Fukushima and Three Mile Island accidents Explained

Nuclear physics and simulation of some of the most infamous nuclear accidents: Fukushima and Three Mile Island. In this video, we’ll dive into the physics of nuclear reactors and simulate various reactor behaviors, including neutron moderation, control rod functionality, and decay heat management. Discover why these accidents happened, despite both reactors having passive safety features meant to prevent meltdowns.

We'll break down complex concepts like uranium fission, neutron moderation with light vs. heavy water, and the role of decay heat that makes cooling essential even after a reactor shutdown. Through this simulation, you'll gain a clear understanding of what went wrong and why the outcome was so different from other reactor types, such as Chernobyl’s RBMK design.

Perfect for anyone interested in nuclear physics or reactor safety! Watch to see how the smallest details in design and response can prevent—or lead to—nuclear disaster.

Songs used:

[Higgsinophysics]

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[Kingkoopa]

Something to add about Fukashima. After the earthquake, and the reactors scrammed, the emergency systems were cooling the reactors down. For some unknown reason, Reactor 1 was cooling down too fast, so the operators disabled the emergency cooling system. When the tsunami hit, it was disabled. If it had been enabled, the meltdown in Reactor 1 would have possibly occurred much more slowly.
Also, The backup battery systems in reactor 1 and 2 were flooded and failed, leading to increased speed of meltdown. The cooling pumps were also flooded and failed.

I think the biggest lesson learned in Fukashima is the importance of the protection of the backup systems. If the generators, batteries, and pumps had been either elevated in the building, or built into water-tight bunkers, there would have been zero issues. They would have kept running and cooling the scrammed reactors. The oversight was depending on the seawall. To be fair to the operators though, the seawall was built to a level well above what was thought to be the largest tsunami possible, so they depended on that to protect the plant.

The fact that the plant itself survived the earthquake with minimal damage is a testament to the designers. It was designed to withstand a magnitude 8 earthquake, and it withstood a magnitude 9, ten times more powerful, with minimal damage. But the tsunami was not expected to be so enormous.

[arforafro]

Funny how even the simulation reflects on how small the accident was in comparison to Chernobyl. Chernobyl simulation was almost a jumpscare with how quickly the particle count went out of control and turned the clicks into a very loud buzz. Here the click count increased and all the water vaporized but it did not reach the magnitude of the Chernobyl disaster.

[MultiSciGeek]

Ayy another video! Please keep making these, it really puts things into perspective. Like not just nuclear stuff, but science in general.

[Tjita]

Most people these days consider TMI to not have been a nuclear disaster (although the event did ruin the reactor itself), but rather a press disaster. The events were brought under control relatively quickly, but the press kept reporting it as an ongoing disaster.

[razy]

I hate how overblown three mile island was. Killed momentum in the US.

[guard]

The increased cancer rates associated with Fukushima and Three Mile Island are not from radiation release, they are from increased screening of people who were scared they would get cancer from radiation. When you look for cancer more, you find more cancer. One of the most ignored improvements in cancer treatment was getting better at deciding when to screen for cancer and what size of mass to consider cancerous.

It used to be that anything suspected of being cancer was treated aggressively, because cancer is so deadly. Then we realized that a lot of people when through a lot of hell to fight off things that weren't dangerous. Cancer is just a failure of the body to control its own growth - it is always fighting cancer as well, what we call cancer is when it fails. Recognizing this, we don't go after suspect masses nearly as fast anymore because it's better to wait it out a little - often these masses stop growing or even disappear, so if they were treated as cancer, that person would've suffered or possibly died during treatment for no benefit.

Likewise, it's actually better to treat cancer less seriously as you get really old, because when you're really old, you're a lot more likely to die from cancer treatment than from cancer, and you're a lot more likely to die of natural causes before cancer can grow enough to threaten your life. There's an age at which you shouldn't fight cancer at all, because you're going to die anyhow, and fighting it will just kill you.

Edit: Typo'd Fukushima.

[MultiSciGeek]

No but seriously last time I watched your Chernobyl video and was wondering about Fukushima, and here it is! Perfect!

[atmosphereventbutton]

Short and sweet, tells you pretty much everything you need to know about the accident in a simple manner. This video and the last one were super well made, great job!

[Everie]

Tip for audio mixing:

Use a De-esser filter to help with the "S" sounds to be more tamed and use a low-band pass filter on a 25% basis to enhance the quality of your audio

Your videos are extremely interesting and I know it takes a hell of a long time to edit them. So do this small change in your audio editing to perform even better at the commentary videos! (I like to know what's going on-screen, so your commentary is great for that)

[brownhorn]

Hey, great video! But I have a minor critique: Calling the TMI Incident "one of the worst reactor accidents" is a little bit misleading... It was a small accident blown out of proportion thanks to media sensationalization.

[AiOinc]

So glad you're doing more reactor videos. I loved the Chernobyl one.

[mr.hi_vevo]

If you haven't made a video on this already, have you considered showing simulations of modern, safer, or entirely safe reactors?

I would love to find out how they work, and it would be very useful for explaining to people how safe modern reactors are.

[justv]

The fact that TMI, the third worst nuclear accident in history, was "we shut it down lmao, " is a testament to how safe Nuclear really is.

[tomchambers]

YES another, I love these! It's such a clear and well executed explanation

[fieryweasel]

The first time I learned about the Zr+H2O reaction everything made sense, and I think it's unfortunately glossed over in many explanations (not this one). Zircaloy has the property of being transparent to most neutrons, but that water reaction can be problematic.

[k__k___]

Hey I really like these videos, the animations are brilliant - but a small tip if you like, the points you make would be easier to take in if you talked slower and took breaks. Sometimes you make a point, especially around 7:40 mark and you just speed into the next point. As a listener, I’d love time to take in what you’ve said before you move on.

[Wekuz]

Thank you for another banger video! Not usually that into physics, but your simulations and talking make it very interesting

[kindnuguz]

The Fukushima incident; I mean how much can you blame on design and overall use of fission? Wasn't there 2 or more waves that washed over the reactors?
But with all these incidents we've leaned priceless knowledge to improve design.
I still feel we haven't even started to use this technology to the fullest

[plewtoeee]

i just watched the chernobyl video yesterday, super excited to learn more about nuclear physics!