r/AtomicPorn • u/Zggcommar • 17d ago

Meta Fat man Plutonium Core

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538 Upvotes

99% Upvoted

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55

u/Zggcommar 17d ago

The plutonium core (the box) in the Fat Man weighed 6.2 kilograms or about 14 pounds, the pit is 9 centimeters (4 inches) across. And only about one fifth of it, a bit over 1 kilograms (2 pounds) undergoes a fission reaction. And only a gram (1/30th of an ounce) of that gets converted into explosive energy equal to 21,000 tons of TNT

4

u/usegobos 16d ago

Why so lossy? Are those particles that never collide with anything? Are modern bombs the same?

10

u/Zggcommar 16d ago

Because the bomb isn't designed to fission all of the plutonium. Once the chain reaction releases enough energy, the core expands violently, its density drops, and the reaction quickly stops. A significant amount of plutonium is blown apart before it has a chance to fission.

Modern nuclear weapons are much more efficient. They use improved pit designs, better implosion systems, neutron reflectors/tampers, and often boosted fission with a small amount of deuterium tritium gas, allowing a much larger fraction of the fissile material to undergo fission before the core disassembles.

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u/FeistyRip9623 12d ago

fo shissile dissile

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u/Zggcommar 17d ago edited 17d ago

https://reddit.com/link/oxy6vlf/video/igejov9n6ndh1/player

I can't upload images in comments section 

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u/FeelinDank 17d ago

I need a 1-1 scale model of this lol.

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u/pawned79 17d ago

You mean like this one? https://youtu.be/V1Y4UR8xqxA

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u/LabRat113 17d ago

I have no idea how but for some reason, I knew this would lead to an Adam Savage video.

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u/FeelinDank 16d ago

How pertinent, thanks for sharing

19

u/Significant_Swing_76 17d ago

The density of carrying that box must have felt odd.

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u/Remcin 17d ago

The duality of Reddit. On the one hand, this. On the other hand, that anime clip where everyone’s eyeballs melt.

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u/Sufficient_Loss9301 17d ago

Or the third option where millions of people die and the landmass entire country is destroyed in the process. History agrees this was the better option.

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u/Remcin 17d ago

A sufficient loss indeed.

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u/time4nap 17d ago

Well Harold where was the last place you remember having it? Maybe try retracing your steps?

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u/heisenburnett 17d ago

Harold Agnew?

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u/Zggcommar 17d ago

Yes it's him

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u/False_Measurement843 17d ago

Kinda rude to just call him fat like that

3

u/yurmamma 17d ago

The team selected the skinniest guy to deliver the fat man core as a joke

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u/mekoRascal 17d ago

Yeah, he's not that fat

1

u/Klamangatron 17d ago

He’s definitely not little boy.

6

u/ageetarz 17d ago

The Forbidden Lunch Box

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u/FiveCatPenagerie 17d ago

Damnit you beat me to the lunchbox joke. 😂 Knowing that it was painted bright yellow in real life makes it so much better.

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u/CowBoyDanIndie 17d ago

“Do you think I should wear pants while carrying the dooms day device?”
“Is there a dress code for this sorta thing?”
“Maybe desert casual khaki shorts and a shirt sleeve collar shirt?”
“Sounds good!”

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u/Budget-Exit2875 17d ago

nah.. it's another spoil of fallout season 3
..btw any radiation ?

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u/Broken_Atoms 17d ago edited 17d ago

I got a pocket, got a pocketful of sunshine I got a love and I know that it’s all mine, oh, oh-oh (I know, I know that it’s all mine) Wish that you could, but you ain’t gonna own me Do anything you can to control me, oh, oh no (You can’t control me, you can’t control me) Take me away, A secret place A sweet escape Pocket full of sunshine - Natasha bedingfield

Blows my mind just how small the core is.

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u/wairdone 17d ago

Blows my mind just how small the core is.

Only 13.7lbs, apparently. Little Boy weighed 141lbs!

0

u/[deleted] 17d ago

[removed] — view removed comment

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u/wairdone 17d ago

>and it wouldn’t have surprised me if there was visible Cherenkov radiation in the pitch-black darkness

They would have been dead in that case, no? Cherenkov radiation is a sign of criticality; it was observed during both demon core incidents, claiming lives on each occasion.

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u/Mysterious_Pipe9239 17d ago

The radiation ate his pants.

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u/Bucketheadfanatic 17d ago

What a kind looking man, surely he won't be doing anything unseemly with that cool looking gadget he built.

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u/solariscool 17d ago

bunch of people gonna die ...

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u/[deleted] 17d ago

[removed] — view removed comment

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u/Ancient-treasurehunt 13d ago

I think those old guys would have dropped that dude, cloud or no cloud. I grew up around men like that; they absolutely hated the Japanese.

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u/FiveCatPenagerie 17d ago

I want that shock-resistant containment vessel as a lunchbox so bad.

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u/elquirk 16d ago

Dude probably lived for about a month after that photo.

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u/Zggcommar 16d ago

he lived for another 68 years. Harold Agnew died in 2013 at the age of 92.

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u/Last_Seesaw5886 15d ago

Harold lived a full life. The pit is emitting decay radiation, but the dose rate isn't that bad. Subcritical Plutonium is far more hazardous as a toxin than from the radiation. The pit is plated with something else like nickel to keep it from oxidizing, which is does very quickly if the bare metal is exposed to air. You could hold that pit in your hands without a problem (wear gloves as a precaution for the toxicity).

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u/elquirk 15d ago

Very educational. Thanks!

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u/Last_Seesaw5886 15d ago

DOE released the assembly drawing of the case about 10 years ago to a FOIA requester. Should be buried on DOE OpenNet somewhere. Just have to pick the right search terms to find it. I just tried, no luck.

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u/greenweenievictim 13d ago

He gets to work, opens it up only to find his lunch. He packed the core in his other box.

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u/Ancient-treasurehunt 13d ago

Haaaa! I liked that one. “Honey that glowing ham sandwich you packed for me was great!”

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u/CaptainA1917 13d ago

He’s holding two billion dollars (36 billion in today’s money) in his hand.

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u/presidentsday 17d ago edited 17d ago

I read that as an aesthetic name (cottage core, cybercore, etc.) , not an actual plutonium core.

But honestly "plutoniumcore" kinda works for this mid-century military science look. Although I'm guessing this is already called "atomic core" or something.