The Demon Core was a sphere of plutonium intended to be used as part of a nuclear bomb dropped on Japan. It wasn’t used for this purpose, and instead nuclear physicists used it in various experiments. Two of which involved approaching criticality.
One experiment involved stacking bricks made of some neutron reflecting material, like beryllium or something, around the core. Reflecting neutrons back at the plutonium would cause more fission events to occur; if it hits a certain threshold called criticality it it will release a considerable amount of radiation and heat. The goal was to get close to, but not exceed, that limit. The scientist was about to place one more brick when his instruments told him it would go critical if the brick was placed, so he started to back off…and dropped the brick.
The core went critical, releasing a wave of heat and a blast of dazzling blue light. Thinking quickly, the scientist smacked the brick away with his hand. He spent the next couple weeks dying of radiation sickness.
A short time later, another scientist started a similar experiment, this time enclosing the core in two half-spherical metal shells. If the core was completely surrounded by the shells, it would go critical. He used the blade of a flathead screwdriver to almost, but not quite, close the shells. Then the screwdriver slipped and the shells fully closed.
The core went critical, releasing a wave of heat and a blast of blinding blue light. Thinking quickly, the scientist smacked the upper shell away with his hand. He spent the next couple weeks dying of radiation sickness.
Decades later, youtube hair and beard model Kyle Hill released a video detailing this story, and it has since become something of a sensation on the internet. Images of the demon core in its “closing the shells” configuration is often used as shorthand for something that is exceedingly needlessly reckless. Some of the humor comes from if ya know, ya know, some of it is based in the justaposition of teh high intelligence required to do nuclear physics, with the negligent stupidity of putting nothing between you and a long ugly painful death but the blade of a screwdriver.
Recall the core was supposed to be the business end of a nuclear bomb, it was supposed to be near criticality so that a nuclear explosion could be triggered. They were measuring just how close to criticality it was. I don’t fully understand why they were doing that; could be anything from refining nuclear bomb design to developing safety procedures, aka “Don’t store this next to this much beryllium.”
In the first case, Harry Doghlian was stacking bricks. The instruments read he was close to criticality as he started to place one last brick, so he had achieved the goal of the experiment, and then he dropped the brick. Doghlian died from failure of imagination, his experimental apparatus did not account for clumsiness. Also in the room was a military private named Robert Hemmerly acting as a security guard, who was also exposed and died 33 years later from leukemia.
In the second case, Louis Slotin was closing a hemispheric shell. As designed, there were supposed to be shims that wouldn’t let the shell completely close. He removed these shims and instead used the blade of a screwdriver. Which slipped. Once again, the test apparatus did not account for clumsiness…or it did, but the safety measures were defeated.
Slotin was apparently prone to bravado, he had done this test/demonstration about a dozen times for small crowds; there were seven other people in the room with him including someone looking over his shoulder. While part of the scientific method is repeating experiments, I’m not convinced he wasn’t just showing off.
In the human factors chapter of flight school we teach about the five hazardous attitudes. Slotin demonstrated three of the five:
Anti-authority. The removal of the shims was not authorized, but he did it anyway.
Macho. Most accounts I’ve read make a point to mention the blue jeans and snakeskin boots he wore, suggesting a cowboy attitude.
Invulnerability. Slotin knew Doghlian personally and had visited Doghlian in the hospital as he lay literally falling apart at the cellular level…and then went to work to take the safety shims out of his radiation test apparatus. What kind of man does that? One who thinks it can’t happen to him. How’d that work out?
I’ll leave it as an exercise to the reader to look up what the other two hazardous attitudes are.
Further experiments with the demon core were done via robotic remote control with personnel a quarter mile away. Somebody finally said “Hey, maybe we shouldn’t be doing criticality experiments with our bare hands.”
Yeah, the showing off is what I was getting at. The first experiment seemed more like an experiment and an accident but the demonstrations with the screwdriver seemed more like someone doing pull-ups over a fatal drop just to show how badass they are and accidentally landing on other people on the bottom when he slipped.
Thanks for the in depth response though, this gives more context to this than I’ve had before.
And just guessing on the other two attitudes before looking anything up (haha maybe wanting to challenge my intuition like this instead of just looking it up is one), one is probably related to laziness (eg assuming something is fine and doesn’t need to be checked when going through the pre flight checklist). And maybe the other is being too trusting or not assertive enough (eg colleague says something is OK, you don’t fully believe them but don’t challenge them on it). Am I close?
Both of your guesses I would put into Resignation. “I can’t do anything about it, so why bother?” Why bother checking the fuel for contaminants, it’s always clean anyway. Why bother standing up to the aircraft owner, I’m gonna have to fly the mission anyway whether or not I think it’s safe.
The other is Impulsivity, the tendency to do things at the spur of the moment without thinking anything through. Jumping into the plane to fly off somewhere without planning the flight, reacting to a problem by instantly doing the first thing that comes to mind instead of working the problem, etc.
The Demon Core was a sphere of plutonium intended to be used as part of a nuclear bomb dropped on Japan. It wasn’t used for this purpose, and instead nuclear physicists used it in various experiments. Two of which involved approaching criticality.
One experiment involved stacking bricks made of some neutron reflecting material, like beryllium or something, around the core. Reflecting neutrons back at the plutonium would cause more fission events to occur; if it hits a certain threshold called criticality it it will release a considerable amount of radiation and heat. The goal was to get close to, but not exceed, that limit. The scientist was about to place one more brick when his instruments told him it would go critical if the brick was placed, so he started to back off…and dropped the brick.
The core went critical, releasing a wave of heat and a blast of dazzling blue light. Thinking quickly, the scientist smacked the brick away with his hand. He spent the next couple weeks dying of radiation sickness.
A short time later, another scientist started a similar experiment, this time enclosing the core in two half-spherical metal shells. If the core was completely surrounded by the shells, it would go critical. He used the blade of a flathead screwdriver to almost, but not quite, close the shells. Then the screwdriver slipped and the shells fully closed.
The core went critical, releasing a wave of heat and a blast of blinding blue light. Thinking quickly, the scientist smacked the upper shell away with his hand. He spent the next couple weeks dying of radiation sickness.
Decades later, youtube hair and beard model Kyle Hill released a video detailing this story, and it has since become something of a sensation on the internet. Images of the demon core in its “closing the shells” configuration is often used as shorthand for something that is exceedingly needlessly reckless. Some of the humor comes from if ya know, ya know, some of it is based in the justaposition of teh high intelligence required to do nuclear physics, with the negligent stupidity of putting nothing between you and a long ugly painful death but the blade of a screwdriver.
What was the point of these approaching criticality experiments anyways?
Recall the core was supposed to be the business end of a nuclear bomb, it was supposed to be near criticality so that a nuclear explosion could be triggered. They were measuring just how close to criticality it was. I don’t fully understand why they were doing that; could be anything from refining nuclear bomb design to developing safety procedures, aka “Don’t store this next to this much beryllium.”
In the first case, Harry Doghlian was stacking bricks. The instruments read he was close to criticality as he started to place one last brick, so he had achieved the goal of the experiment, and then he dropped the brick. Doghlian died from failure of imagination, his experimental apparatus did not account for clumsiness. Also in the room was a military private named Robert Hemmerly acting as a security guard, who was also exposed and died 33 years later from leukemia.
In the second case, Louis Slotin was closing a hemispheric shell. As designed, there were supposed to be shims that wouldn’t let the shell completely close. He removed these shims and instead used the blade of a screwdriver. Which slipped. Once again, the test apparatus did not account for clumsiness…or it did, but the safety measures were defeated.
Slotin was apparently prone to bravado, he had done this test/demonstration about a dozen times for small crowds; there were seven other people in the room with him including someone looking over his shoulder. While part of the scientific method is repeating experiments, I’m not convinced he wasn’t just showing off.
In the human factors chapter of flight school we teach about the five hazardous attitudes. Slotin demonstrated three of the five:
Anti-authority. The removal of the shims was not authorized, but he did it anyway.
Macho. Most accounts I’ve read make a point to mention the blue jeans and snakeskin boots he wore, suggesting a cowboy attitude.
Invulnerability. Slotin knew Doghlian personally and had visited Doghlian in the hospital as he lay literally falling apart at the cellular level…and then went to work to take the safety shims out of his radiation test apparatus. What kind of man does that? One who thinks it can’t happen to him. How’d that work out?
I’ll leave it as an exercise to the reader to look up what the other two hazardous attitudes are.
Further experiments with the demon core were done via robotic remote control with personnel a quarter mile away. Somebody finally said “Hey, maybe we shouldn’t be doing criticality experiments with our bare hands.”
Yeah, the showing off is what I was getting at. The first experiment seemed more like an experiment and an accident but the demonstrations with the screwdriver seemed more like someone doing pull-ups over a fatal drop just to show how badass they are and accidentally landing on other people on the bottom when he slipped.
Thanks for the in depth response though, this gives more context to this than I’ve had before.
And just guessing on the other two attitudes before looking anything up (haha maybe wanting to challenge my intuition like this instead of just looking it up is one), one is probably related to laziness (eg assuming something is fine and doesn’t need to be checked when going through the pre flight checklist). And maybe the other is being too trusting or not assertive enough (eg colleague says something is OK, you don’t fully believe them but don’t challenge them on it). Am I close?
Both of your guesses I would put into Resignation. “I can’t do anything about it, so why bother?” Why bother checking the fuel for contaminants, it’s always clean anyway. Why bother standing up to the aircraft owner, I’m gonna have to fly the mission anyway whether or not I think it’s safe.
The other is Impulsivity, the tendency to do things at the spur of the moment without thinking anything through. Jumping into the plane to fly off somewhere without planning the flight, reacting to a problem by instantly doing the first thing that comes to mind instead of working the problem, etc.