>> Japan will begin the process
from the tsunami wrapped plant
area final preparations are
being made inside the facility.
>> 12 years after the historic
meltdowns remains a toxic waste
site, upwards of 5000 workers
are here every day innovating
and orchestrating the most
complicated nuclear cleanup in
history.
>> It's interesting to see it
change quite a bit.
>> My guide is a nuclear
engineer who led the cleanup
after the three mile island
meltdown in 1979.
He is now a paid consultant for
Fukushima.
>> This is very similar.
>> This is a multibillion dollar
a year effort being spent at
Fukushima.
It's going to take some time to
complete this work.
>> Will you live to see it?
>> Probably not.
>> We began our tour as close to
the meltdown as humans can dare.
>> The rusty frames of the
structure, the original
structure.
They have the skill structure
all the way around.
-- Steel structure all the way
around to be able to dig down.
The ultimate goal melted steel
and uranium with all of the
radioactive isotopes.
Not too far from us.
You can't go in there.
Catching even a fleeting glimpse
is an extra ordinary challenge.
Intense radiation renders them
useless.
The path is a treacherous
labyrinth.
Different.
We were inside unit number five,
unscathed by the disaster, the
reactor is in your replica of
the three that melted down.
>> We are standing outside the
pedestal.
>> It was like being a mouse
inside of an engine.
A three-dimensional maze suited
by a contortionist.
>> We are underneath the unit.
These are the control rod
mechanisms.
That's where the reactor is.
This location
-- 20 feet below
is a concrete floor.
This is where the piles sit,
underwater.
40 or 50 beat above us.
This is on the floor.
>> The steady stream of
contaminated water has created a
problem.
At first, they were generating
between 130 and 160,000 gallons
of radioactive water every day.
In 2016, they completed the ice
wall, a $300 million
subterranean perimeter of pipes
cold enough to freeze the story
-- soil and keep much of the
groundwater at bay.
If you ask me, it's not easy and
water will continue to be
contaminated.
>> All about water sits in a
tank.
Almost 1100 tanks.
>> How long would it take before
they are not radioactive?
>> Going to be many decades, but
that is not possible.
>> You can keep tilting tanks?
>> They need to make room to
safely contain debris that will
be radioactive.
>> You have to build a variety
of facilities.
It's essential at this stage we
are now.
>> Before that, it flows through
treatment facilities designed to
remove 100 radioactive isotopes.
We had to add more protective
clothing, if one of these pipes
sprung a leak, the contamination
risk will be very high.
>> This is called the advanced
liquid processing plant.
>> Facilities can process about
300,000 gallons of water each
day.
>> It's a chemical process, not
a nuclear process.
>> I like that analogy.
In chemistry terms, that's what
it is.
He out -- other isotopes.
>> He says it removed 99.99%.
Trace levels with one exception.
An isotope called tritium.
>> Chemically, it's water.
>> It's a mildly radioactive
form of hydrogen that occurs
naturally, it's luminescent.
It reacts with oxygen just like
regular hydrogen, creating water
that's radioactive.
>> Must being considered.
The Japanese government is
planning to do the same.
Fishermen nearby and other
countries throughout the region.
More on that we continue our
series.
I am miles o'brien.