The Demon Core - Nuclear Stability and Critical Mass

Now a days we see exponential growth everywhere. One of my favorite stories I've learned about exponential growth is the story of the Demon Core. A nuclear warhead which managed to kill negligent scientists without ever being detonated. But why did the Demon Core exist in the first place?

Sources:

[logicplague]

"Well, that does it"
- Slotin, immediately after the incident

edit: you're right, corrected

[ZimoNitrome]

Dang, I thought this was gonna be a history lesson but instead gave some very intuitive explainations of particle physics concepts. Great vid!

[somniad]

"...died 9 days later in agony due to..."
*comical pained noise*

[G-Money]

You should mention that Slotin incident is actually the second supercriticality incident with this core. Harry Daghlian was killed a year earlier in basically the same way.

[AdamTheJensen]

I've heard about the demon core so many times, but this video is by far the best I've seen. I never realized that "critical mass" was more than just a literal constant mass. The factors that affect it make so much sense. Thank you for an excellent explanation!

[dzfz]

I’m a university lecturer and honestly I’m glad to see guys like you putting us out of business. University sector run for profit without keeping up to date and relevant is a crime. Glad to see your excellent work here!

[sewrgator]

0:15 this animation is pure nightmare fuel

[HailAnts]

In the Slotin accident, he wasn’t supposed to be using just wooden wedges. The top beryllium sphere was supposed to be attached to a screw-type lowering mechanism.

However it was kind of a hassle to setup, so he just used a screwdriver. A week or two earlier Enrico Fermi himself witnessed Slotin doing the test like that and told him ‘You’ll be dead within a year if you keep doing it that way’.

Oopsie-daisies!

[pikerpoler]

This gave me chills, he must have known he is gonna die, when it dropped down.

[lemeres]

This was part of a demonstration for his replacement. they had wanted to replace him for a long time, but he was pretty much the only guy in the world trained for his job. As you can guess, this guy was checked the hell out during this.
So the lesson became pretty simple, yet effective: "Rule #1- Don't do this".

[alanboro]

You need to go big man, your content is so top notch

[brandonmtb]

The high school books never covered the smaller particles of neutrons and protons so it was cool to get a better understanding of the strong force

[mrRufffnTumble]

There was a movie that recreated this event, watching louie realize his fate was sealed was really terrible, and even worse was watching his condition deteriorate in those 9 days. Truly has to be one of the most terrible ways to die, slow and incredibly painful with no hope of survival

[timg]

This is the best explanation I've ever seen for why large nuclei are unstable and where nuclear radiation comes from. This is such an underrated channel.

[jamestouchette]

I'm 40, veteran of 9 years, raised by a dyed-in-the-wool Marine...I tend to think of myself as a pretty jaded and difficult-to-rattle individual.

But when I got to the part about the screwdriver slipping and him being instantly lethally dosed with radiation, realizing how narrow a margin they were playing with, I genuinely shuddered.

[akshitsahu]

Your videos are some of the best on YouTube for explaining things. Period.

[kwas]

This is the best explanation of this topic I've ever heard. I finally understand what Slotin was doing, and why this was a problem. I've subscribed, you need more subscribers!

[LouisE-mplx]

I never understood why they would use this setup, where the top half is being lowered onto it. You’re working against gravity, if you slip once, it’s over. As we saw in the video.

Why would they not fix the top half in place, and then have the bottom half on a lab jack or something, and then raise that up toward the core? That way if you accidentally slip, gravity is on your side and pulls the bottom half away from the core.

[vinny]

Small nitpick: it's not a nuclear warhead, it's the core from a nuclear warhead. The actual warhead also contains a sh*tload of explosives to get the core to go boom.

0:35 They are not checking if it is still ready to explode. They don't do that. A near-critical core will remain read to explode for the next several thousand years.
What they are doing is testing what it takes to get the core to go critical. Yes, going critical is part of what happens when it explodes, but a core can happily remain near-critical for a long time and never explode. This is exactly what happens in nuclear powerplants; they let the fuel go critical and control the situation with controlrods.

Also; the core was designed to go into a bomb, where it's sole purpose was to go boom. They have to create it near-criticalotherwise getting it to go supercritical (boom) gets too difficult.

[smakkacowtherealone]

I like how this is a video about a nuclear accident and the life lesson is to not overwork yourself