An exclusive look at the world’s largest-ever nuclear cleanup

March 11, 2016 at 7:33 PM EDT
Five years ago, an epic tsunami off the coast of Japan triggered a triple-reactor nuclear meltdown at the Fukushima Daiichi Nuclear Power Plant. Ever since then, 7,000 workers have been laboring round-the-clock on a massive, and unprecedented, cleanup effort. Science correspondent Miles O’Brien takes an exclusive look at ground zero of the greatest nuclear disaster since Chernobyl.

HARI SREENIVASAN: Now: How do you rebuild from a cascade of disasters?

Five years ago today, Japan was rocked by a massive earthquake and a catastrophic tsunami. The Fukushima Daiichi nuclear plant was crippled by the tremors and waves, triggering a meltdown that forced roughly 100 thousand people from their homes, spewing radioactive material into the ocean and nearby countryside.

Science correspondent Miles O’Brien has a rare look inside Fukushima to see how the massive cleanup project is pressing forward.

His report is a partnership with PBS program “NOVA.”

MILES O’BRIEN: Fukushima Daiichi was one of the largest nuclear power plants in the world. Today, it is a busy, crowded, dangerous deconstruction site.

My invitation to see it up close was unique.

What next? Does three have a lot to…

But even with special permission, getting inside is not easy by design. Radioactive contamination levels have gone down, but not nearly enough to dispense with the Tyvek suits, three layers of socks and gloves and full face respirators.

It’s like being an astronaut on a space walk. Here, 7,000 workers are doing a job for which there is no playbook.

NAOHIRO MASUDA, TEPCO (through interpreter): What makes this so difficult is the lack of experience. Nobody in the world has done this before.

MILES O’BRIEN: Naohiro Masuda is the chief decommissioning officer for the Tokyo Electric Power Company, TEPCO.

NAOHIRO MASUDA (through interpreter): We still need to decide what we’re even going to do. For that, we need to rely on the knowledge of people all around the world.

MILES O’BRIEN: He relies heavily on this man.

LAKE BARRETT, TEPCO Advisor: For them to come out and to publicly say “We need help” is different for them.

MILES O’BRIEN: Lake Barrett is one of a very select group who has some experience with a job like this. He was the Nuclear Regulatory Commission manager in charge of the decommissioning of Three Mile Island Unit 2 near Harrisburg, Pennsylvania. It melted down in 1979.

LAKE BARRETT: Fukushima is much more complex. The damage is much greater. There’s three melted cores. But the fundamentals of how you address this and how you recover are similar.

MILES O’BRIEN: The daily details of this 40-year job are managed here in a radiation-shielded, earthquake-proof emergency operations center.

The superintendent is another TEPCO veteran, Akira Ono, on duty here since June of 2013.

AKIRA ONO, TEPCO (through interpreter): Ever since the disaster, we have been working here 24 hours a day 365 days a year. We’re ready to respond to anything that happens.

MILES O’BRIEN: His biggest problem is water, a steady torrent of radioactive water. When rain falls, it seeps into the soil, and flows toward the ocean.

The earthquake on March 11, 2011, created numerous breaches in the basements of the reactor buildings. The groundwater is contaminated after it mixes with water that is continuously pumped onto the damaged reactor cores; 100,000 gallons of newly tainted water is created here each and every day.

They capture and pump most of it into holding tanks, lots of tanks. They build one about every other day. A plateau above the destroyed reactors is now a tank farm, brimming with more than 1,000 of them.

But have they managed to stop all the radioactive water from leaking into the ocean?

KEN BUESSELER, Woods Hole Oceanographic Institution: What we’re hoping to find is a container full of water.

MILES O’BRIEN: In this lab at the Woods Hole Oceanographic Institution, they have been tracking radioactive water from Fukushima since the accident.

KEN BUESSELER: The level is still measurable and quite elevated, but it’s not anywhere near what it was at the peak of the accident.

MILES O’BRIEN: Oceanographer Ken Buesseler says readings in April of 2011 showed cesium levels 50 million times higher than normal at the plant.

KEN BUESSELER: The numbers dropped very quickly, but they also didn’t go down to zero. They didn’t go to the background as quick as you would expect if they had stopped the leaks.

MILES O’BRIEN: They hope to stop the toxic leaks by building a barrier. They have encircled the damaged reactors with 1,500 pipes that go 100-feet deep. They will be filled with coolant. The goal? Deep-freeze the soil, creating a mile-long water barrier.

The technique has long been used in construction to build tunnels. But can it work at this scale for years and years?

Dale Klein is a former U.S. nuclear regulatory commission chairman and now an adviser to TEPCO.

DALE KLEIN, TEPCO Advisor: If you have water flowing through the site and you build a barricade, water’s going to go somewhere. Do they really understand? Is it going to go over the wall? Is it going to go under the wall? Is it going to go around the wall? So, my concern is, there is probably a better way to do it.

MILES O’BRIEN: The long-term solution is to find and remove the uranium fuel from the four reactors affected. They have started the process by removing fuel that was in underwater storage.

At unit four, which was powered down when the tsunami hit, they built a structure over the damaged reactor, using it as a platform to carefully pluck out more than 1,500 fuel assemblies.

But in units one, two and three, where the reactor cores all melted down, radiation levels are much higher, making the task much more daunting.

LAKE BARRETT: People are probably not going to have access to those buildings for more than maybe minutes or two, so not enough to do defueling.

MILES O’BRIEN: And what about the melted fuel in the reactor cores? They aren’t even sure where it all is.

LAKE BARRETT: Is it in one big vertical lump on the floor underneath it, or did it come down and flow like lava in a volcano and move out to the sides? We don’t know yet.

MILES O’BRIEN: TEPCO has turned to a team of scientists and engineers from the Los Alamos National Laboratory for some assistance. They are helping build a device designed to see through the walls of the reactor buildings and hopefully make what looks like three-dimensional X-rays of the reactor cores.

These long cylinders are able to detect muons, subatomic particles created in space by quasars and supernovas that rain down on Earth. Muons are stopped, slowed or deflected depending on the density of the matter they are passing through. And uranium is very dense.

Physicist Chris Morris leads the team.

CHRIS MORRIS, Los Alamos National Laboratory: You can reconstruct the amount of material at the core in the reactor. And we can actually measure if there’s any uranium there, if there’s a lot of uranium there, how much is left.

MILES O’BRIEN: The detectors will be run for months to give engineers the sharpest possible picture inside a very hazardous place.

CHRIS MORRIS: Human beings aren’t going in there anytime soon. The radiation levels are very high. It kills robots.

MILES O’BRIEN: The robots they have tried here so far have offered up glimpses inside the melted nuclear cores, before failing in the face of a bombardment of radiation.

Japanese robotics engineers have their work cut out for them.

LAKE BARRETT: I believe it can be done. It can be done safely and it can be done successfully. But nothing of this magnitude has ever been done by mankind.

NAOHIRO MASUDA (through interpreter): I feel very reassured that, in the next 30 or 40 years, people from all over the world will gather in Fukushima to work and research the decommissioning. I’m hoping it will become a very lively place.

MILES O’BRIEN: Fukushima five years later, they have made progress here, but it is just the beginning of a marathon. This cleanup will rely on technology not yet invented, and the determination of people not yet born.

Miles O’Brien, the “PBS NewsHour,” Futaba, Japan.

HARI SREENIVASAN: Stay tuned this fall. Miles will have a new documentary on Fukushima for “NOVA.” And, right now, you can read his blog on the real heroes behind the nuclear disaster. That’s on our Web site,