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The demon core was a 6.2-kilogram (14 lb), 89-millimetre-diameter (3.5 in) subcritical mass of plutonium that was involved in two criticality accidents. It briefly went supercritical in two separate accidents at the Los Alamos laboratory in 1945 and 1946, and resulted in the acute radiation poisoning and subsequent deaths of scientists Harry Daghlian and Louis Slotin. After these incidents the spherical plutonium core was referred to as the "demon core".
Igottalottacheese
Maybe it didn't help that they used a grade school ruler for measurements? :D
spiffariffic
When the core was finally used in a test, it had more explosive power than expected because the criticality charged it up.
humancoder
https://www.youtube.com/watch?v=hh89h8FxNhQ
ScootyPuffSr
Slotin's slot screwdriver screwup was the SECOND screwup with this core. They finally got rid of it as the pit in a nuclear bomb test.
Jallenallen
This is also a huge plot point in the Manhatten projects. Great comic book
Mortalitor
There was a TV show called Dark Matters: Twisted But True that told the story of one of them with reenactments.
TheBentPianist
"Tickling the dragons tail"
EyeHeartInk
Sounds like the plot from Heavy Metal.
fencerman
Yes, that is literally metal.
PewpShews
Cue "Die Eire von Satan."
akahata
*Eier
PewpShews
Err*
BoomaBB
Dark Matters: Twisted But True Season 2 Episode 4. It's a pretty good series.
satanscott
looks like a harmless bocce ball.
ghostcalib3r
Hey guys lets lower this neutron reflector with a screwdriver. If i fuck up we all die a painful death. Here goes!
UncleScarwasright
I used to work with Harry's brother, Eddie. Ironically, although a sweet man, Eddie was as intellectually limited as his brother was gifted
jumbosmooth
That ball of plutonium literally cost millions of dollars.
meccit
*billions of dollars to refine in the 1940s (worth ~$50m on its own)
jumbosmooth
That's right. It was a huge project.
Vaniel
Harry Daghlian didn't die though. He became irradiated, and eventually took out an entire alien species by accident.
Redbeard54
That part was badass
NerdN1
When it went super-critical, there was a flash of blue light. The guy at ground zero basically had all his DNA destroyed. >>
NerdN1
Funny thing about this sort of thing. You look fine for a while, but you are a deadman and will be gone in days.
That1guyshetoldyounottoworryabout
Ok. Burn me once, shame on you. Burn me twice, shame on me. If something fries a scientist, the second one is on you.
flacoloco
if anybody is interested there is a movie called "Fat Man and Little Boy" concerning this core
threepwood007
This was a really good movie too
Redbeard54
Thanks! I’m gonna give it a watch
pirre
@flacoloco I just watched it, thanks for the recommendation, I really enjoyed it!
zenmaster11
catflaps
I'm an idiot, so bear with me. Just being near that ball will kill you?
bigbootybandit
Normally no, it's 5% under critical mass so it's completely safe and not radioactive until something changes the density or mass of the ball
SpannerInTheWorx
No, closing the sphere that encapsulated the ball sets off a reaction that emitted a huge amt of radiation
bigbootybandit
This guy used a neutron reflector to see how close he could get the ball to going super critical and messed up.
KoRplussomeletters
"Not that close."
thxph
Upvoted for the perfect hyphenation.
HowCurious
It's actually a very interesting story. This doesn't do it justice by any means
Sholk7
Maybe don't let a screwdriver be the only thing between you and death
chrishallett83
That sounds a lot like you supporting safety regulations, you commie America-hating pinko commie bastard commie!
Bystandr
Would have taken not even a minute him to set that up with a clamp in a slide with a dial. Instead "Hey Ill just balance this bomb core with
Bystandr
my screwdriver while I observe the reaction from behind this lead screen." -Darwin award recipient
meccit
You beat me to it. Don't prop up fissile material with hand tools people.
JDJersey
That's what you get for tickling the dragon's tail.
CidColetti
That was going to be my line +1
YesThisIsPhteven
You missed the opportunity to say, "tickling the dragon's *balls*"
breothskin
He used the actual term.
YesThisIsPhteven
I know. I was just making a joke
NuVanDibe
Phteven pls
Strostkovy
This is why you don't drop neutron reflectors when working with barely subcritical masses.
angelGrinderSciFiLover
even i know that
sergeantapone
That's what mom always said
DrCreamandScream
That isn't how reflectors work. Reflecting the neutrons back into the core would make power go up, not down.
Strostkovy
If you drop it on the core, power goes way up. Such as in a criticality incident or something.
Strostkovy
The experiment was to measure radiation as the core approached critical by placing neutron reflectors around it. A block slipped on the core
blarglebrle
We used the data from those deaths and how quickly the deteriorated relative to their radiation exposure to extrapolate safe levels.
TheRicM
https://www.youtube.com/watch?v=c_GFzFqyaRc
nman10000
Similarly, we know how the human body reacts to vacuum thanks to Soyuz 11, where three men were exposed to space from an opened air vent.
bananamaniaman
Probably was made to look like an accident by someone else to obtain the figures.
Cgyachilles
Is there a link to that paper. I love reading about ars. Morbid I know
HostileNumber17
In short: How fast you die, and how close you can get .......before you die
BreakingRad
Makes you wonder, were those really accidents? We're those scientists merely lab rats?? *adjusts tinfoil hat
blarglebrle
Killing a Manhattan project scientist is like killing a cow to harvest a drop of milk. Compare monetary gains when it comes to conspiracy.
BreakingRad
It was just a joke bro
blarglebrle
Sorry too many tin foil hats on the Internet makes it difficult at times to differentiate the jokes from the serious nuts.+1 for both posts
Skinneralive
And then later we got https://en.m.wikipedia.org/wiki/Banana_equivalent_dose
PizzaAndSmiles
I honestly did not know this was a thing. Learning is neat
hispanicyankee
The Imgur-approved scale for measuring radiation
TwoHorndUnicorn
thats one of the reasons I love banana for scale
BeAGrape
You sound smart. What does supercritical mean? How did it kill those guys?
blarglebrle
Crypticsound tracked down the correct info before i could post.
DrCreamandScream
Sub, less neutrons produced per generation aka power goes down. Critical, equal neutrons per generation aka stable. Super, more neutrons per
DrCreamandScream
Super, more neutrons per generation aka power goes up. Generation being each reaction after the initial incident neutron.
BuskerJeff
It's like regular critical..But super...Physicists aren't really the best at naming stuff.
blarglebrle
In addition to crypticsound post on the supercritical part. The high dose of radiation disables the body's ability to heal.
TwoHorndUnicorn
supercritical means that the core is producing more neutrons than is necessary to maintain the fission process. basically its turned on high
spudcosmic
Just more than the critical mass.
spudcosmic
It killed them because critical reactions tend to throw a bunch of neutrons in every direction which kill you dead as your atoms get ionized
snipekill1997
It was made 5% below how big a chunk of plutonium (alone at normal temps and pressures) can be before for every neutron released triggers(1)
snipekill1997
the release of 1 neutron (N=1), criticality which is what nuclear reactors maintain at. They surrounded it with tungsten carbide bricks (2)
snipekill1997
in the first case, beryllium hemispheres in the second, that reflect neutrons so they could start getting close to criticality to see the(3)
snipekill1997
radiation released (still very low) to get a more exact calculation of the mass this happens at. Both times they messed up the procedure (4)
VarthGaydar
Well aren't you fancy.
blarglebrle
*adjusts monocle* thank you.
PerpetuallyPerplexedPlatypus
One monocle? What about two?
EVERYuserNAMEisTAKENthisISdumb
Glasses?
VarthGaydar
He's a cyclops and a researcher.
IsweartoGodLinda
Bionocle? Isn't that legos trademaek
PerpetuallyPerplexedPlatypus
duomonocle
FacemanPeck
I didn't know criticality was a word. Now I do.
Quipman
what? how? Where are you from?
MetaSomma
TIL you didn't know criticality is word
gigglebush
Right there with ya both
TwoHorndUnicorn
yep, when the reactor is producing enough neutrons to maintain a nuclear reaction, the reactor has gone critical
bob493
Well, hello fellow nuke. Hows the navy treating you? lol
dogsunpizza
sounds like a line from an action movie. "the reactor has gone critical"
TheShartParade
I actually said "the reactor is critical" today in the training simulator at my plant. It was excellent.
dogsunpizza
dope story brah
Givemeabreak432
Which actually means the reactor is running fine
dogsunpizza
don't tell me how to write my action movie script! lol
DrCreamandScream
Going critical is good. Hot rock make steam make spinny make electrical power. Ugg ugg
TwoHorndUnicorn
*spinny make boat go
bob493
*Spinny does both. Cream is an EM, and youre an ET Im assuming haha
bob493
and youre a surface electrician? haha
DrCreamandScream
Sub etn