Meltdown: Earthquake, Tsunami, and Nuclear Disaster in Fukushima

by Deirdre Langeland

  A woman named Katsuko Takahashi was trying to escape by car when the tsunami caught up to her. “I heard a rasping sound. Even inside the car, you could hear it. We were wondering what it was when, looking through the front windshield, all you could see were houses—houses everywhere.”

  One witness described the incoming wave as a “wall of pitch-black water.” The tsunami coming ashore mixed with soil, sewage, oil, and rubble to form a fast-moving black sludge. It climbed higher and farther than anyone had thought possible, reaching a peak of more than 65 feet and as far as 3 miles inland.

  In Ishinomaki, where students, teachers, and townspeople were still waiting on the school grounds, the wave surged up the Kitakami River and swallowed the Okawa Elementary School whole.

  In the town of Kesennuma, the water first appeared innocuous enough, traveling far inland along the Okawa River. In advance of the tsunami, much of the water retreated. Then it began to flow back in. Like a layer of new water being poured over the old, it rolled forward. Curious spectators gathered along the concrete walls that lined the banks. They watched as small boats left on the river’s banks were swept up and splintered by the power of the water. Still, it seemed unlikely that the river would overflow the high barriers designed to keep it from flooding. But the water kept coming. In minutes it had breached the walls and moved into the town with deadly speed. Residents climbed to the tops of high buildings and looked on in shock as a mass of inky water, littered with bits of buildings, ships, and Styrofoam cubes from a local factory, swept away their homes and neighbors. The water rose over the first and second stories of buildings before it stopped. That was the first wave. The second and third waves—the next rings in that ripple of displacement—followed close behind.

  * * *

  In Fukushima prefecture, the first tsunami wave reached the Daiichi nuclear plant at 3:27 P.M., forty minutes after the earthquake. It wasn’t tall enough to reach the reactors. But the second wave easily overtopped a flood barrier and swamped all six. The backup generators that had kicked in after the earthquake sputtered out.

  In Otsuchi, Ryoichi Usuzawa had found Taro and escaped the first wave by climbing onto his roof, carrying the dog. “From there,” he remembered, “I could see the whole scene. Otsuchi was a giant washing machine … Cars and houses that had been swept away came smashing into my house with a grinding sound. The volume was incredible. Amid the noise, I heard voices saying, ‘Please help—!’ and hissing sounds from leaking propane tanks. Car horns were beeping from alarms that had short-circuited.”

  For people swept up by the water, survival was unlikely. As the flood sluiced inland, the current was fast and strong enough to drown even the most accomplished swimmer. That speed, coupled with the possibility of being crushed by massive amounts of debris—including entire houses—made the flood virtually impossible to escape.

  A photojournalist for a local newspaper in the town of Kamaishi is caught by the wave around 3:25 on March 11. Although the water rose to his chest and swept him about 100 feet, he managed to escape by grabbing on to a rope and climbing onto a 30-foot pile of coal.

  As the tsunami swept through his home, Toshikazu Abe caught one last glimpse of his family. “I saw the exact moment when my mother was swept away by the wave. She was sitting on her chair,” he remembered. Then he, too, was carried away. He was pinned by the rubble, but by a stroke of luck, his head was above water. “Thirty seconds passed by. I knew if I swallowed water I’d be done for. I was able to keep my head up, floating out of the water, but I was stuck in the rubble and couldn’t move a muscle.” When the first wave pulled back, the debris around him loosened and sank, and he was able to climb onto a nearby roof. “My body hurt so much that I couldn’t move anymore … I eventually realized that I was bleeding everywhere.”

  At the hospital, patients were being moved to higher floors. Yukari Kurosawa followed them up. “Halfway up the stairs, I saw [that] the river already seemed about to burst its banks … An old man shouted, ‘The water’s rising! Everyone, everyone!’ Hearing him shout, I reached the third floor and took two or three steps when, from below, there was a crunching, snapping sound. Turning to look behind me, [I saw that] a cloud of dust was rising from the stairs I had just climbed. If I had been only a little bit slower, I might have been swallowed up, too.”

  It was a cold day even for March, with temperatures barely reaching 40 degrees Fahrenheit (°F). And the water was freezing cold. Many of those who had managed to escape the flood were drenched and shivering, which made the fires that came next almost welcome.

  Fires broke out when gas tanks and broken fuel lines ignited. Flames spread through the floating rubble and across the oily surface of the water. As they approached Toshikazu Abe, who was freezing on the roof, he had a strange thought. “This may sound crazy to you, and there was no doubt that I was in danger, but I thought to myself that the fire would be kind of warm and cozy. I wanted to warm myself up so I would be able to move and run away quickly.”

  After the first wave, Ryoichi Usuzawa clambered over the rubble between his rooftop and another building, holding on to a downed power line to keep from being swept away by the water. He clutched Taro the entire time. “At times, Taro’s leash and collar would come loose, and time after time I contemplated how much easier it would be if I left him behind,” he later said, “but when I saw his whimpering face … I was determined to save him.” By the time the second wave came, he had managed to get inside the second floor of the building. He was relieved when the second wave ebbed. But not for long: “Just as the water went down around my ankles, then five or six propane tanks at the convenience store next door simultaneously exploded. It was scorching hot, I couldn’t stand it. Sparks of fire were swarming around my feet. It was so hot, I thought my glasses might melt.”

  All along the coast of Iwate, Miyagi, and Fukushima, those who were lucky enough to escape the floodwaters scrambled to high ground. Some went to evacuation centers, only to find that the centers were in the path of the tsunami. Others who had found shelter had to evacuate again as fires spread.

  Survivors gathered on hillsides and the roofs of tall buildings. From those safe perches, many watched the incoming waves in shock. “Honestly, I couldn’t believe that only a minute ago this had been my hometown,” remembers Toshikazu Abe. “But I also felt that I’d been saved; I had survived.”

  * * *

  At sundown, it began to snow in earnest. Shivering people, many of them without blankets, food, or drinkable water, searched for dry clothes and huddled together for warmth. Many did not know what had happened to their families and friends. The lucky ones had been able to reach their loved ones by cell phone before the tsunami struck. Others wandered through evacuation centers, schools, and hospitals, looking for anyone with news.

  Across the island of Honshu, people were stranded by the earthquake and tsunami. This woman and child spent the night in a shelter in Tokyo.

  Ryoichi Usuzawa and Taro had been rescued from the rooftop of a floating house by firefighters, who took them to an evacuation center at a local community hall. “It was very, very cold,” he remembered later. “Within thirty minutes two elderly people passed away right in front of us. I thought, Ah, I might die, too. A public health nurse brought me some newspaper and when I wrapped myself with that, it was so warm. How can a little bit of newspaper be so warm? I wondered.”

  Sometime during the night, the snow stopped. The entire coastline was without power—no heat, no hot water, and no electric lights. In some towns, the sky glowed from the many fires sparked by the tsunami. But away from the light of the fires, many remembered seeing a spectacular blanket of stars.

  * * *

  In all, 154 square miles had been swallowed by waves and 127,000 homes destroyed. The survivors gathered at the Otsuchi hospital were trapped by the flood. But the hospital had blankets and fresh water, so they were better off than most. When the sun rose the next morning, a group of people gathered at a window that
looked out over what was left of their town. As they stood, staring in shock, someone said, “We’re all disaster victims now, aren’t we?”

  station blackout

  Friday, March 11, 2011

  Reactor Status

  Reactor 1: Scrammed

  Reactor 2: Scrammed

  Reactor 3: Scrammed

  Reactor 4: Shut down

  Reactor 5: Shut down

  Reactor 6: Shut down

  While Ryoichi Usuzawa and Toshikazu Abe were fighting for survival in the tsunami waters and Yukari Kurosawa was trapped on the top floor of the Otsuchi hospital, workers at the Fukushima Daiichi power plant were at the beginning of what would be a long struggle to prevent another disaster from happening. About 200 miles from Otsuchi, the nuclear plant’s operators spent the night of the tsunami working frantically in pitch-black control rooms desperately trying to stop a chain reaction that was spinning out of control.

  A sprawling collection of reactors and support buildings, the Fukushima Daiichi plant covered almost 1.5 square miles along the coast of the Pacific Ocean. Its six nuclear reactors were lined up along the shore behind three long, low buildings that housed turbines. Four of the six reactors, numbers 1 through 4, fell within the town of Okuma to the south. Reactors 5 and 6 were part of the town of Futaba, about 500 feet to the north.

  When most people hear the words “nuclear power plant,” they picture a giant funnel tapering upward from a wide base and belching steam from the top. That’s the shape of the nuclear plant where Homer Simpson works, and it’s a common shape for nuclear plant cooling towers. But nuclear plants come in all shapes and sizes. At the Daiichi plant, the reactors were housed in six square buildings that had been painted a cheerful baby blue. A splattering of white on one corner of each building mimicked the dappling of sun on the water. Inside was a series of containers, resting one inside the other like nesting dolls. At the heart of each nest, in the innermost container, was a nuclear boiling water reactor.

  This aerial view of the Fukushima Daiichi plant, taken shortly after the earthquake, shows the reactor buildings for units 1, 2, 3, and 4 (light blue). Turbine buildings lie between the reactors and the waterfront. The tall, scaffolded structures are exhaust chimneys.

  * * *

  At the most basic level, the majority of power plants work the same way: They boil water to create steam. The steam is used to turn a turbine, which generates electricity.

  Nuclear power plants also use this process—they boil water to create steam that turns turbines. But while other power plants burn oil, gas, or coal to generate the heat that starts the process, nuclear power plants use uranium. And rather than burn it to release energy, they use nuclear fission, a process that unlocks the energy stored inside a tiny, tiny package: the nucleus of an atom.

  A turbine power plant takes the energy stored in fuel and converts it into a form that can be used to power buildings.

  1. Fuel is converted into heat.

  2. Water absorbs the heat and produces steam.

  3. The steam travels through pipes and is blasted at a series of turbines, which rotate like pinwheels in the wind, powering the electric generator.

  Everything on Earth, from your breakfast cereal, to your dog, to your cell phone, is made of some combination of elements. Break those elements down to their smallest parts, and you will find a series of atoms. At the center of each of those atoms lies the nucleus, a mash-up of even smaller particles called protons and neutrons. The number of protons in the nucleus determines which element the atom is, which is important for your cereal and your dog and your cell phone, but it’s the neutrons that drive a nuclear chain reaction.

  In nuclear fission, the goal is to split the nucleus of an atom in two. Most nuclear reactors use uranium 235 as fuel. For an atom, uranium 235 has a pretty enormous nucleus, packed with 92 protons and 143 neutrons. Its large size makes the nucleus of uranium 235 unstable—to break it apart, all nuclear operators need to do is add some loose neutrons to the mix.

  Most of the physical size of an atom is made up of an electron cloud, which hovers around the nucleus.

  When a neutron traveling at just the right speed strikes the nucleus of a uranium 235 atom, it is absorbed and the atom becomes even more unstable. That causes it to fission, breaking apart into two smaller atoms. But if you could somehow put the two pieces back together, you would discover that your taped-together atom weighed less than it did originally. The missing mass has been converted into energy.

  Granted, it’s not a lot of energy. Splitting one uranium atom releases about 200 million electron volts. That’s about enough to make a single particle of dust jump—far from what’s needed to turn the turbines of a power plant.

  Fortunately, splitting a uranium atom doesn’t just produce energy. When the atom splits, it also sends loose neutrons careening from the break. On average, two neutrons break away from each uranium atom that splits. And those neutrons just might hit two more atoms, causing those to split. Those two atoms will each shed two neutrons, leaving four neutrons free to hit four atoms, which will release eight neutrons. On and on, the series of neutrons and atoms grows in what’s known as a chain reaction. One fission becomes two, then four, eight, sixteen, and thirty-two. In a fully functioning nuclear reactor, trillions of atoms are fissioning at any point in time.

  One fission can quickly become hundreds as neutrons spin off from each split and hit more nuclei.

  It all sounds easy enough, but in practice, starting that chain reaction is an extremely tricky process. When neutrons break free during fission, it’s impossible to predict where they will go. They may be launched outward, into the shell of the nuclear reactor. Or they may head into the heart of the fuel but still fail to cause other atoms to fission. While uranium 235 fissions easily, nuclear fuel is not pure—it is made mostly of uranium 238, which does not fission. Reactors like the ones at Fukushima Daiichi increase the likelihood that those pinging neutrons will hit another uranium 235 nucleus by slowing them down.

  The fuel used in a reactor is manufactured in pellets, which are stacked into rods and held together by a thin metal shell. In the reactor, each rod is surrounded by water. Water is made up of hydrogen and oxygen. And hydrogen atoms, as it turns out, are excellent at slowing down speeding neutrons. With just a single proton, the hydrogen nucleus has no particles that can be broken apart. When a speeding neutron hits a hydrogen nucleus, the hydrogen atom jumps, absorbing some of the neutron’s momentum, but it does not break. When neutrons fly away from one fuel rod, the surrounding water slows them to the optimal speed before they reach the next uranium nuclei, making them more likely to create fission. When they do, energy from the atoms is released as heat.

  Fuel rods are rigged together in an assembly that allows neutrons to travel from one fuel rod to another.

  Water is the workhorse of a boiling water reactor, performing three vital functions: It slows down the freed neutrons so the chain reaction is more likely to occur, but it also drives the turbines and cools the reactor. Water absorbs the heat generated by fission and evaporates into steam. That steam carries away the heat, and turns the turbine to generate electricity.

  Generating electricity is the whole purpose of the reactor, but cooling it is equally important. Without the water to cool it, the reactor would quickly grow so hot that it would melt.

  The challenge of running a nuclear reactor lies in keeping the number of bouncing neutrons inside it steady. When a uranium nucleus splits, its loose neutrons may never hit another uranium 235 nucleus. Or they may hit as many as three. That uncertainty means that nuclear engineers watch the overall reaction closely to make sure that things don’t get out of hand. A reactor that is producing fewer neutrons than it is losing will eventually wind down, the chain reaction broken. In a reactor that produces more neutrons than it loses, the chain reaction will continue to grow, quickly spiraling out of control.

  A reactor that is in balance, creating roughly the same number of neu
trons as it is losing, is called critical. To keep things in that perfect zone, engineers insert control rods into the reactor. Held together by a long metal frame, the control rods are long, thin poles made of a material, often containing cadmium, that absorbs neutrons. They can be moved into the spaces between the fuel rods, where they soak up the neutrons bouncing between them and slow down the reaction. When the control rods are pulled out of the reactor core, the reaction speeds up. If they are inserted all the way in, neutrons can’t travel between the fuel rods and the reactor grinds to a halt.

  * * *

  Before the quake, three of the reactors at Fukushima Daiichi, numbers 1, 2, and 3, had been critical, generating a little more than 2,000 megawatts, or approximately 2 billion watts, of electricity—enough to power about 400,000 homes. Reactors 4, 5, and 6 had been shut down for maintenance and inspection.

  When the earthquake struck, it shook Daiichi with far more force than the plant was designed to withstand. That day, there were about 6,400 workers in the massive complex. They grabbed hard hats and scrambled under desks to wait it out. In the main office building, ceiling panels rained down, trapping workers under their desks. Lights crashed from the ceiling. Somewhere in the shaking, an electrical tower toppled. Buildings went black.

  The plant had lost power, but it had multiple backups. Each reactor had two diesel generators, as well as batteries, that could power it in an emergency. The backup generators automatically kicked in.

  The six reactors on the site were grouped in twos, with a control room between each pair. At the time of the earthquake, ninety-seven operators were in the three control rooms. In the control room for reactors 1 and 2, even as the room pitched and swayed, the operators moved quickly to monitor an emergency procedure known as a scram. Triggered by emergency systems, control rods automatically shot up into the reactor cores, putting a damper on the movement of neutrons between the fuel rods. Operators checked the backup cooling systems to make sure they were working properly. In the control room for reactors 3 and 4, operators couldn’t check the backup systems until the quake had passed. In the end, though, the control rods were in and the chain reactions had been paused. It was a vanilla scram, with nothing remarkable to report. But everyone knew that a tsunami would be coming. The plant was located just feet from the ocean, and that meant workers needed to move to high ground. Outside the control rooms, they scrambled to evacuate. About two hundred people who were on the ocean side of the plant made a dash for the gates.