Original subtitles

DR CHERNYSHOVA: The reason why Chernobyl seems such a dire warning

to so many people around the world

is the nuclear disaster that happened there

affected the entire planet.

I remember the first time going into the site itself.

It's a sinister place

because you can't help remembering what happened there

and how it had affected hundreds of thousands of people's lives.

NARRATOR: Two miles from Chernobyl, the city of Pripyat,

once home to 50,000 people,

lies in ruins.

Vegetation is taking over,

there are trees that are growing

into the upper floors of the tower blocks.

A 1,000-mile exclusion zone

has restricted access to the site for the past 36 years.

(SIRENS WAILING)

But that all changes on 24 February 2022...

..when Russia invades Ukraine

in a bid to take back the former Soviet Republic.

An early strategic target

is the Chernobyl nuclear power plant.

Russia was moving tanks through the zone

and that raised radioactive dust.

Russia is really weaponising nuclear power plants

in this war on Ukraine.

The story of Chernobyl is decades in the making.

It began when the emerging Soviet Union's nuclear power programme

threatened the world.

(SPEAKS FOREIGN LANGUAGE)

A Soviet dream that became a nightmare.

A disaster officials tried to cover up...

..as a brave few battled

to stop radiation spreading across the globe.

Using top-secret Soviet documents...

(CHEERING)

..and hearing from those who risked everything.

This is the story

of one of the world's worst nuclear accidents.

Early morning.

The Chernobyl nuclear power plant

gets ready to carry out a safety test

on Reactor Number Four.

Every nuclear power station has to undergo a series of tests,

and one of the safety tests that it needed

to prove to continue to operate

was to test what would happen to the coolant system

if there was a power cut.

Engineers planned to switch off four of the pumps

to test their backup systems.

If there was a power cut

and the emergency generators didn't kick in,

there would be a real problem.

The job was extremely difficult and complex

and demanded a lot of concentration, a lot of experience.

It was kind of a routine test,

but it was conducted in such a way

that that routine test turned into a terrible accident.

The Chernobyl disaster can be traced back to the 1960s

when Ukraine was part of the USSR,

and harnessing nuclear power was a major Soviet ambition.

ANNOUNCER: A multi-stage rocket

took off from a launching site in Russia.

The mid-20th century was the height of the Cold War.

Rival superpowers, the Soviet Union and USA,

are vying for technological...

..and military supremacy.

The USSR is determined to lead the world

in harnessing nuclear power,

and it pours vast resources into nuclear research.

Nuclear power was enormously important to the Soviet Union

and scientists were these heroes of the Soviet Union.

And nuclear research was the flagship

of what Soviet science could offer.

Soviet leadership plans to build a vast nuclear power plant.

One which would dwarf any the world has ever seen.

(CHHEERING)

The reason why they wanted to build such a large reactor,

the biggest in the world, they hoped,

was national pride.

The Soviet Union at the time was engaged in a,

not just an arms race with the United States,

but a cultural, political competition

prove themselves that their system of government and life was best.

The new plant is to be built in the Ukrainian wilderness,

60 miles north of the capital, Kyiv.

It's named after a nearby town, Chernobyl.

Ukraine enjoyed a special status in the Soviet Union.

It was very important economically.

It also contained very important industries

on its territory, coal mining industries of course,

and many others.

A very important member of the Union,

for political, strategic military reasons,

economic reasons especially.

It's on the borderland, facing to the West,

it's also a showcase of Soviet, modernity.

In the winter of 1970,

the man chosen to build and run Chernobyl

arrives in northern Ukraine.

Despite having never worked with nuclear power,

34-year-old Viktor Brukhanov

will be Chernobyl's first director.

Viktor Brukhanov was a young man when he was picked,

surprisingly, to take on the Chernobyl project.

He was an electrical engineer,

he'd worked in a couple of power plants

across the Soviet Union,

but this was his first nuclear power job.

Engineer Nikolai Steinberg worked on the project with Brukhanov.

(SPEAKS FOREIGN LANGUAGE)

His main deficiency

was that he was never trained as a nuclear engineer.

The real reason he was picked

was because the authorities thought he was a man

who'd be able to master a very, very complex, difficult task.

Construction of the huge power plant gets underway in early spring, 1970.

The first of six planned reactors will take seven years to build.

As the power plant grows,

so does the city built to house its workers.

Pripyat is one of nine atomgrads,

or atomic cities in the USSR.

Each one is built from scratch,

for workers of the nuclear industry and their families.

Pripyat was a city whose reason for existence was Chernobyl,

and in many ways, it was a model Soviet city.

It was what the socialist city was supposed to be like.

The apartment buildings were very well made.

The shops were stocked,

which was quite unusual in Soviet society,

especially in the '70s.

(SPEAKS FOREIGN LANGAUGE)

Chernobyl's 5,000 workers and their families

lived just two miles from the power plant.

Seven years after work began,

Chernobyl's reactor number one is finally ready to be switched on.

Plant Director, Viktor Brukhanov,

is now at the helm of Chernobyl's first reactor,

and is charged with building five more.

But it won't be long

before Chernobyl suffers its first accident.

And the authorities are quick to cover it up.

Three nuclear reactors are now fully operational at Chernobyl.

The completion of a fourth

will make this the largest nuclear power station in the Soviet Union.

The Ukrainian city of Pripyat,

built to house Chernobyl's workers, is also flourishing.

In 12 years, it's grown from a wasteland

into a city of 50,000 people.

Although they live in a Soviet paradise,

the residents of Pripyat are unaware of the danger they're in.

The new Chernobyl power plant is already riddled with problems.

But it would take until 2020,

when the Ukrainian government

released thousands of top secret documents,

that Chernobyl's early safety problems were made public.

One of them exposes how unsafe

the power plant is becoming.

The report is dated from 5 January 1983,

and according to this report,

between January 1978 to December 1982,

the Chernobyl nuclear power station

experienced 27 accidents and 87 equipment failures,

including five accidents and 16 failures

in just 12 months of 1982.

One of the most serious accidents happens in late summer.

Chernobyl's number one reactor undergoes a routine safety test.

Nikolai Steinberg, Head of Turbines,

is in his office in the third reactor building.

Outside Nikolai's office

runs a ventilation pipe connected to Reactor One.

The steam is part of a major radiation leak.

Reactor One is shut down.

Nikolai waits for a briefing on the incident from his bosses.

The cause of the accident is kept secret

from Nikolai and his colleagues.

One reason for the secrecy

is down to the presence of the KGB,

the Soviet Union's secret police.

They're a constant presence at Chernobyl.

Well, the KGB's job would be partly to investigate

whether this was an act of sabotage,

or whether there was someone, who was simply negligent,

but also part of their job was to contain rumours,

and to prevent the spread of panic.

The KGB investigation is more concerned with quashing rumours

than uncovering why the accident happened.

They do talk about the presence of distorted rumours

that spread by residents of the city of Pripyat,

and there's this kind of nightmare scenario for the Soviet authorities

that rumours will spread.

None of this was reported in the press.

After the accident,

radiation is detected nine miles from the plant.

In some areas,

the levels are hundreds of times higher than normal,

but the residents of the nearby city of Pripyat

are kept in the dark.

Despite the accident, Chernobyl continues to grow.

It's now 13 years

since work began on the plant.

Managers are under orders to complete the fourth reactor

by the end of the year.

Engineers like Vladimir Kagan are feeling the pressure.

They were incentivised

to get jobs done by a particular time,

and this meant bonuses, this meant certain perks.

The people who were able to meet those deadlines,

they were rewarded and that was part of the game.

By the end of December, Reactor Four is near completion.

Everything had to be finished by December.

That's when the bonuses were handed out.

But before it can become operational,

the reactor must undergo a critical safety test.

The turbine test that was the last remaining test

that was due to be done on the unit four reactor,

hadn't been done by December.

Carrying out the test now will mean a delay.

The reactor might not be ready by the December deadline.

The decision on whether or not to go ahead with the test

falls to Plant Director, Viktor Brukhanov.

So, Brukhanov said, "OK, we'll sign it off

"and then we'll come back and do it at a later date."

Despite the safety test not being carried out,

Brukhanov allows the reactor to enter service.

He was someone who was taking risks, he believed calculated risks.

He lacked really deep understanding what he was running.

With Reactor Four online,

Brukhanov is now in charge

of the Soviet Union's biggest nuclear power plant.

Spring 1985.

Events in Moscow are about to put nuclear energy

at the forefront of Soviet politics.

The USSR has a new leader.

Mikhail Gorbachev's arrival

heralded an era of transformation in the Soviet Union.

He was seen as a new, different type of leader.

He had a meeting with Margaret Thatcher

in December 1984.

They famously get on very well together.

There's a feeling, I think,

that things are beginning to change inside the Soviet Union.

(CHEERING)

He understood that the Soviet Union and Soviet economy

especially, were in need of reforms,

and he was willing to undertake that project

of reforming the Soviet Union to save it.

One of Gorbachev's first tasks

is to announce a plan to revive the economy,

made to an audience of 5,000 high-ranking party members.

Gorbachev presided over the party congress

and that congress adopted a resolution

to double the number of the nuclear reactors

that they would build in the next five-year plan,

so, nuclear energy was supposed to be the solution,

or at least part of the solution,

of how to drag the Soviet economy out of that stagnation.

In the audience is Chernobyl's Director,

Viktor Brukhanov.

He will be held personally responsible

for helping meet Gorbachev's ambitious goals.

So, the pressure on the management

was actually now becoming even stronger,

and the burden on their shoulders was even heavier.

Chernobyl's four reactors, known as RBMK reactors,

are of a type unique to the Soviet Union.

The RBMK reactor was really advanced for its time,

much more so than western reactors,

and this was because it could put out

the most amount of power for a reactor of its size.

This also meant that it was really cost-effective,

which is why they were able to build so many across the Soviet Union.

In total, 17 RBMK reactors are built.

All produce energy in the same way.

Effectively, the nuclear reactor is like a kettle.

It's generating steam by splitting uranium atoms to generate the heat.

The heat then is used to heat water,

the water is then turned into steam,

which turns turbines to generate electricity.

Reactor Number Four has been running for two years,

when the long-delayed safety test is finally scheduled to take place.

The test will be overseen by Deputy Chief Engineer,

Anatoly Dyatlov.

Dyatlov was one of the few people at the top

who was trained as a nuclear engineer.

He had quite an abrasive personality.

Dyatlov was very often feared,

and he was using a very harsh language

to deal with his subordinates.

The test will take place on Friday, 25 April.

Dyatlov has briefed the staff,

and they know what's expected of them.

(SPEAKING A FOREIGN DIALECT)

Everyone turned up expecting it to be a normal shift.

As it turned out, it didn't go that way...

..and not everybody would make it home alive.

Early morning.

Engineers are preparing to carry out a safety test

on Chernobyl's reactor Number Four.

This particular safety test was designed to see what happened

when the cooling water pumps lost electrical power.

Engineers will switch off four of the pumps

which cool the reactor to test the backup system...

..and it has to be done today.

It was the last day of the week before the start of a holiday season

in the Soviet Union.

They were under pressure to complete the task,

to complete the shutdown of the reactor

before that holiday season.

Two miles away in Pripyat,

Chernobyl workers and their families

prepare for the upcoming May Day holiday.

It's a normal spring day with lots of people being about.

This is late April in Ukraine.

It's beautiful weather, generally,

the time when you felt summer is coming,

the spring has turned the corner, it's gonna be warm and lovely.

Back at Chernobyl,

inside the control room,

preparations for the test are underway.

It's a vast room, a giant curving control panel.

Strange paving flooring.

It would have been filled with smoke,

everybody smoked at the time.

Overseeing the test,

Deputy Chief Engineer, Anatoly Dyatlov.

So, Anatoly Dyatlov

was probably the most feared person at the facility.

If he was in the room, you had to listen to him

and do what he said,

otherwise there'd be trouble.

The test is due to be carried out

by members of the plant's morning shift.

They've been trained on how to carry it out safely.

To operate the test,

the operators needed to lower the power output of the reactor.

This makes sense, if you're gonna test the brakes on your bike,

you don't do it at 50 miles an hour, you do it at five.

Operators have been gradually powering down the reactor since 1am.

By early afternoon,

the power's been reduced

to nearly 0.75 of the reactor's normal power.

(PHONE RINGING)

Inside the control room, the phone rings.

Partway through the day,

the emergency grid controller

asked them to stop lowering the power.

The energy was needed.

300 miles away,

another nuclear reactor has had an emergency shutdown.

Chernobyl must keep producing power.

Rather than say, "OK, we'll cut our losses

"and come back another day,"

Dyatlov decided, "No, we'll carry on.

"We'll do it this evening."

For hours, the reactor continues to operate,

but at a lower power.

The operators wait for the green light

to carry out the test.

They had to hold the reactor at a mid-power level

for a longer period than was expected.

Inside the reactor,

there's been a build-up of a dangerous gas called Xenon.

No-one really realised

that while working at that lower power level,

the reactor was reducing the chemical elements.

The so-called poisoning of the reactor was taking place.

Late in the evening,

and the test still hasn't taken place.

Chernobyl produces power 24/7

and there are constant shift changes.

The day shift transitioned into the evening shift,

transitioned into the night shift.

There wasn't the information passed through each of the operators

from day to evening.

New people came, the graveyard shift.

People who thought that by the time they come and start their shift,

the whole thing would be over.

Good evening, I'm Michael Usher. Here's what's coming

(PHONE RINGING)

After a nine-hour delay,

the control room is finally given the go-ahead to carry out the test.

So, it was the night shift

that were conducting the test.

It actually started about 11:00.

Ordinarily, the control room was a quiet place,

especially at that time of night.

Because the turbine test was taking place,

it was filled with people.

There were more than 20 people in the room that night.

One of the operators working the night shift

is Leonid Toptunov.

Leonid Toptunov

was one of the four operators

that took over the operation of the reactor.

He was a young and very clearly, talented engineer.

One of Toptunov's main jobs that night

was to keep an eye on the power in the reactor.

The final steps to start the test are taken.

So, having been left in this low power state all day,

the reactor was extremely unstable.

The build-up of Xenon gas inside the reactor

is causing it to behave erratically.

Because the operators were relatively untrained

and not prepared for the test,

they didn't really notice the signs

that the reactor wasn't in a safe state.

Operators know that if all goes wrong,

there is a safety mechanism in place.

Inside the control room,

something happens that sets alarm bells ringing.

The power dropped really unexpectedly,

which was unexplainable to the operators at the time.

If the operators knew enough about the issues and problems,

they certainly would avoid the accident.

Once power began to fall in the reactor...

..it carried on falling

and it fell to disastrously low levels.

The reactor was now in serious danger.

Toptunov takes steps to raise the reactor's power level.

But rather than bursting back into life,

the reactor's power only creeps up to a 16th of its maximum output.

Xenon gas has poisoned the reactor.

(ALARM SOUND)

The Xenon in the reactor was reducing the activity

to very, very, very low levels.

Toptunov can't increase the power to the level needed for the test.

People who were round him tried to help him.

Dyatlov, it seems,

wanted to carry on with the test regardless.

An argument reportedly breaks out

between Dyatlov and the shift foreman,

Alexander Akimov.

They were seen having quite a heated conversation,

and it's fair to assume that it was Dyatlov saying,

"I want to go ahead,"

and Akimov saying, "No, we should stop. It's not safe."

For nearly 24 hours,

engineers at Chernobyl's fourth nuclear reactor

have been attempting to carry out a safety test.

They were going to turn off the cooling system manually

and see what happened.

But even before the test starts,

they're struggling to control the reactor.

When the experiment was started,

it was already in an unstable state

but the operators didn't exactly know

what was going on in the reactor.

Deputy Chief Engineer, Anatoly Dyatlov,

insists the test should go ahead.

Operators of Soviet reactors

were kind of used to not exactly following the guidelines,

partly because the guidelines were confusing,

but partly 'cause it was quite difficult to operate

those particular reactors

without doing a few things that you shouldn't really do.

Operators, guys who were operating the controls

said, "We should stop,"

but Dyatlov just told them to get on with it.

The experiment was started at 1:23.

Four of the eight pumps

that were putting cooling water into the reactor,

the power was taken away.

When the coolant system was switched off,

that water was no longer coming up past the fuel rods quickly.

Any water that was in the system was boiled off.

The water was no longer being used to cool the fuel rods

and it bubbled off into steam.

This kind of causes the nuclear reaction

to actually start to speed up,

so with more boiling, more steam is produced.

The rate of fission increases...

Water that kept being pumped into the reactor,

with the aim of cooling it down, had the opposite effect.

The more fission increases, the more steam is produced,

more bubbles, and it's a positive feedback.

It's a never-ending cycle

until you get to a very dangerous, unstable point in the reactor.

In Reactor Four's control room,

Leonid Toptunov is monitoring the reactor's power level.

A few seconds into the test, he's scared by what he sees.

As the reactor overheated,

Toptunov finally saw this.

He called across, said,

"The temperatures are just skyrocketing inside the reactor."

With the reactor out of control,

there's only one course of action.

The emergency button

to shut the reactor down was hit.

The test had been running for just 36 seconds.

Instead of shutting down

when that emergency button was pressed,

the power continued to increase.

It keeps perpetuating

and keeps growing and growing and growing.

You have no water left in the reactor.

You have just steam.

The fuel channels ruptured.

The amount of steam increased.

You got more heat, more power, and a runaway reaction happened.

There's nothing that can be done at this point.

The Unit Four reactor explodes.

(EXPLOSIVE SOUND)

First thought that crossed the mind of some of them

was, "OK, it is probably an earthquake."

They wouldn't have been prepared

for what had happened inside the reactor.

Two people die instantly in the explosion.

Others are now being exposed to lethal doses of radiation.

Inside a nearby fire station, the telephone rings.

(PHONE RINGING)

The fight to save Chernobyl has begun.

(PHONE BEEP)

..with radiation pouring

out of Chernobyl's Number Four reactor...

The Soviet government does everything it can

to conceal the accident...

They couldn't control radiation,

so they were trying to control the information.

..with deadly consequences.

Nobody knows how many people died as a result of that delay.

Captioned by Ai-Media ai-media.tv