The first nuclear reactor

[steve_bank]

I read an account of when the first nuclear reactor went critical underneath a stadium at University Of Chicago.

In the picture someone was stranding on top of the graphite pile with a bucket of something as control rods were pulled.

Nothing ventured nothing gained. If they understated the U of C may have been the first nuclear catastrophe. They had no simulations and no computers. As rods were pulled the scientists watched gauges, made slide rule calculations, and went a little farther.


https://en.wikipedia.org/wiki/Chicago_Pile-1#Construction

The next day, 2 December 1942, everybody assembled for the experiment. There were 49 scientists present.[92] Although most of the S-1 Executive Committee was in Chicago, only Crawford Greenewalt was present, at Compton's invitation.[93] Other dignitaries present included Szilard, Wigner and Spedding.[92] Fermi, Compton, Anderson and Zinn gathered around the controls on the balcony, which was originally intended as a viewing platform.[94] Samuel Allison stood ready with a bucket of concentrated cadmium nitride, which he was to throw over the pile in the event of an emergency. The startup began at 09:54. Walter Zinn removed the zip, the emergency control rod, and secured it.[94][95] Norman Hilberry stood ready with an axe to cut the scram line, which would allow the zip to fall under the influence of gravity.[95][96] While Leona Woods called out the count from the boron trifluoride detector in a loud voice, George Weil, the only one on the floor, withdrew all but one of the control rods. At 10:37 Fermi ordered Weil to remove all but 13 feet (4.0 m) of the last control rod. Weil withdrew it 6 inches (15 cm) at a time, with measurements being taken at each step.[94][95]

The process was abruptly halted by the automatic control rod reinserting itself, due to its trip level being set too low.[97] At 11:25, Fermi ordered the control rods reinserted. He then announced that it was lunch time.[94]

The experiment resumed at 14:00.[94] Weil worked the final control rod while Fermi carefully monitored the neutron activity. Fermi announced that the pile had gone critical (reached a self-sustaining reaction) at 15:25. Fermi switched the scale on the recorder to accommodate the rapidly increasing electrical current from the boron trifluoride detector. He wanted to test the control circuits, but after 28 minutes, the alarm bells went off to notify everyone that the neutron flux had passed the preset safety level, and he ordered Zinn to release the zip. The reaction rapidly halted.[98][95] The pile had run for about 4.5 minutes at about 0.5 watts.[99] Wigner opened a bottle of Chianti, which they drank from paper cups.[100]

Compton notified Conant by telephone. The conversation was in an impromptu code:


Compton: The Italian navigator has landed in the New World.
Conant: How were the natives?
Compton: Very friendly.[101]

 

[skepticalbip]

That was the first man made fission reactor. Nature beat us to it by a couple billion years.

https://blogs.scientificamerican.com/guest-blog/natures-nuclear-reactors-the-2-billion-year-old-natural-fission-reactors-in-gabon-western-africa/

Two billion years ago— eons before humans developed the first commercial nuclear power plants in the 1950s— seventeen natural nuclear fission reactors operated in what is today known as Gabon in Western Africa [Figures 1 and 2]. The energy produced by these natural nuclear reactors was modest. The average power output of the Gabon reactors was about 100 kilowatts, which would power about 1,000 lightbulbs. As a comparison, commercial pressurized boiling water reactor nuclear power plants produce about 1,000 megawatts, which would power about ten million lightbulbs.

Despite their modest power output, the Gabon nuclear reactors are remarkable because they spontaneously began operating around two billion years ago, and they continued to operate in a stable manner for up to one million years. Further, at the Gabon reactors many of the radioactive products of the nuclear fission have been safely contained for two billion years, providing evidence that long-term geologic storage of nuclear waste is feasible.

........snip........

 

[Shake]

As I recall, Richard Rhodes' The Making of the Atomic Bomb discussed the U of C pile as part of its historical presentation leading up to bomb manufacture. It is a very good read.

 

[steve_bank]

It was part of the Manhattan Project

Well, the sun is a natural fusion reactor.

Were those natural nuclear piles able to generate electricity?

 

[skepticalbip]

Were those natural nuclear piles able to generate electricity?

Nope, like the pile in Chicago, there is no evidence that there was an electric generator involved. But while the Chicago pile ran for about 4.5 minutes at about 0.5 watts, each natural reactor in Gabon ran for about a million years at about 100 Kilowatts.

 

[steve_bank]

Were those natural nuclear piles able to generate electricity?

Nope, like the pile in Chicago, there is no evidence that there was an electric generator involved. But while the Chicago pile ran for about 4.5 minutes at about 0.5 watts, each natural reactor in Gabon ran for about a million years at about 100 Kilowatts.

I surrender, you win.