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The Demon Core (The Horror)
X ^ | 06/29/2025 | Yama

Posted on 06/29/2025 6:16:51 PM PDT by Az Joe

This harrowing incident on May 21, 1946, remains one of the most infamous accidents in the history of nuclear research, a fatal moment of human error and hubris known as the "demon core" incident.


TOPICS: History; Miscellaneous; Science
KEYWORDS: demon; nuclear; oops; paranoia; radiationtruth
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To: Az Joe

Very.


21 posted on 06/29/2025 7:33:46 PM PDT by No name given ( Anonymous is who you’ll know me as)
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To: Ciaphas Cain

“What was he thinking, using a flathead screwdriver to keep the core halves separated?”

It was a stupid act but it had a purpose.

He could vary the reactivity within limits by rotating the blade.

Quicker and easier than varying the shims originally used.

He was know for taking risky shortcuts.


22 posted on 06/29/2025 7:40:34 PM PDT by TexasGator (..D\ logo About Issues Projects Products Connect Subscribe Invest June 19, 2025 | Insight '1-1111 -)
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To: Az Joe

I worked in radiation effects for over 20 years. Some facilities were capable of producing 1200 Rads/sec. I had two 50’s vintage x-ray machines in my lab (real frankenstein stuff) and had less than 20 mrem on my personal dosimeters in all that time.

It’s just careful planning and procedure. A scientist is not a test pioly.


23 posted on 06/29/2025 7:40:50 PM PDT by Tijeras_Slim
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To: Az Joe

Slotin was actually the second person to be killed by a mishap with this core. The first was a man named Harry Daghlian.

https://en.wikipedia.org/wiki/Demon_core


24 posted on 06/29/2025 7:41:05 PM PDT by Coronal
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To: ProtectOurFreedom

Old school hard core, I worked with guys like that who did atmospheric testing.


25 posted on 06/29/2025 7:43:31 PM PDT by Tijeras_Slim
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To: TexasGator

We Heard it First Here
On FREEREPUBLIC!_


26 posted on 06/29/2025 7:44:04 PM PDT by Big Red Badger (ALL Things Will be Revealed !)
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To: Coronal

Yeah. Turns out it’s not such a great idea to leave a slightly sub-critical spherical hunk of weapons-grade plutonium laying around where young atomic geeks can play with it.


27 posted on 06/29/2025 7:51:30 PM PDT by Steely Tom ([Voter Fraud] == [Civil War])
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To: Big Red Badger

“We Heard it First Here
On FREEREPUBLIC!_”

Ugh. Now we all will be getting visits from the FBI. JR is not going to like having to turn in our emails and ISP’s.


28 posted on 06/29/2025 7:53:05 PM PDT by TexasGator (i-D\ logo About Issues Projects Products Connect Subscribe Invest June 19, 2025 | Insight '1-1111 -)
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To: ebshumidors

Yes.
Hiroshima and Nagasaki survivors were very well studied.
Lot of them got cancers. In hysterical, no nuke, hungry lawyer environment, all of those cancers were from the radiation.
But a lot of people in general population are also getting cancer!
The study compared the survivors to the general population and found “Statistically significant, about 1% rise of cancers” in A-bomb survivors.
Calculations resulted with estimated 300+ survivors getting and dying of cancer from the explosions!
Note; those are the deaths attributable to radiation.
Most people in Hiroshima died of the explosion, mostly from the heat wave. Many just evaporated! But if you survived the explosion, your chances of long term harmful effects from the exposure were small, a lot smaller than the media would suggest.

There are about 300 additional documented deaths from radiation due to various accidents, like above (including Chernobyl ~50 deaths). Surprisingly to me, lot of them were accidents involving radioactive medical instruments.

Then, there were some (likely, guessed) accidents in old Soviet Union, North Korea and China. These accidents were suppressed and number of victims is unknown.
Long term effects of various exposures are disputed, but, realistically, from the analogy to the the Hiroshima study, they are estimated to be pretty small.


29 posted on 06/29/2025 7:59:09 PM PDT by AZJeep (sane )
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To: Tijeras_Slim

It’s amazing my uncle did all that plutonium machining for H Bombs yet lived until 99 years old!

He also ran a uranium enrichment shift at Oak Ridge National Lab on the Manhattan project.

He got so fed up with making killing weapons that he went back to school and got his DDS and was a very successful dentist and orthodontist.


30 posted on 06/29/2025 8:04:35 PM PDT by ProtectOurFreedom (“Diversity is our Strength” just doesn’t carry the same message as “Death from Above”)
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To: Coronal

Wild times


31 posted on 06/29/2025 8:12:09 PM PDT by Az Joe (Live free or die)
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To: Ciaphas Cain
Exactly. A flathead screwdriver isn't worth a damn. Should have used a Robertson or Torx! 😀

32 posted on 06/29/2025 8:13:18 PM PDT by Governor Dinwiddie ( O give thanks unto the Lord, for He is gracious, and His mercy endures forever. — Psalm 106)
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To: darth

If the runway was turned into a car lot…

…wouldn’t it have been found and dealt with?


33 posted on 06/29/2025 8:13:38 PM PDT by BradyLS (DO NOT FEED THE BEARS!)
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To: ProtectOurFreedom
#30: "he went back to school and got his DDS and was a very successful dentist"

At least he didn't have to buy an x-ray machine.

34 posted on 06/29/2025 8:19:52 PM PDT by Governor Dinwiddie ( O give thanks unto the Lord, for He is gracious, and His mercy endures forever. — Psalm 106)
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To: AZJeep

Of the flip side of radiation exposure, see the story of Albert Stevens, house painter from Ohio and the most radioactive person ever!

https://en.wikipedia.org/wiki/Albert_Stevens

He was mistakenly injected massive dose of radioactive plutonium, but lived healthy life, with no apparent effects of radiation exposure, ever.
Stevens died of heart disease some 20 years later, having accumulated an effective radiation dose of 64 Sv (6400 rem) over that period, i.e. an average of 3 Sv per year or 350 μSv/h.

Slotin got only like 10 Sv! 6x less, but in an instant!

The theory of accumulative radiation is more-less proven wrong, there is great evidence that body heal itself over time from the exposure. Stevens is the best example! He would not survived 64Sv dose given in single short exposure!


35 posted on 06/29/2025 8:22:22 PM PDT by AZJeep (sane )
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To: AZJeep

I had no idea. Thanks.


36 posted on 06/29/2025 8:27:23 PM PDT by ebshumidors ( )
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To: Az Joe

There was a previous criticality incident with the “Demon core” on August 21, 1945 Harry Dahlian was messing with the core and induced an energy excursion killing himself and injuring others. After the Slotin excursion the core was melted down and used in other weapons.


37 posted on 06/29/2025 8:33:22 PM PDT by VTenigma (Conspiracy theory is the new "spoiler alert")
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To: Governor Dinwiddie

LOL! I always wondered about that eerie bluish glow about him!


38 posted on 06/29/2025 8:34:41 PM PDT by ProtectOurFreedom (“Diversity is our Strength” just doesn’t carry the same message as “Death from Above”)
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To: VTenigma

weird, deadly science


39 posted on 06/29/2025 8:36:41 PM PDT by Az Joe (Live free or die)
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To: Ciaphas Cain

He was a smart guy, but he became complacent. See this a lot, factory or industrial settings, and the military. There’s the prescribed “book way” and people working long hours sometimes take short cuts. Managers will look the other way. “Everybody does it”. Etc.

There were actually TWO different deadly incidents with the “demon core” halves, Louis, and some other guy a couple years later. By all accounts radiation poisoning is not a good way to go.


40 posted on 06/29/2025 8:56:03 PM PDT by Freedom4US
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