Sunday, July 15, 2012

The Demon Core

This is it, the infamous Demon Core.   So what the devil (pardon the pun) is a demon core?   It is the plutonium core of a nuclear bomb.   There were originally two types of atomic bombs:  uranium and plutonium.   The uranium atomic bomb was relatively simple.   But the plutonium was more complicated and difficult.   They ran experiments on this plutonium core.   So why call is the "demon core"?   Why, because two scientists at  Los Alamos were killed by the very same core.   Tragic deaths.   The first to die was Harry Daghlian.    When you see a picture of the individual it hits home a little bit harder.   We aren't just talking about a story of a radiation accident, but an individual.   And so young.

On August 21, 1945 he was performing an experiment with this plutonium core by stacking bricks made of tungsten carbide around the core.   These bricks made a small chain reaction start and as he stacked more bricks around the core the chain reaction increased in intensity.   When he got to the last brick he realized that if he put it on top of the stack of bricks surrounding the demon core that it would go supercritical (a bad thing).   He decided not to put the last brick of titanium carbide and as he raised the brick away from the demon core it slipped and fell from his hand.   Where did it land?   Yep, right on top of the pile of bricks.   The absolutely worst place that it could land.   The demon core went supercritical emitting massive radiation (neutrons).   Harry Daghlian reached down to the pile of bricks and started pulling some of the bricks away from the pile to stop the chain reaction.    He was successful but he had gotten a lethal dose of radiation.   He died 25 days later from radiation poisoning on September 24, 1945 at the age of 24.
      But the Demon Core wasn't finished yet.  Another scientist at Los Alamos by the name of Louis Slotin was also killed by the Demon Core.

On May 21, 1946 he was doing experiments causing a small chain reaction by lowering a beryllium shell over the plutonium core.   He used a screwdriver to keep the beryllium shell from coming completely down on top of the plutonium core (that would be bad).   Scientists referred to this as "tickling the dragon's tail" because it was so dangerous.   As he proceeded with the experiment the screwdriver slipped and the beryllium shell came down completely on top of the plutonium core.

There was a flash of blue light and a wave of heat.    He yanked the beryllium shell away from the core but it was too late.    The demon core had struck again and Louis Slotin died 9 days later on May 30, 1946 at the age of 35 from radiation poisoning.
        Whatever happened to this Demon Core?   It was used in the atomic bomb test codenamed Able of the Crossroads series of Atomic bomb tests at Bikini Island in the south pacific ocean.

And so the Demon Core that had killed two scientists had come to an end.   It just seems incredible that this one plutonium core killed two scientists less than a year apart.   By the way, the Demon Core had an explosive power equivalent to 23,000 tons of TNT.   This is pretty close to the Fat Man bomb dropped on Nagasaki which had an explosive power of 21,000 tons of TNT.   In closing, Demon Core seems to be an appropriate name to call this plutonium core for an atomic bomb.    Let me know your thoughts on this blog are, I would be interested in what you think.   Lew


dragonetti said...
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dragonetti said...

Wouldn't it have killed just about anyone, though, since it must have been highly radioactive and yet all these scientists were working with it in close proximity without any kind of protection? Today, I imagine experiments of this kind would be done remotely, using robotics so that no human has to get anywhere near it, like the storage place for decommissioned warheads. I read there are thousands of these, kept in one facility, stored in lead-lined steel barrels. they need to be moved and rotated, apparently, so all the work is done by robots, programmed or controlled by humans many miles away.

Lew said...

The scientist standing closest to the plutonium core when the accient occured absorbed enough of the radiation to save the lives of the others in the room. Of course the scientist standing closest was the one to die in both accidents. The problem is that a person can't see, smell, or usually feel radiation and so becomes casual about the hazards. The scientists were racing the Germans to develop the atomic bomb before the Germans did. Thank goodness we won the race. Today work around radiation is much more careful and dragonetti was right about the use of robotics. Lew