured over the reactor
in November of 1986. There's a lot of
blame to go around for how Chernobyl was handled. But at least some
has to be assigned to Mikhail Gorbachev and
the Soviet government who all let their
reactions be affected by political considerations. The government was collapsing. And no one wanted to
acknowledge the disaster. They wouldn't even admit
that the disaster occurred until more than
a day had passed. And it would still be longer
until they informed the public. The first responders
who were brought in to contain the
incident probably knew they were headed into danger. However, there's
no way they could have known that incompetent
decision making would result in unnecessary exposure
to mind-boggling amounts of radiation. At first, officials
tried using robots to clear the burning graphite
from the roof of the reactor. But they malfunctioned. Another plan tried
using helicopters to fly over the nuclear
flames and pour sand on them. But not only didn't it work,
it exposed the helicopter crews to irradiated updrafts. All this meant
that actual humans would have to climb on
top of the reactor, which still had its core uncovered
for extended periods. Officials attempted to
contain the further release of radiation into the
atmosphere by burying the irradiated topsoil
and vegetation. However, this plan may have
had an unintended but highly dangerous consequence. Namely, it may have
kept the radiation out of the atmosphere. But it redirected it
into the groundwater. According to some
accounts, the cleanup ignored protocols that mandated
geological surveys designed to avoid precisely
such a situation. Instead, the crews dug until
they hit water and then pushed the topsoil right in. This would have spread
the radiation even further beyond the exclusion zone. The area surrounding
Chernobyl was rife with valuable resources. And the Soviet government
wasn't eager to see so much go to waste. Officials developed
questionable standards for quantifying which
food products were safe and which were contaminated. As a result, irradiated items
ended up on store shelves. Large quantities of
contaminated meat were even kept in
cold storage in hopes that they would become
edible again someday. The Soviet government didn't
seem to have learned a lesson. They were displaying more of the
flagrant disregard for safety that caused the meltdown
in the first place. Mikhail Gorbachev is
known to have found out about the meltdown only
hours after it occurred. But he wasn't eager
to spread the news. Despite increasing attention
from scientific observers worldwide, his government pushed
ahead as if nothing was wrong. Radiation levels in Ukraine
and around the world were increasing. Yet the central party still held
a big outdoor event in Kharkiv for May Day. Their recklessness and
arrogance cost untold lives. While only 30 casualties
are officially attributed to Chernobyl, the
World Health Organization believes that
thousands of others have been killed over time from
related cancers and illnesses. In trying to keep a
lid on the situation, the Soviet government
prevented their own citizens from protecting themselves. The true cost of the coverup
remains impossible to know. So what do you think? Could something like
the Chernobyl disaster happen again? Let us know in the
comments below. And while you're at it, check
out some of these other videos from our Weird History.
