Narrator: Since Russian forces invaded in late February,
Ukrainian volunteers have mounted a desperate campaign
to keep their nuclear materials safe.
Narrator: On March 2, civilians blockaded a road
leading up to Europe's largest nuclear power plant.
Narrator: A nuclear bomb would be catastrophic.
But destabilizing the kind of waste stored at Chernobyl
and Ukraine's four other nuclear plants
could create a widespread environmental disaster.
So far, the war hasn't led to it,
but there have been several close calls.
Narrator: Russian forces fired on buildings holding nuclear fuel
and forced plant support staff to work at gunpoint for weeks on end.
Ukraine shared a video that they claim
shows proof Russians dug trenches
in the most contaminated area surrounding the Chernobyl plant.
Soldiers occupied it for a month
before handing control back to Ukraine.
Narrator: There's more than 250,000 metric tons
of radioactive waste all over the world.
What happens if one of these places
gets hit with a stray missile?
Or like in Fukushima, a massive tidal wave.
We took a closer look at sites in Ukraine
to better understand one of the most dangerous
types of worldwide waste.
In 1986, two explosions rocked the
Chernobyl Nuclear Power Plant
when workers botched a safety test of a particular turbine.
The resulting meltdown released around
400 times more radioactivity
than the atomic bomb in Hiroshima
and took the power plant offline for good.
Timothy: You had kind of a nuclear volcano that was erupting
and emitting vast quantities of this material into the atmosphere.
Narrator: That material poisoned 1,000 square miles
probably for thousands of years,
and wind spread radioactive ash across Europe.
Thousands of farmers had to abandon their crops
and cancel the sale of sheep that were exposed to radiation.
It created a disaster zone that needs to be
carefully and constantly monitored
to avoid further contamination
because the reactor is still there.
Thirty-one people died in the immediate aftermath.
And some studies claim as many as 4,000
will eventually die from exposure to radiation.
Decades later, in the most radioactive areas,
many animals are still showing the effects.
Timothy: And we've seen
increased rates of cataract in the eyes.
We've seen increased rates of tumors
on the bodies of birds and rodents.
Narrator: And to this day,
the plant employs thousands of people
who risk exposure to radiation
so they can monitor and do damage control 24-7.
They deal with seasonal wildfires
that threaten critical infrastructure
and release even more radiation into the atmosphere.
The Ukrainian government says its monitoring labs
were damaged in the fighting, so fires could burn undetected.
On March 27,
one Ukrainian official reported that
more than 10,000 hectares were on fire.
Wind could carry that radioactive smoke in any direction.
Wim: Keep in mind if Chernobyl gets hit,
the fallout will also hit Russia,
so it's not in their interest to get that going.
It's not that it's deliberate attempt to take something out,
but it's about someone making a mistake
which could have severe consequences,
and that's the biggest risk here.
Narrator: In 2019, a European initiative
called the Chernobyl Shelter Fund
completed a giant stainless-steel dome
to cover the reactor that broke down.
Timothy: This new cover, which is airtight essentially,
will allow engineers to get into the old reactor
and start dismantling it piece by piece.
There's enough fuel still sitting
in this old, bombed-out shelter
that it could generate a nuclear reaction.
Narrator: If that happens,
the old reactor could burn and cause a fire,
raising radiation levels around the facility.
It wouldn't be quite as bad as the original accident,
as the radioactive material has been stabilizing
for 35 years.
The actual reactor is one thing,
but the biggest threat is probably the 5 million pounds
of highly radioactive spent fuel rods
that need to be kept cool.
Timothy: The small rectangular building
that the old spent fuel's stored in,
in these giant swimming pools,
that's actually probably the most
concerning location on the site
in terms of stray missiles.
Narrator: These structures are designed to withstand a plane crashing into them,
but not necessarily missiles.
Timothy: There's no real way to get rid of the material.
Instead it's going to take centuries to millennia
to disappear completely,
depending on which isotope you're talking about.
Narrator: Ukraine generates over half of its electricity
from four nuclear plants.
The largest is in Zaporizhzhia to the southeast.
Crowds of civilians blockaded the road
leading up to that plant in March to try to keep it safe.
Narrator: At first, it worked.
The local mayor said that afterward,
Russian soldiers met with
plant representatives for negotiations.
But then a couple of days later ...
Narrator: Russian forces attacked the plant
in the middle of the night.
They even fired heavy weapons
in the direction of buildings housing radioactive fuel.
Narrator: Footage from inside the plant
allegedly shows workers pleading with them to stop.
Doug: It's got six reactors.
It's got huge amounts of radioactive waste
stored in the open air outside.
The sites being taken over militarily,
it's an extraordinary thing to see.
And it's something that the international community
doesn't seem particularly well equipped to deal with.
Narrator: Experts say taking over the plant
could be a strategic move.
Wim: Controlling those kind of power plants
also controls power of half of the country.
That gives you enormous leverage
when you're controlling an area, or in case of negotiations.
Narrator: A week after the invasion started,
Russian energy officials claimed control
over this second plant.
There are at least 440 reactors across the world.
And because they need a constant supply of cool water,
many of them are located dangerously close to coastal areas.
But radioactive waste is everywhere.
Globally, there's more than 1,200 times
the amount of radioactive waste there is at Chernobyl.
While some countries have designated nuclear trash cans,
like Yucca Mountain in Nevada,
these areas usually only store low-level radioactive waste.
The abandoned community of Hanford, Washington,
is home to 56 million gallons of radioactive waste
from a nuclear production site
that was decommissioned in 1989.
Now, nuclear waste from Hanford
is seeping into the water and soil in rural Washington.
As far as nuclear accidents go,
humanity has been extremely lucky so far.
The 2011 explosion in Fukushima, Japan,
could have been much, much worse.
Timothy: If the accident had happened
at any other time of the year, probably,
the radioactivity would have had
a much bigger impact on terrestrial systems.
Could have been going towards Tokyo.
Narrator: If the radioactivity had blown inland,
it could have forced the evacuation
of over 35 million people
and rendered some areas uninhabitable for a long time.
After the accident,
intergovernmental groups like the
International Atomic Energy Agency helped with the cleanup,
and they'd do the same in Ukraine if needed.
In 2016, two years after Russia annexed Crimea,
the UN passed a resolution introduced by Ukraine
on protecting the environment during armed conflicts.
That means the UN and the IAEA
would help manage any fallout.
In fact, the IAEA is already providing
technical support to Ukraine
and offered to broker an agreement
to maintain nuclear safety during the conflict.
But it doesn't look like the Russians will agree.
We asked the Russian government for comment, but they did not respond.
For now, war drags on.
Around a quarter of Ukrainians have fled for their lives.
If they return, the question is,
what kind of landscape will they come back to?