The Robot Assault On Fukushina

The 2011 Earthquake and Tsunami in Japan triggerred a catastrophe in one of the country's largest Nuclear Power plants. The Cleanup will take decades, and officials will need to locate all the lethal fuel remaining in the Pitch-Black. Debris strewn, water-filled vessels. It's no job for humans.

THE NIGHT BEFORE THE MISSION, KENJI MATSUZAKI COULD NOT SLEEP.

For more than a year, Matsuzaki and a team of engineers had been developing their little robot—a bread-loaf-sized, red and white machine equipped with five propellers, a transparent dome, front and rear video cameras, and an array of lights and sensors. Nicknamed Little Sunfish, it was engineered to operate underwater, in total darkness, amid intense radiation. And after three months of testing, training, and fine-tuning, it was deemed ready to fulfill its mission: to find and photograph the melted-down radioactive fuel that had gone missing inside the Fukushima Daiichi nuclear power plant.

More than six years had passed since an earthquake and tsunami hammered northeastern Japan and reduced the Fukushima facility to radioactive ruin. In all that time, no one had been able to locate the hundreds of tons of fuel inside the three reactors that had suffered core meltdowns. The uranium fuel had overheated, turned into lava, and burned through its steel container. That much was known. What happened after that was the big question. Did all the fuel flow out of the reactors, or was some still inside? Did it pile up in a heap, spread out in a puddle, spatter on the walls? Without knowing the answers to those questions, it was nearly impossible to devise a plan to get rid of it. And getting rid of it is imperative. Every day, as much as 165 tons of groundwater seeps into the reactors, becoming contaminated with radiation. And there’s always the possibility that another earthquake or some other disaster could rupture the reactors again, sending radiation spilling out into the air, sea, or both.