The Insane Story of Japan s Chernobyl

It's just another ordinary day for Masao Yoshida. He's a 56-year-old engineer running a nuclear power plant. Like every day, he's assigning tasks, reviewing reports, and making sure everything is running smoothly. Little does he know that at this very moment, about 180 kilometers away, events are set in motion that will lead to one of the greatest disasters in the history of Japan. Just offshore, the earth starts trembling. A magnitude nine undersea megathrust earthquake shakes the region. The Japanese are used to earthquakes, but this one is different. It's the most powerful one the country has ever seen, and it will trigger a chain of events that will change the world forever. Japan has been hit by its biggest earthquake since records began. An explosion was heard and smoke seen. The images of destruction and flooding coming out of Japan are simply heartbreaking. Well, this is definitely not good news. This one is a bigger scale than anything this country has ever faced. There are new fears today that the reactor core being breached. There are now serious concerns about radioactive material leaks. Masao Yoshida is in his office when the earthquake strikes. By the time it's over, the entire nuclear plant has lost power. The quake has cut Fukushima Daiichi off from the electrical grid. Although they generate their own electricity, nuclear plants still rely on external power to operate. Fukushima Daiichi has six reactor units. Each reactor houses radioactive fuel rods. Nuclear fission generates intense heat that turns water into steam. That's steamed and drives massive turbines to produce electricity. The fuel rods continue to generate heat even when the reactors are shut down. That's why they need to be cooled at all times. The plant has emergency diesel generators, or EDGs, to keep the water pumps running in case of a power outage. Reactor 1 is an older model that instead uses an isolation condenser to cool the rods. Units 1 to 3 automatically shut down after the earthquake. Units 4 to 6 have already been offline for maintenance. With grid power gone, the backup generators kick in Masao Yoshida immediately evacuates his staff. The plant has a designated emergency response center with seismic filters to withstand earthquakes. Yoshida and parts of his staff shelter there. Disaster drills are routine, but when a real emergency unfolds, chaos takes over. Now, they need to stay calm and hope the cooling systems hold. Because if they don't, the worst-case scenario looms. A full-scale nuclear meltdown. The fuel rods could melt into an extremely hot and radioactive mass. That mass could reach temperatures of up to 2,000 degrees Celsius and melt through the reactor pressure vessel. It could leak into the environment and contaminate vast areas, rendering them completely uninhabitable for decades. The heat also builds up immense pressure inside the reactor. If it gets too high, the reactor could explode. At the ERC, Yoshida checks in with other operators across the plant. He's trying to assess the status of the reactors. Everything appears to be stable so far. The backup generators are running. The cooling systems seem to work. For a brief moment, everyone eases up a bit. But the earthquake was just the beginning. Events like Fukushima remind us why the world needs experts who can design safer systems and respond to crises. You will work around 80,000 hours in your life. That's plenty of time to contribute to something meaningful, like preventing AI-related catastrophe or reducing pandemic risks. But where would you even start? 80,000 Hours is also the name of today's sponsor, a nonprofit that's not selling you anything. Their only goal is to help you use your career to have the biggest positive impact possible. For over a decade, 80,000 Hours has researched the most effective ways to tackle global challenges, like AI risks and the spread of nuclear weapons. And everything they offer is completely free. A website packed with research, a job board with hundreds of high-impact opportunities, and a podcast featuring expert insights on a variety of important topics. Go to 80,000hours.org to get their free in-depth career guide and make your 80,000 hours count. Out on the water, waves start building. They're small at first, but grow larger and more powerful as they approach the coast. Fukushima Daiichi sits right on the shoreline. It's designed to withstand waves up to six meters high. But against this monster tsunami, the waltz don't stand a chance. A wave of almost 15 meters washes over the nuclear plant. Roads and pathways disappear underwater. Vehicles are swept away like paper boats. People run for their lives, seeking shelter on higher floors. About eight minutes later, a second wave strikes almost as high as the first. Containment buildings, turbines, offices, the flood just swallows the entire site. Yoshida monitors the situation from the ERC. A report comes in from the control room in reactor one. The tsunami has flooded the diesel generators. The lights are out and the instrument panels have gone dark. The isolated condenser at reactor one has lost signal from the control room and gone into automatic shutdown. Without electricity, the engineers have no idea what's happening inside the reactors. They don't know if a meltdown can still be prevented or if it's already well underway. Yoshida knows that this situation extends far beyond the power plant itself. He reports to the local and national governments. Throughout the afternoon, a team of engineers tries to restart the isolated condenser to cool reactor one, but they fail. While Yoshida and his team are fighting to cool the reactors, the outside world takes stock of the havoc the tsunami wreaked. The waves have inundated large parts of the eastern coastline. Miyagi Prefecture is among the most affected. These are the areas hit by the tsunami. Tens of thousands of people have lost their lives. 100,000 people are forced to evacuate and about a million homes are destroyed. The entire region is wrecked. But right now, the world's eyes are fixed on the looming nuclear disaster at Fukushima Daiichi. The workers at the plant are forced to get creative. They hook up car batteries to the instrument panels to restore the lights. Now they can finally read the parameters again and monitor the situation. Pressure inside the reactor is rising fast. Without cooling, the intense heat will boil the remaining water into steam and force the pressure even higher. There's only one option left to prevent an explosion. Venting. That's a last resort procedure where special valves are opened to release steam and reduce pressure inside the reactor. Venting might prevent an explosion, but it has a price. Radioactive material could be released into the atmosphere, causing extreme levels of contamination, which is why Masao Yoshida considers it the very last resort. Amidst the chaos, he's in close contact with the Tokyo headquarters of TEPCO, the power company that owns and operates the plant. But communication is difficult. People at HQ don't seem to grasp the gravity of the situation. Yoshida and his team feel abandoned. The water level in reactor one is checked every 15 minutes and manually recorded next to the gauge. It appears to be rising. Maybe the water is not evaporating after all. The staff is relieved. They don't know the gauge is wrong. The worst case scenario at reactor one is already fully underway. The meltdown is happening. Radiation levels on site start spiking on the very first night. Yoshida fears the worst. What if reactor one has a leak and is already releasing radioactive material? He receives new orders from TEPCO headquarters. The venting process must be started immediately to relieve pressure inside the reactor. But Yoshida hesitates. The plant is still without power, and without it, venting can't be done remotely. The valves have to be opened manually, which means Yoshida has to send his workers into potentially contaminated areas. The radiation there could already be deadly. He faces an impossible choice. Defy orders from the top or risk the lives of his team. The next morning, the government designates an evacuation zone. Residents within a 10-kilometer radius from the plant have to leave their homes. A few hours later, a helicopter touches down on site. It's Japan's prime minister, Naoto Kan. He says he wants to assess the situation firsthand, but it soon becomes clear why he's really here. To pressure Yoshida into starting the venting process. Minutes later, the prime minister and his helicopter take off again. Yoshida and his team prepare for their most dangerous operation yet. A group of young workers volunteers to open the valves manually. Yoshida calls them his suicide squad. The men are fully suited up, pushing forward through the dark corridors. It's incredibly hot, almost 100 degrees Celsius, and all around them, invisible radiation looms. They finally make their way to the valves. Radioactive particles escape in through the air, but at least the team is able to somewhat ease the pressure inside the reactor, or so it seems. A massive explosion tears through the air. The blast is heard for miles. It's reactor unit one, or more precisely, its roof. It has been blown apart. Four workers are injured. The superheated vaporizing cooling water inside the vessel reacted with the molten fuel rods producing hydrogen gas. Trapped beneath the roof, the hydrogen formed an explosive bubble and ignited. A huge amount of radiation is released into the environment and the entire world is watching live on TV. A steam hydrogen explosion. Officials are still trying to figure out how much radiation escaped. Fears of a nuclear meltdown. But official reports are contradictory. Japan's nuclear and industrial safety agency, NISA, talks about a nuclear meltdown before the explosion has even happened. TEPCO and the Japanese government deny it. The evacuation zone has expanded to 20 kilometers. More people are forced to leave their homes. For now, the wind is pushing the radioactive cloud out onto the Pacific. But if it turns, it could blow straight towards Tokyo. At the plant, another issue comes up. The staff is running out of fresh water coolant. But the reactors must stay cool at all costs to prevent another explosion like the one in unit one. Yoshida makes a critical decision to use seawater for cooling. Fire trucks start pumping seawater into the reactor cores. Everything seems to be going according to plan. But then Yoshida gets another call from TEPCO. TEPCO orders Yoshida to stop the seawater injection immediately. The saltwater will do irreversible damage to the reactors. TEPCO wants to avoid that, hoping that one day the reactors can be put back into operation. Yoshida faces yet another impossible choice. And this time, he defies the order. The team continues the seawater injection. It will later become clear that Yoshida's bold decision prevented an even greater catastrophe. Slowly but steadily, the reactor temperatures begin to drop. Two days later. Reactor three is rocked by a hydrogen explosion similar to that in unit one. Just moments before the blast, Yoshida had sent some of his men to check on reactor three. Now he's riddled with guilt. Did he just send them straight to death? Yoshida has the sinking feeling he may never make it out of there alive. He bows before his team to apologize for his bad judgment. But with the very next breath, he asks them for their help again, fully aware of the incredible risk they are taking. He is moved by how many of them agree to keep going. The cooling efforts continue. Helicopters and concrete pumps are used to spray the salt water into the reactors. But the rising radiation levels make it increasingly difficult to get close. The Geiger counters are now measuring radiation levels of 400 millisieverts per hour. That's a lethal dose for human cells and comes with a dramatic increase in cancer risk. And the day after, the bad news just keep coming. There's another explosion in reactor two in the morning and another one in reactor four in the afternoon. The wind has shifted too. For a while, there's a radioactive cloud heading straight for Tokyo. This is it, Yoshida thinks. The downfall of Eastern Japan. But giving up is not an option. Yoshida evacuates everyone who is not essential to cooling the reactors. A bus takes the employees to Fukushima Daini, another nuclear plant 17 kilometers to the south. Out of 750 staff members, only a core group of about 50 people remains. Japan's fate now rests in their hands. The group will later become known as the Fukushima 50. They risk their lives to prevent an even greater disaster. That same day, the government steps in front of the camera. It's the first time they acknowledge the health risks posed by rising radiation levels around the plant. Another day dawns and the situation is still far from under control. The fuel rods in reactor one are now half exposed. Electricity is back and the seawater injection continues. The fuel rods in unit two are also partially exposed. Radiation levels remain dangerously high. All across the site, smoke rises and fires burn. It's a truly apocalyptic sight. The Fukushima 50 are working day and night, pushing through under brutal conditions. They are in a relentless battle to keep the reactors from overheating. Yoshida and his team are determined to hold the line until the bitter end. Six days after the earthquake, Japan assesses the true scale of the disaster. The quake and resulting tsunami have devastated whole regions. Entire cities and landscapes are underwater. The plant has finally been reconnected through the power grid. The reactors can be cooled without interruption. But vast areas around Fukushima are so contaminated they remain uninhabitable for decades. That disaster has led to the release of massive amounts of radioactive material. One of the biggest concerns is the isotope cesium-137. It has a half-life of about 30 years, meaning even after three decades, half of the original amount will still remain. The radiation levels are so extreme that Fukushima is now considered the second worst nuclear disaster in history after Chernobyl. Cleaning up the area is a major challenge. Workers remove layers of contaminated soil from playgrounds, parks, and farmland. Houses and streets are hosed down to wash away toxicity. Millions of plastic bags are filled with radioactive waste. The images of Fukushima shake Japan and the rest of the world. And they stir anti-nuclear sentiment. In Tokyo, thousands rally when they learn about the country's plan to reopen the reactors idled in the disaster. In Germany, where anti-nuclear sentiment has been growing for years, Fukushima becomes the final tipping point. Just days after the Fukushima meltdown, Berlin announces a moratorium on nuclear energy. Germany will phase out nuclear power for good. 14 years have passed since the Fukushima nuclear accident, and the situation is still not fully under control. The fuel rods inside the reactor have yet to be removed. Cooling water continues to leak. And since nobody knows what to do with all that contaminated coolant, Tepco is gradually releasing it back into the ocean. The plant's operating company has faced harsh criticism during and after the disaster. They are accused of deliberately withholding important information and repeatedly downplaying the true scale of the catastrophe. Then-Prime Minister Naoto Kan accused Tepco of putting corporate interests above national security. The company did not officially confirm the nuclear meltdown inside the reactors until two months after it actually happened. And it took several years to uncover the full extent of human error. In 2015, a study found that the nuclear accident could have been prevented. Other investigations came to a similar conclusion. The staff at the nuclear plant had never been properly trained for emergencies. Reports say Tepco had been covering up safety risks for years before the accident, falsifying inspection and maintenance reports. Apparently, Tepco knew since the 90s that the plant could someday be struck by waves of up to 10 meters, but failed to take protective measures. In 2022, four high-ranking Tepco managers were fined billions. But Japan as a whole has paid a much bigger price. To this day, the area around Fukushima looks like one big eerie ghost town. Only a few people have returned home. The government has officially declared it safe, but many lost their trust or already built a new life elsewhere. Radiation levels remain extremely high in some areas, especially in the forests. And yet, the disaster could have been even worse without people like Masao Yoshida. He died of esophageal cancer two years after the meltdown. According to Japanese news reports, his illness was not related to radiation exposure. It was just bad luck.