A Popular History of Unpopular Things
A podcast that makes history more fun and accessible - we love all things gory, gross, mysterious, and weird!
A Popular History of Unpopular Things
The Fukushima Nuclear Disaster
Join Kelli as she goes over the Fukushima Nuclear Disaster, where a massive 9.0/9.1 earthquake 80 miles off the eastern coast of Japan triggers a tsunami that killed tens of thousands and caused millions in damages. But the earthquake and tsunami also knocked out power to the Fukushima Daiichi power plant, which had terrible, terrible consequences...
In this episode, we briefly revisit what happened with Chernobyl so we can compare it to Fukushima, as both disasters received the same nuclear "disaster" rating. But what really happened with Fukushima, and what lessons can we learn from this most recent nuclear scare?
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Source referenced: Fukushima - The Story of a Nuclear Disaster by David Lochbaum, Edwin Lyman, Susan Q. Stranahan, and the Union of Concerned Scientists
The Fukushima Nuclear Disaster
Intro
Welcome to A Popular History of Unpopular Things, a mostly scripted podcast that makes history more fun and accessible. My kind of history is the unpopular stuff - disease, death, and destruction. I like learning about all things bloody, gross, mysterious, and weird.
Before we begin, a quick reminder that you can support me and the show on Patreon, just look up either A Popular History of Unpopular Things or APHOUT: A-P-H-O-U-T. And you can also now watch episodes on YouTube - so go subscribe to my channel there! I appreciate all the love and support :)
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So just before Christmas in 2022, I did an episode on the worst nuclear disaster in history - Chernobyl. I went over how nuclear reactors work and what went wrong with Chernobyl’s. And in that episode, I referenced Fukushima, probably the second most well-known nuclear disaster. And today I want to talk more about it!
On March 11th, 2011, there was an earthquake about 80 miles east of Sendai, a city on the northeastern coast of Japan’s biggest island, Honshu. It was a magnitude 9 to 9.1 earthquake, and to help understand how massive that is, the biggest magnitude earthquake ever recorded was a 9.5 magnitude earthquake that hit Chile in 1960. The 2011 event, also known as the Tohoku Earthquake, is currently the fourth-largest earthquake in recorded history. Tohoku is the region in Japan most affected, and where Sendai and Fukushima are located.
The underwater earthquake triggered a series of massive tsunamis that crashed into coastal towns and cities. The loss of life and property was tragic - I’ve seen estimates that place the death toll at over 18,000, and the damages at well over $300 billion in US dollars, making it the most expensive natural disaster in history.
And part of the reason it was so costly was because it caused a power failure at the Fukushima Daiichi nuclear plant, approximately 60 miles south of Sendai. And this power failure led to several explosions - a level 7 nuclear disaster, rated the same as the Chernobyl disaster in 1986.
So in today’s episode, we’re going to talk allllll about the Fukushima Daiichi power plant - what happened, what went wrong, was it anything like Chernobyl, could it have been prevented, and what’s happened in the years since?
As always, I’ll start with some context - scientific this time - so we understand how Fukushima’s power plant worked and how it was different from Chernobyl’s. Once we understand the basics, then we’ll take a look at the nuclear accident itself.
So let’s get started :)
Scientific Context
Now we know that the worst nuclear disaster happened at Chernobyl, where a safety test went horribly wrong. I’m not going to rehash what happened at Chernobyl, or how nuclear reactors work - go listen to my Chernobyl episode for a breakdown of nuclear science and how fission reactions work. But I wanted to incorporate Chernobyl a bit so we can compare the disasters - was the reactor at Fukushima Daiichi built the same way as Chernobyl’s reactor? And were the disasters similar? Well, no.
Chernobyl’s reactor, the RBMK-1000, was a graphite-moderated, water-cooled reactor. Graphite helped slow down neutrons to increase fission, and water kept the whole thing cool so the power didn’t go out of control. The biggest issue was with the RBMK’s control rods - the things used to moderate the fission reactions when they started happening too quickly. You put the control rods in, they absorb neutrons, and there are fewer fission reactions. But the RBMK reactors had graphite-tipped control rods, so the reaction actually sped up a little when the control rods were inserted, because graphite slows down the neutrons, increasing the likelihood they’ll smash into each other and initiate fission. And - without getting too deep into this - the control room operators found themselves in a position where they pulled all the control rods out, and when the power started spiking and they triggered the emergency switch to put all the rods back in, the graphite tips got stuck in the core which led a massive power surge that caused a steam explosion. This exposed the core to the air, which triggered a second, more powerful explosion. Then there was just radiation spewing out of the open core for a while until they could cap it off. Again, go listen to my podcast episode on Chernobyl - it is a fascinating story and one of my favorites.
But Fukushima Daiichi’s reactor was not graphite-moderated, water-cooled like the Soviet RBMK reactors. Fukushima’s reactors were what’s called a boiling water reactor designed by GE, Toshiba, and Hitachi. So let’s talk about how boiling water reactors work.
So the overall point of a nuclear reactor is to power turbines with steam. Sure, we could burn coal, and then use that heat to boil water, to create steam, but coal is a finite resource and a pollutant, kicking out all kinds of nonsense into the air that we don’t want. Nuclear power does the same thing but with fission. The heat produced from fission reactions is what boils the water, to create the steam, to power the turbine. It’s a cleaner energy source. And yes, I know there is an issue with what to do with spent fuel and whatnot… but in general, the scientific community considers it to be cleaner than burning coal.
So the boiling water reactor works as the name suggests - water circulates the core, which is hot from fission reactions, and turns to steam. The steam is then directed to the turbine generators. After pushing the turbines, the steam goes into a condenser, is cooled, converted back into water, and recirculated around the core to repeat the process.
Fun fact - some of the US’s nuclear reactors are boiling water reactors! Others are pressurized water reactors, which is the most-used design in the world. The main difference is how they generate steam from the water, but both use water as the coolant and moderator.
Anyways.
The Fukushima Daiichi plant opened up in 1971, and between its opening year and 1979, it built six boiling water reactors. And it generated a ton of energy - 4.7 gigawatts - one of the largest 25 nuclear power stations in the world. It was run by a company called TEPCO - the Tokyo Electric Power Company.
Now each of these boiling water reactors was surrounded by containment housing made of steel-reinforced concrete. This is pretty standard with nuclear reactors; it’s a failsafe meant to help contain radioactivity in the event of a problem.
I’ll also note that Chernobyl’s reactors did NOT have this steel and concrete shell around their reactors; just some regular concrete and a heavy lid, but the reactor itself wasn’t fully contained. A full and properly built containment housing was too expensive and the Soviet Union was more concerned with cost than safety. They operated under the assumption that Soviet science was infallible, so extra safety measures weren’t necessary. They learned that lesson the hard way.
So at Fukushima, you’ve got nuclear reactors inside their own containment housing, and then those structures were inside the reactor building as another layer of containment just in case. My point is - at Fukushima, and indeed in most nuclear power plants around the world, safety was definitely more of a priority than at Chernobyl… to an extent.
On the day of the earthquake and tsunami, only reactors 1 through 3 were operational; reactors 4 though 6 were shut down, surrounded in water, and served as temporary storage for spent fuel rods.
But while work was being done on those, and bigger plans drawn up for the spent fuel rods, reactors 1 through 3 were running normally. And then a the earthquake tested their safety precautions, and the Fukushima Daiichi reactors spectacularly failed.
The Fukushima Daiichi Meltdown
After the earthquake, sensors at the Fukushima Daiichi plant triggered an automatic shutdown - something we call SCRAM - of the Unit 1 reactor. The Chernobyl reactors had a SCRAM button too, the AZ-5 button. Pushing SCRAM inserts all of the control rods into the core, absorbing the neutrons that cause fission reactions, and therefore shutting down the chain reactions that sustain nuclear power. All of unit 1’s 97 control rods at Fukushima were inserted.
Shortly after, the SCRAM was triggered for units 2 and 3. Within a minute, all three operational reactors were shut down, which is great! This was what was supposed to happen. But even once SCRAM is triggered, and the chain reactions have stopped, and no new fission reactions are happening, there is still a tremendous amount of heat in the core. So what do we do about that? Well, we pump water around the core to help cool it. The heated water is then redirected to another water source to cool it down - in Fukushima’s case, it was the Pacific. So as long as the pumps are working, and coolant water is being flushed around the core, then the ten or so minutes after initiating SCRAM won’t lead to any issues. In addition, valves will periodically open and close to vent the steam and excess pressure - this helps prevent a build-up of dangerous gasses or steam, which could lead to an explosion, like what we saw at Chernobyl. So as long as we’ve got power, then all these emergency systems will keep things cool and depressurized while the reactor shuts down.
But unfortunately, the power to Fukushima Daiichi was cut by the earthquake.
Now there were failsafes in place in case something like this happened - once the power and backup power was cut to unit 1, 13 diesel generators kicked in, allowing that coolant water to continue pumping around the core. The primary concern with any nuclear incident is to make sure that the fuel doesn’t overheat.
Why? Well here’s what could happen.
If fresh coolant water can’t be pumped in, then the heat from the core will boil off the water that’s in there. Once the water levels drop low enough, the nuclear fuel rods are no longer completely surrounded in coolant water. They’ll quickly overheat and burst. The uranium fuel from within those rods, now exposed, will get hotter and hotter as it reacts with the air and elements around them, and they’ll melt, creating things like corium, a lava-like, radioactive mixture of nuclear fuel, elements created by fission, and other metals and structural items found around a reactor. This adds more radioactivity, heat, and pressure to the containment shell. After a few hours, the core and all that nuclear fuel and corium will melt and fall to the base of the containment housing, and if it stays hot enough, it will burn through that steel-reinforced concrete.
Once it’s burned through the concrete, it will continue to put radiation out as it burns through the secondary containment housing, the reactor hall itself. And inevitably, it will pump radioactive particles into the air, the soil, into the water table, and more generally the surrounding environment.
We don’t want the nuclear fuel to become exposed, overheat, melt through its containment housing, and then emit radiation into the environment. That would be death.
So to prevent this, we gotta make sure that water can be continually pumped around the core. That’s the most important thing. Which is why there was power, backup power, and diesel generators just in case.
But unfortunately for those at the Fukushima Daiichi powerplant on March 11, 2011, the earthquake wasn’t the only thing that tested their facility. Because in the wake of the earthquake… literally… was a massive tsunami.
Now the earthquake happened when one plate, the Pacific Plate, slid underneath the North American plate, which stretches around the northern Pacific and includes about half of Japan. Which I know is weird to think about - most of Japan sits on the North American plate, not the Pacific plate. But anyways, this plate shift and the ensuing earthquake displaced a ton of water. And that triggered waves that grew in intensity as they reached Japan only 80 miles west of the epicenter. And I read a fun fact in the book Fukushima: The Story of a Nuclear Disaster, which I’ll quote:
“By the time the waves hit Antarctica, about eight thousand miles south of the epicenter, they still had enough power to break off more than fifty square miles of ice shelf, twice the area of Manhattan.” End quote.
So if the waves were powerful enough to break up part of the Sulzberger Ice Shelf in Antarctica, 8000 miles away, imagine the power and strength of the water that pummeled Japan’s eastern coast!
The earthquake and tsunami did a number on Japan. Like I mentioned in the intro, I’ve seen the death toll estimates range over 18,000, and the damages at over $300 billion in US dollars. But I want to focus more on what happened to the power plant… because that’s why we’re all here.
41 minutes after the earthquake, the first tsunami wave hit Fukushima. There was a seawall, though, and it easily deflected the 13-foot tsunami wave. The wall itself was meant to withstand waves up to 33ish feet, or just over 10 meters.
Which, again, is unfortunate, because the second wave that hit 7 minutes later was 46 feet tall. I’ve read reports that it was 50 feet tall, as well. But either way, 46 or 50, it was taller than the sea wall and crashed into and flooded the power plant. It knocked out some seawater pumps that were designed to bring that heated water out of the reactors. It broke through the turbine halls and destroyed electrical panels, cutting power to the plant. It seeped into the basements of the building, where most of the backup diesel generators were working to make sure the reactors wouldn’t overheat - the biggest concern, right?
And according to that book I referenced earlier, two workers were in one of the basements and drowned down there. But I have to mention, every other source I’ve read tells me that nobody died as a direct result of Fukushima, so there are definitely some discrepancies. I’ll also note that the previously referenced book definitely has an agenda, so everything I read I took with a grain of salt. And you should too. In general. You’ve gotta cross-reference things and corroborate, otherwise you might be getting fed misinformation or a biased perspective.
Anyways, while some of the diesel generators were above ground and not damaged, the whole electrical system was ruined by the waves and seawater, so it didn’t matter - the station was completely blacked out. As I established just a bit ago, despite initiating SCRAM and shutting down the reactors, it was really important to make sure fresh water could be pumped in and around the cores to help cool down the remaining heat decay reactions still happening inside them. Without power, the pumps won’t work. Without the pumps, the core will overheat. And an overheated core will likely meltdown.
In the span of a few minutes, units 1 through 5 lost power, their electrical panels destroyed by seawater. There was not enough residual power in the system that could be redirected to help five reactors at once. And worse than that - without power, they couldn’t even see what was happening inside the reactors!
The biggest concern was the rising pressure inside the containment shell; there was no way to pump in fresh coolant or shuffle the heated water out into the Pacific. So, the next plan was to release pressure from the containment shell into the atmosphere. Not ideal, but it’s just steam pressure at this point - the goal is to prevent a meltdown, which would put radioactivity into the air. The boiling water reactors at Fukushima Daiichi had an emergency vent built in, which would do just that. But… there was no power to operate these valves from within the control room. And the emergency booklet didn’t explain how to operate them manually, because of course it didn’t. It took them hours to even find the valves and determine which ones could be manually opened.
And anyway, they were running out of time for that to even make a difference.
A few hours after the earthquake, some workers were sent up to the top floor of unit 1’s reactor hall to try and get some information on what was going on in there. When they got to the building, their dosimeters went off the charts; with radiation that strong, it was clear that unit 1’s core had at least partially melted down and the reactor fuel was now exposed to the air, even if it was still inside the containment housing. Soon enough it could melt down through the containment shell, the reactor hall, and into the environment.
Did the government know about this as it was happening? Yes. But, as is true of pretty much every government ever in a crisis like this, the leaders wanted to mitigate fears of a full-scale disaster. The last thing they’d need in a crisis is people panicking before they have all the facts. And keep in mind, the earthquake and tsunamis were doing a number on Japan - the focus was on saving lives there, not what was happening at the plant. Initially. A nuclear emergency wasn’t declared by the Prime Minister until just after 7 o’clock that evening, more than 4 hours after the earthquake. Evacuations began shortly after that.
Teams were sent in to vent Unit 1’s reactor hall, but the longer this whole crisis went on, the more radiation was accumulating inside the building. It wasn’t until almost 24 hours later that they were able to open a large vent, dropping pressure from within the containment shell and the reactor hall. So the next step was to find a way to pump in seawater; something, anything that would cool the reactor. Or what was left of it.
By 3:30 pm, March 12, the day after the earthquake, teams had gotten everything in place to pump in some coolant water.
And only six minutes later, an explosion ripped open the Unit 1 reactor hall, destroying the roof, damaging unit 2’s reactor building, and sending debris everywhere. It was a hydrogen explosion; hydrogen gas had built up as a result of a chemical reaction between the steam and the metal coating surrounding the fuel rods. But luckily, the containment shell around the partially melted down core was not damaged.
Two days later, unit 3 experienced a similar explosion. Though a partial meltdown occurred, the containment shell holding all that corium and radioactive fuel was intact. Just like in unit 1.
The next morning, unit 2 started to show early warning signs of an explosion - the water levels around the fuel rods and core were dangerously low, hydrogen gasses were building up within the containment shell and reactor hall, and there was no consistent power to do anything about it. Soon enough, an explosion rocked unit 2 as well, with evidence suggesting that the containment shell might actually have been breached, which would mean that, unlike with the explosions at reactors 1 and 3, radiation spilled out of the containment shell. Not good.
At the same time unit 2 was exploding, the fourth reactor, which remember was shut down and contained in a pool of water, was damaged. This mattered because of those spent fuel rods also contained with the fourth reactor - 783 of them. If the fuel rods were exposed to the air, then the metal casings would oxidize and breakdown, uranium would be out in the open, and radioactivity would start spewing from the reactor building. Suddenly, an explosion and fire broke out at the fourth reactor, putting a few holes in the side of the reactor hall, exposing everything to the air. Luckily, the fuel rods were still submerged, so crews could focus on making sure water was continually pumped into the coolant pools to prevent any more catastrophe there.
There had been four explosions over three days at units 1 though 4. Units 5 and 6 didn’t experience any issues. Without knowing much more, the primary concern was to get water in to cool the reactors. Which is sort of ironic, since it was water that destroyed the plant in the first place. And this happened, to an extent, before radiation levels in the area got so high that helicopters couldn’t get too close. Eventually, a team of firefighters was able to get seawater into Unit 1’s core, radiation levels fell, and more workers were able to get in and build new pipes that would pump seawater into the various damaged reactor cores.
The immediate crisis was over, and radioactivity spewing from Fukushima-Daiichi was lessening.
The Aftermath
While both Chernobyl and Fukushima-Daiichi are both rated at a 7 on the International and Radiological event scale, Japan’s government estimates that the amount of radiation released at Fukushima is only 10% of what was released at Chernobyl. But still. That’s a lot to have to clean up. It’s also worth noting, though, that, unlike the big exclusion zone that still exists around Chernobyl, 97.6% of Fukushima Prefecture is habitable and the people there live normal lives.
Similarly to liquidation efforts at Chernobyl, it will take decades of work to remove the nuclear fuel and spent fuel rods, completely dismantle the reactors (both the damaged ones and the ones that were left unscathed), and remove all of the buildings. The damaged reactors are still kicking out lots of heat, so they need constant cooling - and I’m recording this in 2024, so it’s 13 years later.
TEPCO has been making progress with the cleanup efforts, though. They’re making good headway in removing fuel rods and the spent fuel from some of the pools, like the ones at unit 4. They’re removing molten fuel debris from units 1 through 3, though they estimate it won’t be done until somewhere between 2040 and 2050. They’ve also been monitoring the ecological impact - how many radioactive particles have leeched into groundwater or the Pacific Ocean. According to a report to the IAEA in March 2024, radiation levels in the groundwater around the plant are below their targets, which is good. TEPCO has built over 1,000 tanks to store the more than 1.32 million tons of wastewater, or as one CNN article puts it to help visualize that number, enough to fill 500 Olympic swimming pools.
But in the short term, the people, and the Japanese government, completely turned against nuclear power as a result of what happened at Fukushima - all 54 reactors in Japan were decommissioned. And I didn’t really focus on the people much in this episode, but there were whole industries that suffered as a result - think about the fishing industry. If there’s one thing most people associate with Japanese food, it’s seafood, right? There was a huge concern with irradiated fish as radiation leaked into the Pacific, so the government suspended fishing there. Which is a shame, because that region of Japan provided the country with about half of its fish. The fishing ban lasted for a year, and even after it was lifted, TEPCO had fishermen collect samples to monitor radiation.
Luckily, the Pacific Ocean is huge, right? So any radiation that leaked into it was quickly dispersed in a way that renders it more or less harmless. Today, fish contain practically no evidence of radiation, and any further restrictions on fishing in that region were lifted in 2021. Other countries have also started importing Japanese fish again, so the industry is slowly climbing back from the brink of collapse.
In 2023, following all this good progress, the Japanese government announced it was going to release more than 1 million tons of filtered wastewater from the plant into the ocean. And this, as you can imagine, was met with a ton of backlash. Some of you might even remember hearing about this, it made international news, and rightly so. TEPCO and Japanese officials argued that it had to be done to continue with cleanup efforts - I mean, where else is this nuclear wastewater supposed to go? They argued that it would disperse into the ocean, just like it did a decade beforehand, and it would be fine. I tend to agree, because the experts at the IAEA weighed in on it - a slow and controlled release of filtered wastewater, over decades, will not cause any harm. But as you can imagine, the people were not super happy about this - including the fishermen who had only just gotten their industry back, though still just a fraction of what it was pre-Fukushima. For a long time, power plants in Japan weren’t even running anymore - there was just no trust for anything nuclear. I mean, can we blame Japan? They’ve had… quite the history with radiation.
However, in recent years, some of the nuclear reactors have been brought back online… after going through some testing and rounds of approvals by the Nuclear Regulation Authority. There are currently (as of June 2024, so if you’re listening to this or watching it in the future and that number has changed, you know, don’t come for me) there are currently ten reactors operating at six power stations in Japan, providing less than 10% of Japan’s power. There are more that can operate, but they haven’t been given the go-ahead to get started. We’ll see what happens in the ensuing years as Japan, and its people, recover and learn from what happened at Fukushima.
And I want to harp on this again, because it’s really fascinating. Despite how serious this nuclear accident was, and how deadly it could have been, it’s reported that nobody was directly killed as a result of the partial meltdowns and explosions. With Chernobyl, there were at least 30 reported, immediate deaths from the explosions and from acute radiation sickness. More than 60 have died since as a result of radiation sickness, though the numbers are likely higher given how everything went down there. But with Fukushima Daiichi, any deaths are related to the earthquake and tsunami, not the nuclear disaster.
The biggest takeaway here is safety - don’t assume that the worst won’t happen. They had proper containment units at Fukushina, absent from Chernobyl, which helped keep the radiation from getting as bad as it could have been. But they didn’t have a proper system in place for a complete blackout. And as a country with a history of tsunamis, with a nuclear power plant on the ocean that requires power to run safely, they should have assumed the worst when putting their safety guides in place. Which they didn’t. And they paid the price for that arrogance.
It’ll be interesting to see how Fukushima’s cleanup and development carries on in the future.
Outro
Thanks for joining me for this episode of A Popular History of Unpopular Things. My name is Kelli Beard, and I hope you’ve enjoyed the story of the Fukushima Nuclear Disaster. Thank you for supporting my podcast, and if you haven’t already checked out my other episodes, go have a listen!
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