The accident at the Chernobyl nuclear power station was graphic evidence, not only of how obsolete our technology was, but also of the failure of the old system.

At the same time, and such is the irony of history, it severely affected our reforms by literally knocking the country of its tracks.

Mikhail Gorbachev.

Ah, pryvit everyone!

Welcome to today's episode of History In A Nutshell.

It's probably best for me to wear a radiation suit in this edition, for today we are traveling back in time to 1986 Ukraine.

The year 2026 marks the 40th anniversary of the disaster at the Chernobyl Nuclear Power Station.

To this day, the accident at Chernobyl is the worst and most expensive nuclear disaster in human history and folks living in Ukraine, Russia and Belarus are still dealing with the after effects all these years later.

So what caused this accident, and how has the disaster affected the economies, environments and health of the people in the region?

Follow along with me as I break down the history and long lasting legacy of the Chernobyl disaster.

But before we can even begin to assess the accident itself, allow me to set the stage.

Our story begins here at the Vladimir I. Lenin Power Station, named after the founding leader of the Soviet Union.

Throughout the 1970s and early 1980s, the Soviet Union engaged in a widespread reactor building program, the V.I.

Lenin plant being one of these many installations.

Soviet scientist Mikhail Styrikovich once remarked: Nuclear power plants are like stars that shine all day long.

We shall saw them all over the land.

They are perfectly safe!

Nuclear power seemed cheaper than more traditional oil or coal plants.

Construction of the plant began in 1972, with the commissioning process taking place between 1978 and 1984.

This power station was located about two miles away from the town of Pripyat and ten miles from the Ukraine-Belarus border.

Chernobyl Town, the closest major town to the plant was located about ten miles to the southeast.

The city of Pripyat was purpose-built to house the V.I.

Lenin Plant's workers and their families.

Around 50,000 people used to live there.

It is a ghost town now, but back in the early 1980s, it was a thriving town where Soviet citizens went about their daily lives.

The V.I.

Lenin Plant housed 4 RBMK-1000 nuclear reactors, with two more under construction in 1986.

RBMK stands for "Reactor Bolshoy Moshchnosti Kanalniy" which translates to "High Power Channel Reactor".

Each of these reactors could generate 1000 Megawatts of power.

One Megawatt equals 1,000,000 watts, so 1000 Megawatts equals 1 billion watts!

Before the accident, the V.I.

Lenin Plant provided roughly 10% of Ukraine's electricity.

RBMK reactors saw widespread use throughout the Soviet Union due to their economic efficiency, ease of construction,and high power output.

However, RBMK reactors had gained a reputation for their flaws.

Primarily, RBMKs had no containment structures, leaked high amounts of radiation, unstable at low power levels, unstable graphite-tipped control rods, and dangerously high positive coefficients.

If you're scratching your head wondering what all that means, don't worry, I'll elaborate later when we get to the accident itself.

Some Soviet physicists like Grigori Medvedev wrote on the dangers of these RBMK reactors, but due to the political climate in the Soviet Union, he was largely disregarded.

Publishers refused to publish his articles, and Soviet politicians hand-waved away Medvedev's findings.

The Soviet Union was living under what was known as the "Period of Stagnation" which began under the leadership of Leonid Brezhnev in the 1960s.

The Soviet bureaucracy was largely unaware of the realities of life and protected from criticism through a combination of secret police forces, propaganda, and an obsession with censorship and national interests.

Citizens were taught to have complete faith and trust in the Soviet government.

It was the will of the authoritarian Communist Party above all else.

Political dissidents could face public ridicule, loss of jobs, exile, or be sent to gulags.

Due to this atmosphere of controlled information and compliance, few individuals dared question the government's assurances that Soviet reactors were totally safe.

The accident at Chernobyl was not the Soviet Union's first nuclear disaster.

Prior incidents did happen, but news of these accidents was suppressed due to the government's systematic censorship.

One such incident occurred in September 1957.

There was an explosion of nuclear waste at the nuclear fuel reprocessing plant at Chelyabinsk-65.

This explosion spread deadly radiation over an area of approximately 9,000 square miles.

That's about the size of the state of New Hampshire.

To keep this incident a secret, Soviet officials not only evacuated and closed Chelyabinsk, but the town was scrubbed off of maps.

That incident in particular, only became public knowledge about 40 years later.

Accidents in the Soviet Union caused by flawed reactors, machine faults, and poor training all went unreported to other nuclear workers.

No one had the opportunity to learn from these prior incidents, and an atmosphere of complacency was allowed to develop in the Soviet nuclear industry.

Circling back to Dr.

Medvedev, he tried to warn people that an accident like what eventually happened at Chernobyl was inevitable.

And on April 26th, 1986, his warnings became reality.

In the early morning hours of April 26, Deputy Chief Engineer Anatoly Dyatlov and his team were conducting a long overdue safety test on reactor #4.

The purpose of this test was to determine if the turbines and generators could provide energy long enough to run the reactor's coolant pumps in the event of a total power outage.

The steam turbine generator needed to continue running between 45 and 60 seconds before the emergency diesel generator started up.

The reactor's coolant systems were shut off to simulate this power failure.

This test was originally supposed to have been carried out by the afternoon shift.

However, party officials in Kyiv ordered them to delay the test so as to not possibly interfere with the working day.

Only the afternoon shift workers were properly briefed on this test.

The night shift workers who actually carried out the test were not briefed at all!

Neither Shift Foreman Aleksander Akimov nor Senior Reactor Engineer Leonid Toptunov had ever conducted a test like this before.

At full power, the reactor generated about 3200MW thermal, which is equal to 1000MW electric.

In order to conduct the test, the power needed to be reduced down to 30%.

No one in the control room really understood the danger of reducing the power down that low for a flaw in the RBMK reactor's design made it extremely unstable at low power levels.

Akimov and Toptunov felt the power had already been reduced down too low to conduct the test, but Dyatlov insisted they continue.

As power was decreased, the reactor started behaving unpredictably.

Dyatlov's response to the bizarre readings on the instrument panel was to rant at his staff for their supposed incompetence.

At 12:30 A.M., power dropped from 500MW down to an unexpected 30MW.

Reactor operators then withdrew a number of the control rods in order to bring the reactor back to a safer operational level.

Toptunov pleaded with Dyatlov to stop the test and shut down the reactor as safety protocols outlined but Dyatlov declared that Toptunov do as he's told or else face replacement by another worker.

Dyatlov had Akimov and Toptunov remove all but 8 of the control rods when safety protocols called for a minimum of 15 rods.

The power did go back up a bit, and the pumps were switched on to increase the flow of cooling water into the core but doing this reduced water levels in other parts of the reactor, causing it to boil dry, not unlike an empty tea kettle.

The test proceeded.

In their attempts to get the reactor to settle at a lower level the control room staff made the reactor extremely unstable.

The cooling water at the core turned into superheated steam.

Steam from the reactor to the turbine was shut off.

The turbine continued to rotate under its huge momentum, but as it slowed, it generated less electricity, causing a decrease in the flow of vital cooling water to the reactor core.

The reactor was overheating now as steam inside the core increased uncontrollably.

At 1:23:40 A.M., Akimov noticed a massive power spike and pressed the AZ-5 emergency scram button which sent all those graphite-tipped control rods down into the core to shut down the reactor.

Doing this caused that positive void coefficient mentioned earlier.

Pressing this panic button was meant to shut down the reactor, but instead it increased reactivity, not reduced.

As the rods moved down into the core, they displaced the neutron absorbing water at the bottom of the reactor, causing steam bubbles to form and a rapid power surge.

When these control rods descended, reactor power increased more than 100 times its safety limit!

The increasing steam pressure inside the core caused these control rods to become jammed.

20 seconds later, at 1:24 A.M., the first explosion happened.

A massive steam explosion blew off the reactor's heavy steel cover plates exposing the reactor core.

This caused the second, much bigger explosion.

The roof to reactor #4 was obliterated, and the explosion spewed radioactive materials up into the air and around the plant side.

Uranium fuel and bits of highly radioactive graphite now lay exposed, and the asphalt roof was now ablaze.

Some witnesses in Pripyat noticed a bright blue-white light shoot into the sky from the reactor, followed by a fire.

Dyatlov and the rest of the men in the control room, however, had no clue that their reactor was no more.

The most dangerous radioactive isotopes disseminated by the accident were Iodine-131, Cesium-137, and Strontium-90.

The plant workers, as well as the firefighters and emergency responders who rushed to the scene were exposed to this deadly radiation.

They immediately began feeling the effects of Acute Radiation Syndrome: a feeling of burning inside and out.

Burning eyes and throats.

A metallic taste in their mouths, and severe nausea.

Sieverts is the standard unit for measuring the biological effect of radiation on the human body.

To give you an idea of exactly how much radiation they were exposed to, let's do a quick comparison.

A typical C.T.

scan at a hospital is between 1 and 10 milliSieverts of radiation, which is pretty harmless.

The first responders and plant workers at Chernobyl, however, received fatal doses of radiation ranging from 700 to 13,400 milliSieverts, or between 7 and 13.4 Sieverts.

The firefighters battled radiation and toxic smoke to put out the roof fire, and by daybreak on April 26th, the fire was out.

These men showed extraordinary bravery to put those deadly fires out.

Over the next few months, 28 of them would die agonizing deaths from radiation poisoning.

The fire inside the core, while contained, would continue to burn for another 9 days.

Later in the morning of April 26th, Plant Director Victor Bryukhanov and Chief Engineer Nikolai Fomin met to assess the damage but out of fear of reprisals from the Soviet government the message they sent to Moscow was horribly inaccurate.

They said the reactor is intact.

Only one person died, and the situation is within normal limits.

That afternoon, Valery Legasov, the First Deputy Chief Director of the Kurchatov Institute of Atomic Energy arrived at the plant.

Legasov had been appointed to the Soviet Government Commission, and he quickly set to work investigating the cause of the accident and overseeing cleanup procedures For about 2 weeks after the explosion, helicopters dumped around 5,000 tons of sand, clay, boron and lead to put out the fire inside the core.

Deep beneath the ruined reactor #4, all that nuclear fuel, sand, clay and boron all congealed together into a nasty concoction called "Corium".

Nicknamed "The Elephant's Foot" this highly radioactive glob to this day cannot be accessed by the general public.

This thing will continue giving off deadly radiation for at least another 300 years!

Standing next to this thing for mere minutes could lead to a very unpleasant death.

Mere days after the explosion, it was discovered that the molten nuclear fuel was burning through the concrete flooring beneath the reactor.

There was still a bunch of water pooled in the basement below: about 20 million liters from when the firefighters put out the roof fire days before.

If that molten fuel reached the water below, the Chernobyl disaster would have gone from bad to worse.

A massive radioactive steam explosion between an estimated 3-5 megatons would have destroyed the entire plant, potentially causing a nuclear fallout which could have affected the entire planet.

Someone needed to go down into the basement beneath the reactor and drain that water using specific valves.

On May 4th, 1986, 3 men: Mechanical Engineer Oleksiy Ananenko, Senior Engineer Valeriy Bespalov, and Shift Supervisor Boris Baranov step forward to do this task.

They were advised that if they did not survive, their families would be taken care of.

Everyone watched as those men donned wetsuits and made the trek into the dark basement below.

Miraculously, the men found the valves, drained the water and emerged to a hearty job well done by fellow comrades.

Those 3 men are remembered today as "The Suicide Squad".

Thankfully, all 3 men lived long, happy lives after that.

At Legasov's insistence, the town of Pripyat was evacuated pemanently.

From 1986-1989, between 600,000 and 800,000 men of various backgrounds known as "Liquidators" were brought into the exclusion zones to decontaminate the plant, clean up the area, and construct the concrete "Sarcophagus" around the remains of reactor #4.

Many of these volunteer workers did their duties, despite not being aware of how much deadly radiation they were exposed to.

How did the Soviet government respond to the disaster?

Officially, "RBMK reactors don't explode".

Soviet officials attempted to downplay and cover up news of the nuclear accident, but they couldn't hide it for long.

High altitude radiation readings were detected as far west as Wales and Sweden, and as far east as Japan and the west coast of the United States.

American spy satellites also captured photos of the destroyed reactor #4.

Other countries knew something had happened in Ukraine, but the Soviet government continued to deny.

Later that year in August 1986 Legasov presented his report to the International Atomic Energy Agency in Vienna, Austria.

His investigation concluded the main causes for the destruction of reactor #4 were design flaws in the RBMK reactor, negligence of safety protocols, and operator errors.

Later accounts from Legasov's private tape recordings revealed his frustrations with Soviet secrecy and bureaucratic blindness to safety issues.

In July 1987, Viktor Bryukhanov, Nikolai Fomin and Anatoly Dyatlov were tried and found guilty of gross violations of safety regulations and sentenced to 10 years in labor camps.

The 3 men may have acted unwisely, but they were molded by the system which produced them.

None of them served their full sentences.

The Chernobyl disaster is the worst and most expensive nuclear disaster in history; the effects of which are still felt in Eastern Europe today.

Chernobyl is widely accepted to be one of the main causes for the fall of the Soviet Union.

The accident accelerated Mikhail Gorbachev's policy called Glasnost: a series of reforms encouraging more accountability and transparency, exposing decades of government corruption and inefficiencies.

The Soviet government's attempts to cover up the disaster at Chernobyl shattered the public's trust in the communist system, severely damaging its reputation.

Instead of reforming the old system, citizens preferred to create a new one.

Five years after Chernobyl, the Soviet Union collapsed.

The Chernobyl accident had disastrous effects on the economies of Ukraine, Belarus, and Russia, in addition to other surrounding European nations.

Billions of rubles were spent on initial cleanup costs, and billions more were spent on healthcare, lost agricultural farmlands, and resettlement costs for those who lost their homes.

While the approximately 4,200 square kilometer "Exclusion Zone" remains restricted, surrounding farmlands in northern Ukraine have been deemed safe for a return to agricultural activity.

Growing crops such as wheat, sunflowers and rapeseed for oil, the final casualty figure for the disaster is almost impossible to estimate.

The accident directly affected between 5-7 million citizens of the former USSR, including the 600,000+ "Liquidators".

In the years immediately following the disaster, an estimated 2,000+ children became ill with thyroid cancer, with a slight increase in cases of leukemia.

There were growing fears in the scientific community that the aging original concrete "Sarcophagus" housing reactor #4's remains would fall apart, especially in the event of an earthquake.

A new 300ft arch-shaped steel containment structure was built and slid into place in 2016.

The power plant was shut down between 1991 and 2000, and is currently undergoing decommissioning, which is expected to last until at least the year 2065.

The remaining RBMK reactors throughout former USSR countries underwent major safety overhauls, and a dozen RBMKs have since been operating for well over 30 years without any further serious incidents.

There are several positive notes to share: the "Exclusion Zone" with its lack of human activity has unintentionally become a thriving wildlife sanctuary.

Many animals, including bears, wolves, bison, birds and even dogs descended from the abandoned pets in Pripyat now call the "Exclusion Zone" home.

Those former residential areas have transformed into dense forests and wetlands.

The wildlife living in the "Exclusion Zone" has been studied by scientists since the accident To measure how nature has adapted to long-term exposure to low radiation levels.

The disaster also highlighted the bravery and heroism of those who came together to face this crisis.

The plant workers, first responders, Liquidators, miners, the Suicide Squad, healthcare workers, as well as Valery Legasov himself.

Were it not for their combined efforts, the accident could have turned out much worse.

Several monuments, including the "Monument to Those Who Saved the World" are dedicated in honor of Chernobyl's firefighters and Liquidators For the nuclear industry itself, the accident at Chernobyl spurned a massive global safety culture revolution.

After Chernobyl, safety reviews and international peer reviews became standard practice.

To prevent the dangers of secrecy, the global nuclear industry adopted higher standards of information sharing and transparency.

In May 1989, the World Association of Nuclear Operators was founded to promote a global, nonpolitical, collaborative effort to improve nuclear safety and reliability.

"Chernobyl made it clear that an event at one plant impacted every plant, and that nuclear safety was everyone's business."