Original subtitles

I was the first Western scientist invited to do scientific research with

complex expedition.

A small group of scientists who worked on forensic analysis of the remains of

the destroyed reactor, Unit 4.

The Soviet Union was collapsing.

They took me to the plant kind of undercover.

They dressed me up.

in workers' clothing, just under the radar.

I thought it was just, hey, let's take this American along kind of thing. But

no, it was get up, work, until you drop.

Pretty much every day.

People sometimes laugh at scientists, but that's because they don't understand

the sheer beauty of seeking the truth.

And that's what these people want.

This is where officials say a crime was committed.

It's here that engineers conducted the experiment that led to the explosion.

The destroyed reactor is still hot, buried deep within what the Soviets call

sarcophagus, a gigantic concrete tomb where the radioactive material will be

buried for centuries to come.

The structure of the sarcophagus was really a combination of improvisation

brute force.

When it was complete, the Soviet engineer said that the sarcophagus was

triumph of Soviet engineering.

But inside the ruins of the reactor building, around 190 tonnes of uranium

remained unaccounted for.

The scientists were worried about what's called the critical mass coming

together and restarting a nuclear reaction.

They noticed on their neutron detectors a spike of neutrons that led them

to believe that a critical mass had indeed formed and that a nuclear

had happened.

They were puzzled. They were worried.

So we've got to know where this fuel is.

Scientists from the Kurchatov Institute, the Soviet Union's chief research and

development agency for nuclear energy, launched what became known as the

Chernobyl Complex Expedition to locate the fuels.

It was this eclectic, almost ragtag group of scientists.

They were soft -spoken people just trying to get to the bottom of it.

I mean, they're getting dosed.

Everything is coated with varying degrees of contamination.

I mean, you don't want to stay in there.

I said, it's dangerous here.

As my boss said, Soviet radiation is the best in the world.

It increases hair and hypotension.

He's dead, though.

Some of the fuel had been thrown out of the reactor core by the explosion.

But it was assumed that the rest remained inside reactor number four.

. . . .

. . . .

Nobody had been inside the reactor, I hope.

Anybody who went in there would have been exposed to very high fields of

radiation.

It doesn't go any further.

It's stuck somewhere.

I ran and climbed into the reactor shaft.

I fixed the camera.

We

found

an interesting thing there.

That's when they noticed, what core?

There was no core.

There was nothing left inside the reactor.

And so the immediate question was, where the hell did the fuel go?

To help them locate the fuel, they would strap cameras to toy tanks

because they were the ones that could withstand the radiation in there.

Other more sophisticated robots failed.

They would have aerosol and air current detection methods.

And that's when the bigger picture started to emerge.

What happened was the core itself, the fuel and the graphite, basically were

percolating through the floor of the reactor cavity.

The fuel melted through and fell down onto the floor of the sub -reactor

There were holes that led to what are called steam distribution headers.

It flowed out the steam distribution headers and then...

two more floors down pipes into the water that was there.

Roughly 75 % of the fuel ended up in the lower regions of the reactor building.

They thought that they could have a critical mass coming together to restart

reactions.

So you have these great energies released, which would cause damage.

Thank God that never happened.

We later found out once the fuel broke through and spread out, it basically

itself down, right? It just froze in place. And you can see that to this day.

If you're going to be working in the kind of environment that the complex

expedition was, you really have to be dedicated,

dedicated to getting to the truth.

The Soviet Union was not about truth.

A year after the accident, it had become clear that the Soviet authorities

intended to lay the blame for what had happened almost entirely at the feet of

the operators.

In a makeshift courtroom in a building in the centre of Chernobyl, six men went

on trial today charged with safety violations that caused history's worst

nuclear accident.

The defendants face up to 12 years in jail if they are convicted.

The courtroom was packed with workers from the power plant and families of the

victims. The defendants are accused of allowing unauthorized experiments at the

plant, ignoring basic operating procedures and overriding safety

The judge made it clear that he wasn't going to listen to anything that

contradicted the official version of the event. It was effectively one of the

final show trials of the Soviet Union.

A chapter ended today in history's worst nuclear accident in Chernobyl in the

Soviet Union. Six Russian nuclear power plant officials who flouted safety

regulations were held criminally responsible for the deaths of 36 people.

They had to have a scapegoat, and that became the operators.

The verdict was all six guilty of varying degrees of criminal negligence.

Viktor Brukhanov, the former plant director, 10 years in a labor camp for

violations of safety rules, including a concurrent five -year sentence for abuse

of power.

The trial has been closed to foreign journalists and no detailed reports have

appeared in Soviet media.

So it's not known whether or how the accused defended themselves.

On the opening day, one of the defendants suggested some of the blame

the reactor design.

But that's the only thing that's been said publicly in their defense.

I didn't understand if I was a witness of the defense or a witness of the

prosecution. I don't know.

And they asked some technical question, I don't remember.

And that's it, they stopped.

I got out of the car and went back.

Yes, I had a feeling that the accident happened not only because of the

of the personnel.

After leaving Chernobyl, Steinberg eventually became part of an independent

commission that reopened the investigation into what had happened at

Data about the performance of the reactor during the accident was being

recorded.

In the immediate aftermath, all the documentation and data from the plan was

seized and returned to Moscow and classified.

The KGB classified the real reasons for the causes of the Chernobyl accident.

Any dissent from the official line that the operators were responsible was

essentially forbidden.

In the court that conducted the investigation.

Who conducted the trial?

The Supreme Court.

I then called, met the deputy chairman of the Supreme Court.

And he gave the good to open this room.

We worked there, found the documents that we needed.

And we, step by step, the work was going on for about a year and a half.

The evidence was in Salagraga.

It's clear that something is wrong.

They moved these evidence for 6 seconds.

And it allowed them to say that the personnel is guilty, that he violated

regime.

That is, they falsified it.

Yes.

The findings of Steinberg and the rest of the investigators finally brought to

light the true causes of the disaster.

The new information tended to shift the focus of responsibility from operator

actions to fundamental design flaws in the reactor itself.

The Chernobyl power station used RBMK -type reactors that was uniquely Soviet

technology.

There was nothing like that produced in the West.

RBMK type reactors are very large reactors, that is, large physically.

A core that was 14 meters in diameter and 7 meters high.

This is extremely large compared to reactors in the West, which have a

of maybe 3 or 4 meters.

The RBMK reactors had nearly 1 ,700 fuel channels that contained the uranium

fuel that produces heat.

That's used to boil water to make steam, to make electricity.

This core is so large, it's almost like having two reactors in one, one at the

top and one at the bottom.

One side of the reactor couldn't speak to the other side of the reactor.

So it forced the operators to keep careful watch over this.

The only way that the operators can control the reactor

is with control rods.

Insertion of the control rods tends to decrease the reactor power.

Removal of control rods causes the reactor power to increase.

The control rods are used by the operators to fine -tune the level of the

reaction taking place.

So it's really like having brakes and accelerator on a car.

The control rods are also used to shut down the RBMK reactor.

The emergency shutdown function on the RBMK, also called the AZ -5 by Soviet

terminology, was to shut the reactor down quickly in an emergency.

The 8Z5 system was designed to insert almost all of the remaining control rods

into the core at the same time.

And it was intended simply to bring the reactor into a safely shut down state.

During tests in 1983, nuclear engineers... at another rvmk plant in

had discovered that there was a disturbing anomaly about the way the az

system worked with a very low number of control rods inserted into the core of

the reactor when the emergency shutdown system was activated it could induce a

runaway reaction leading to a meltdown and an explosion of the core

They'd begun to make progress on modifying the emergency shutdown system.

And although the Chernobyl -4 unit was on the list as due for those

modifications,

They decided that they would just save it until the next scheduled maintenance

shutdown to make the fixes.

Information about this fault did not make its way down to the level of the

individual operators.

The operators were attempting an experiment to power the reactor when the

-site power had been lost.

The midnight shift came in, and they were told that they would conduct the

experiment. They were not expected to do this.

They had not been familiarized with the test protocol.

The operators had great difficulty in bringing the reactor up to a power level

that would make the test possible.

They had withdrawn an equivalent of 203 of the 211 control

rods from the core of reactor number four, making the reactor as unstable

as it was possible to be and very sensitive to any further changes in...

By the time the test actually began, the reactor was like a loaded gun just

waiting for someone to pull the trigger.

In the test protocol, The completion of the test was marked by the operators

pressing the AZ -5 button to release the control rods to shut the reactor down.

They pressed the AZ -5 button at 1 .23 AM.

Silence.

And then suddenly thunder, thunder, dust

that falls from the ceiling.

It was a design flaw of the control rods that ultimately caused the explosion.

The control rods are made of boron, which is a material that reduces the

reaction rate in the reactor.

Unlike most reactors, underneath those rods was sections of graphite, which

to increase the reaction rate.

If the rods were completely withdrawn, then this graphite was pulled into the

core.

Under normal circumstances, this graphite would never cause a problem.

But in this case, the core was already in such an unstable state that the

slightest additional power fluctuation could initiate a runaway chain reaction.

The AZ -5 button that was pushed by the operators inserted all the control rods

at once.

The problem was the graphite caused the power to increase at the bottom of the

reactor.

Power is shutting down at the top, but you had a power surge at the bottom.

The overall effect was disastrous.

It literally caused the reactor to explode, hence the building being

It was as if when you stamped on the brakes of a speeding car, it accelerated

instead of slowing down.

The Soviet version of events was that the accident began to occur and then in

panic. the operators pressed the AZ -5 button in order to try and shut down the

reactor.

It was good.

But those who were responsible for it, they didn't get any punishment.

There were others who were innocent.

The operators in Unit 4 on the night of the accident did not know the potential

consequences of triggering the emergency shutdown system.

The Soviets believed that their system was so superior that no mistake could

ever be made, that their technology was beyond reproach.

The reactor had been designed by people at the pinnacle of the Soviet scientific

state.

So if it came to a choice between making these people culpable for this

catastrophe and laying the blame at the feet of some lowly reactor operators in

Ukraine, then they were going to be the ones who took the fall.

The design flaws set them up for failure.

When the perfect storm of the circumstances, the actions, and the

problems came together, it was almost inevitable.

The nature of the Soviet system was such that denial, secrecy, and cover -up was

endemic to the way of their operation.

The truth Chernobyl is more of a metaphor for the failure of the Soviet

than it is a reactor safety story.

The increasing reporting about what had really happened and information

about the failures of the design of the reactor finally revealed to

citizens of the USSR that the Soviet Union did not in fact lead the world in

high technology.

The dramatic failures of the Chernobyl accident undermined one of the last

sources of Soviet pride.

The great trouble of our people is Chernobyl. But not the most important.

Because until we have our real state, Chernobyl was, is and will be.

Until we have our real state...

Good evening. Eleven Soviet republics agreed to form a new Commonwealth of

Independent States today and consigned the Soviet Union to history.

The Soviet Union saw itself as a great empire, and then one day that all came

crashing down.

With eleven signatures and a round of applause, the Soviet Union had ceased to

exist.

It was chaos.

People lost their jobs. They didn't have any food.

It was deeply humiliating for many Russians, for millions of Russians.

Gorbachev said he thought the Chernobyl accident was the ultimate cause of the

collapse of the Soviet Union.

Because huge numbers of people, especially in Ukraine, began to realize

the Communist Party protected itself.

It didn't protect us.

The Soviets' initial attempt to try to cover over the destroyed reactor

was a hastily engineered structure that they built in the summer of 1986.

It was leaky. It was not as structurally strong as it could have been.

It's way beyond its design life. It's crumbling.

We've already had a collapse in one part of the turbine hall with a very heavy

snow load. We see some very, very major structural damage there.

If it had collapsed, it could have stirred up some of the radioactive

caused additional release of some of the radioactive material that was within

it.

Because of these concerns, Ukraine and Western donors got together and created

structure to cover over the entire building, a very large structure called

New Safe Confinement.

Construction began on the New Safe.

In 2010, a massive international effort,

something like 40 countries and organisations played a role in funding

designing that structure.

It was hugely expensive as well, the best part of $2 billion.

This is actually one of the most ambitious projects in the history of

engineering. It is twice the length of a 747 aeroplane. It is the largest

movable land -based structure ever built.

The new safe confinement was actually built to be mobile and was built off to

the side of the reactor and moved on rails over the original building.

Over these nocks, we put the Teflon pads.

And basically, if you put a lot of them, you make your own sliding way for the

skid shoes to slide on.

Construction on the new safe confinement was a long and arduous process.

And it ended six years later in 2016.

It's a big tape.

uh for safety and ukraine and europe will be much safer now

ukraine unlike the soviet union very much wants to

be part of the international community and not an insular state

i

was standing on a roof doing a live shot from cnn ukrainians who who resist oh I

tell you what, I just heard a big bang right here behind me. I thought we

shouldn't have done the live shot here.

It was quite shocking that Russia had decided to send its forces into Kiev,

Ukraine, and the first explosions of that conflict were being heard.

Russian forces are said to have taken control of the Chernobyl power plant in

northern Ukraine, the site of the world's worst nuclear disaster.

A military advisor says staff members are held hostage.

as a potentially dangerous military confrontation around that nuclear

That could kick up all sorts of horrific radioactive material and cause that

massive catastrophe to repeat itself all over again.

The Russian soldiers ploughed across the exclusion zone.

They dug trenches in the forest, which is an extraordinary thing to do.

The amount of contamination absorbed by those soldiers is pretty shocking.

They will undoubtedly suffer health consequences of exactly the same kind

were suffered in Ukraine post the 1986 calamity at Chernobyl.

The Soviet Kremlin had an utter disregard for the liquidators, for the

firefighters of Chernobyl.

In the same way the Russian Kremlin had...

an apparent disregard for the welfare of the soldiers.

Shortly afterwards, the Ukrainians took back the Chernobyl exclusion zone.

The Russians found they had to fight for every square inch of the territory they

were going to capture.

You're looking at footage that shows a Russian drone with a high -explosive

warhead striking the shelter that covers the fourth unit of the Chernobyl

nuclear power plant, sparking a fire that was later contained.

Are you kidding?

Lobbing a missile into Chernobyl?

What possessed you to do that?

The strike on the new safe confinement structure underlines the nuclear threat

throughout the whole Ukraine conflict that it could cause another Chernobyl,

another nuclear disaster.

And that would be catastrophic.

When we left Chernobyl, I was a child, but I was put in a situation that not

even some adults can live through.

It feels that the situation repeats itself, that we again are forced to

our home.

When the Russians started the invasion in 2022, we left Ukraine

and moved to Luxembourg, and now we are here.

I hoped for better for my kids, but it didn't happen.

I always teach my children be adaptable and be resilient.

And Ukrainians are proved to be resilient.

Each of these terrible actions brought people a lesson of the consequences of

wrong actions.

And this and that is a huge grief, a huge trouble and a huge

harm for every people.

I think this accident had a psychological impact on everyone.

Our lives were divided before and after the accident.

We believed in our government, we believed in our science, that everything

be fine.

And we didn't perceive any danger.

I think the legacy of Chernobyl, 40 years on, isn't just in the minds of

The scars are physical as well.

These radioactive toxins caused a huge spike in thyroid cancer.

And you can go to Ukraine today, and you can see people who were around in 1986

when the catastrophe happened.

They've got little scars on their necks where they've had operation on their

thyroid glands.

to take out parts of the thyroid because they'd become cancerous.

I remember quite often I would hear that that person died, friend or neighbor or

colleague, just young people.

It was radiation, but doctors would not mention that.

So it was a silent war.

What to take from the story of Chernobyl?

That's a hard one.

What would I say?

To maintain open societies that can provide

checks and balances to the pride that comes with having

huge, complex technologies.

If I were to give a lesson for my grandchildren, tell the truth, no matter

bad the situation is, it can only be made worse by lying and being

I think that the Chernobyl story is arguably more relevant than ever, given

the causes of the accident lie in a government and a society.

that had completely lost touch with what the truth really was.

One of the things that I think we all learned is when the regime is serving

itself rather than the people, that's when power evaporates.

That's the moral binder, the truth.