Inside the Meltdown This World

Last year, seven days after the tsunami that devastated Japan,

firefighters headed into the critically damaged Fukushima nuclear complex.

Three reactors were in meltdown.

The mission was to navigate through radioactive debris

and spray water onto lethal nuclear fuel.

If they failed, the government feared that radiation would

leave a vast area of Japan uninhabitable.

This film uses unique video from the front line of the disaster

and footage we filmed later with the men who fought to save the reactors.

It's the inside story of the Fukushima meltdowns -

told by those who were there.

It's the story of lives upended by the radioactive fallout.

And the story of a prime minister who gambled with lives

to avert even greater catastrophe.

The earthquake that shook the Fukushima Dai-ichi nuclear power plant

was the most powerful to strike Japan since records began.

The corporation that operates the plant, TEPCO,

has forbidden its workers from speaking publicly.

But, one year on, some are telling their stories.

Japanese power plants are designed to withstand earthquakes,

and the reactors automatically shut down within seconds.

But the high radioactivity of nuclear fuel rods

means they generate intense heat even after a shutdown.

So backup generators kicked in to power the cooling systems,

and stop the fuel rods from melting.

Takashi Sato, a reactor inspector who no longer

works at the plant, kept a detailed log of what happened that day.

Just up the coast, the fishermen of Fukushima knew what was coming next.

Yoshio Ichida wanted to save his boat.

He was gunning straight into the biggest tsunami waves

to strike Japan in hundreds of years,

hoping to crest them before they broke.

The highest of the waves was more than twice the size of the sea wall

guarding the nuclear power plant.

At the nuclear plant,

a worker was filming as his colleagues fled to higher ground.

At 3.35pm, the biggest of the waves struck.

TEPCO had been warned by scientists

that its tsunami defences were inadequate,

but had taken no action.

The company says it was still reviewing the matter.

Now the tsunami overwhelmed the sea wall

and began to swamp the nuclear plant.

Yukio Murakami - not his real name - is a senior TEPCO nuclear engineer,

who still works at the plant.

He's asked for his identity to be hidden

because of the company's ban on interviews.

Most of the backup diesel generators - needed to power the cooling systems - were located in basements.

If they were no longer working,

the nuclear fuel could eventually melt down into the ground

and release catastrophic amounts of radiation.

This is the frantically scribbled log

the engineers kept in the control room,

as the nuclear plant slid towards disaster.

"15.42 - nuclear emergency declared.

"15.58 - loss of water-level readings.

"16.36 - emergency core cooling system malfunction.

"No water is being injected."

The executives of TEPCO - one of Japan's biggest and most powerful corporations -

had never imagined that one of their nuclear plants could lose all power.

They had no plan for what to do next.

In the 90 minutes since the tsunami,

Japan's government had been scrambling to deal with

one of the biggest natural disasters in the country's history.

Now, the prime minister was informed that the cooling systems

had failed at Fukushima.

The government sent out emergency generator trucks to the stricken plant.

To avoid a meltdown, every minute mattered.

But the trucks were soon snarled in traffic caused by the earthquake.

Two hours had now passed since the tsunami.

The coastline was devastated.

Around 20,000 people were dead or missing.

Norio Kimura, a farmer from Fukushima,

lived just two miles from the nuclear plant.

He'd been out working when the waves struck.

Now he was searching for his family.

Survivors were gathering at the local sports centre,

unaware of the unfolding nuclear crisis.

Norio's father was missing.

So was his wife, and his youngest daughter, Yuna.

As night fell,

the Japanese government ordered a precautionary evacuation

of everyone within two miles of Fukushima Dai-ichi.

But Norio and others ignored the order

and kept searching for their families in the shadow of the nuclear plant.

The first generator trucks arrived at the plant as midnight approached.

The reactors had now been without power for more than seven hours.

But the generators needed to plug into a distribution board,

which was in a basement.

The relief plan had failed.

The engineers now faced a full-blown nuclear disaster,

and had no working instruments to reveal what was

happening inside the reactor cores.

They resorted to desperate measures.

The scavenged batteries allowed vital monitoring instruments

in the Reactor One control room to work again.

Just before midnight, the workers restored power to the pressure gauge.

The readout caused panic.

The engineers realised the rising heat

of the fuel rods in the reactor core

was creating massive amounts of radioactive steam and hydrogen.

The resulting pressure

meant the workers could not get water onto the fuel.

Even worse, it meant the containment vessel might explode,

a disaster that could leave parts of northern Japan

uninhabitable for centuries.

In Tokyo, the prime minister received a chilling message.

The workers in Fukushima urgently needed to release the radioactive gases into the atmosphere

before the reactor exploded.

Radiation has long been a sensitive subject in Japan.

After America dropped atomic bombs on Hiroshima and Nagasaki in 1945,

tens of thousands died of radiation sickness and cancers.

Yet now Japan's prime minister felt he had no choice

but to authorise the deliberate release of radioactivity.

But there was something TEPCO wasn't telling the government.

The company had never envisaged

they might have to vent a reactor without electricity.

They didn't know how to do it.

In the darkness of the Reactor One control room,

the workers pored over blueprints

to try to work out how to open the vents.

The handwritten plant logs show that radiation levels were now rising.

The engineers suspected something that the government and TEPCO

would not acknowledge for months - nuclear meltdown had begun.

Back in Tokyo, six hours after the order to vent the reactors,

there was still no news from the plant.

The government was starting to suspect

that TEPCO was hiding the truth from them.

The prime minister made a sudden decision.

He would go to Fukushima Dai-ichi himself.

At Fukushima Dai-ichi,

the prime minister met directly with the TEPCO engineers.

He insisted they vent the reactors.

The plant manager, Masao Yoshida, was known for his straight-talking.

He knew the radiation near the vents was at potentially fatal levels

but he told the prime minister he'd send in a suicide squad if necessary.

The prime minister returned to Tokyo.

He knew his orders might condemn the men who went into the reactors to death,

but he felt Japan's future was at stake.

But still the venting did not happen.

News had reached TEPCO that the evacuation of the surrounding villages

was not yet complete.

People were still searching for missing family members

in the devastation of the tsunami.

If the reactors were vented,

they could be exposed to dangerous levels of radiation.

One of them was Norio Kimura.

Norio had found one of his daughters, Mayu.

But he was still searching for his youngest daughter,

his wife, and his father.

Now he faced a choice - abandon the search,

or risk exposing his surviving daughter to radiation.

By just after nine o'clock on the morning of March the 12th,

the villages around the plant had been evacuated.

TEPCO ordered the venting teams to go in.

The plant logs show the first team of two workers set off at 9.04am.

This footage was filmed by TEPCO seven months later,

when radiation levels remained dangerous.

It shows the reactor building where the venting team had to operate.

Each worker was limited to 17 minutes in the reactor building.

After nine minutes, the workers found the wheel for opening the vent.

They inched it open, then pulled back when time ran out.

More teams followed, each spending just minutes in the reactors.

One of the workers received a dose of radiation greater than

the usual limit for five years of work at the plant.

That afternoon, a thin plume of gas signalled that

the pressure in the reactor core was falling.

The venting teams appeared to have saved north-eastern Japan

from a catastrophic explosion.

The Fukushima workers now had some power back in the control centre.

They began to think the worst might be over.

With the venting complete, the workers could focus on

getting vitally needed water into the reactor cores.

Suddenly the ground shook.

The engineers feared that the reactor core itself had exploded,

scattering radioactive fuel over the plant.

In the control centre, they watched the radiation levels

and waited to learn if they would live.

Later, in his only authorised comments to the press,

the plant manager Masao Yoshida revealed that he feared the worst.

After an hour, the radiation levels stabilised.

The engineers worked out what had happened.

Leaking hydrogen had exploded in the roof of the reactor building

but the reactor core itself was intact.

In Tokyo, the prime minister's chief cabinet secretary

was playing down the crisis.

But behind the scenes, the Japanese government

knew that the situation was sliding out of control.

The explosion had halted efforts to get water onto the reactor cores.

It was now only a matter of time

before the fuel would melt through into the open,

spewing out much worse levels of radiation.

Already a plume of radiation from the gas released in the explosion

was drifting across Japan.

The government widened the evacuation zone,

ordering everyone within 12 miles of the plant to flee.

Norio Kimura and his surviving daughter were in that danger zone

when they got the news.

On the afternoon of March the 12th, a mass exodus began.

The world started to realise that things were going badly wrong in Fukushima.

More than 100,000 residents evacuated from the villages around the plant.

What they didn't know then was that some were fleeing into

even greater danger, straight into the fallout.

To this day, what happened remains a source of anger for the evacuees.

Nozomi Hirouchi and her young family fled their village on the day of the explosion.

The previous day, her father had been killed in the tsunami.

That day, a government computer system known as SPEEDI

predicted that the radioactive fallout would settle

exactly where some of the evacuees were heading.

But officials at the nuclear safety agency, NISA,

say they were unwilling to give the data to the prime minister

because they weren't sure it was accurate.

In the district of Tsushima, 20 miles north-west of the plant,

thousands took shelter, thinking they'd reached safety.

In fact, radiation levels were higher than at some parts of the nuclear plant itself.

These doses were not life-threatening

but have left evacuees desperately worried about their health.

The Hirouchis' third child was born just after the evacuation.

65 hours had now passed since the tsunami.

At the Fukushima plant, the workers faced a new crisis.

The explosion had set back efforts to get water into the melting cores

of Reactors One and Two.

Now Reactor Three was also in meltdown.

TEPCO needed help.

A specialist team of soldiers was ordered to the site.

Another hydrogen build-up meant the Reactor Three housing

could explode at any moment.

Colonel Shinji Iwakuma and his team wore suits

that shielded their bodies from radioactive particles

but provided no protection against lethal gamma rays.

Their mission was to inject water directly into the core of Reactor Three.

The soldiers were now surrounded by lethally radioactive debris.

They were injured in the blast

but managed to flee the scene before anyone received a fatal dose.

Conditions at the plant were now becoming untenable.

Radiation near one of the reactor buildings had risen

to 1,000 millisieverts per hour.

After one hour of exposure at these levels, radiation sickness sets in.

A few hours would mean death.

As night fell, the news was passed back to TEPCO HQ in Tokyo.

The corporation began to consider withdrawing its workers from the plant.

What happened next has become one of the most controversial chapters in the story of Fukushima.

That night, the prime minister was woken with a disturbing message.

He was told that TEPCO planned to withdraw every last worker -

total surrender.

There was no mention of leaving some men behind

to keep control of the plant.

At that moment in Fukushima,

the plant manager Masao Yoshida had gathered all the workers together.

Meanwhile, the prime minister was arriving at TEPCO headquarters in Tokyo,

determined to stop the withdrawal.

He demanded to speak to TEPCO's executives.

Via a video-link, he was watched by the engineers in Fukushima.

TEPCO's executives still deny that they ever intended

to withdraw all of their workers.

That morning, they agreed to keep a skeleton crew at the plant.

They were to become known as the Fukushima 50.

For now, they were locked down in the central control room.

Hundreds of workers were on standby a few miles away -

ready to lay pipes that could pump water into the reactors.

But the radiation levels were now too high for them to approach the plant.

A team of American nuclear specialists,

who'd just arrived in Japan,

were fearful that TEPCO and the government were now out of their depth.

We were given very low numbers of people who were on the site,

and we knew that that wasn't sufficient

to do what needed to be done at that time.

That day, frustrated at the lack of information the Japanese were giving them,

the Americans decided to fly a surveillance drone over the plant.

The data they got was disturbing.

A third hydrogen explosion

had exposed pools of discarded radioactive fuel to the atmosphere.

These spent fuel rods were still highly radioactive.

If the pools boiled dry they could catch fire,

and the contamination could be even worse than a reactor meltdown.

We had some pretty clear indication that there was fuel damage occurring

in the spent fuel pools from lack of water.

As they were worried about Japanese citizens, we were worried about American citizens

and we thought, to put all this to rest, put water in there.

The Japanese prime minister ordered a desperate tactic -

dumping water on the spent fuel pools from the air.

The first crew to take off knew that Soviet pilots who'd done this

during the Chernobyl nuclear accident

had subsequently died of cancer.

A reconnaissance mission had been abandoned

because of high levels of radiation over the reactors.

Tungsten plates were now bolted to the helicopter.

The crew knew they had to drop the water on the move, from 300 feet.

If they went higher, they'd miss.

If they went lower, they could receive dangerous doses of radiation.

Their target was beneath them.

The world watched the mission live

via a camera placed 20 miles from the plant.

But on their second mission they missed.

Other helicopters followed

but the wind was too strong for accurate aiming.

The American nuclear team was monitoring the operation.

We were taking radiation measurements ourselves

to see, after the drop, did the radiation level go down?

Er, and it didn't.

The United States government began to draw up secret plans

to evacuate 90,000 of its citizens from Japan.

All British citizens within 50 miles of the plant

were advised to leave the area.

The Japanese evacuation zone remained at 12 miles.

US surveillance now suggested that there were flakes

of deadly radioactive fuel scattered around the reactors.

This meant that anyone who even approached the plant

would be risking their lives.

Despite the danger, the Japanese government ordered a team

of Tokyo firefighters to get water into the fuel pools by any means.

The men had no experience of working in radioactive conditions.

Their captain went ahead to plot a route.

But the radiation he was exposed to

meant he couldn't accompany his men on their mission.

The plan was for the firefighters to park a truck by the sea

to suck up water, then lay 800m of hose

and leave it spraying into the fuel pool.

Unique footage filmed that night -

from the front line of the nuclear disaster -

shows the firefighters preparing to approach the reactors.

They gave themselves 60 minutes to complete the mission.

Any longer would expose them to excessive radiation.

A radiation-monitoring vehicle set off in front of the firefighters.

Within minutes, the route was blocked.

The firefighters now had to lay the hose by hand,

taking readings as they went.

The alarms on the dosemeters signalled a dangerous increase in radiation.

A level of 100 millisieverts would mean the firemen would face

an increased risk of cancer if the mission took longer than an hour.

After 60 minutes on site, the hoses were finally connected.

As the firefighters withdrew,

radiation levels at the plant began to fall.

The men started back for Tokyo.

Some had still not told their families what they'd been doing.

With radiation levels lower, TEPCO seized their chance.

The hundreds of workers who'd been on standby headed into the plant.

Their mission was to lay miles of pipes that would channel

a constant flow of water into the reactor cores.

They had to work fast in case radiation levels spiked again.

Once again,

TEPCO has forbidden these workers from telling their stories.

But some have chosen to speak out.

TEPCO says most of their dosemeters were washed away in the tsunami,

but that they ensured each group of workers had one.

When the pipes were laid,

a steady flow of water at last started to cool the reactor cores.

After days in fear of death,

the workers in the control centre began to feel hope.

Weeks of difficult and often dangerous work lay ahead.

But the fight-back had begun.

Later, the workers lowered a camera into one of the reactors.

The flashes of white are caused by gamma radiation.

TEPCO now thinks that the molten fuel in Reactor One

finally came to a halt

in the concrete shell at the bottom of the containment vessel.

The radiation released by the Fukushima meltdowns

contaminated hundreds of square miles of north-eastern Japan.

More than 100,000 people fled the fallout.

Norio Kimura moved to the mountains of Hakuba.

Only here, on the other side of the country,

did he feel his surviving daughter was safe from radiation.

In the weeks after the tsunami, the bodies of his wife and father had been recovered.

But his youngest daughter, Yuna, was still missing.

Four months after the disaster,

Norio is travelling back to Fukushima.

An exclusion zone is still in force for 12 miles around the plant.

Animals abandoned by their owners have starved to death.

Others roam wild.

Just two miles from the nuclear power plant,

the evacuees from this village

are holding a ceremony for those who died in the tsunami.

For Norio, it's a chance to say farewell to the life he had

before the nuclear disaster, and the daughter he had to leave behind.

The coastline where Norio once lived may be uninhabitable

for more than 20 years.

Subtitles by Red Bee Media Ltd