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This is NOT the case, even if the mine was 100% Uranium this would not happen, at least not today. As someone else pointed out, the world did have a natural re

This is NOT the case, even if the mine was 100% Uranium this would not happen, at least not today. As someone else pointed out, the world did have a natural reactor, Oklo, Gabon 1.5 billion years ago. When Uranium is refined, they are enriching the U235 vs U238. The ratio is too low today to sustain any natural reactors, but 1.5 billion years ago this wasnt the case.

sandworm101 6y ago
Not the case on day-1, but an open pit of 65% uranium isn't a typical lab experiment. Add some rain, some evaporation, some oxygen, countless other micro effects, and after a while you will get localized concentrations of U235. Then things start to get interesting as the fertile U238 is changed into other things. I'm not saying that that actually happened, just that a hypothetical multi-kiloton pile of 65% natural uranium isn't a neutral pile of sand.
- credit_guy 6y ago
  Evaporation, oxygen and any number of other effects won't change the ratio of U235 and U238. Those isotopes are chemically identical. The only way they are different is by their different atomic mass, i.e. their gravitational effects. And since the atomic mass is different by only about 1%, even the gravitational effects are almost identical. So U235 constitutes between 0.71% and 0.72% of the Uranium everywhere in the world.
- kenned3 6y ago
  Exactly as the other guy posted. U235 doesnt do anything "interesting" until you get it to around 3%. Due to somewhat obvious reasons (not a lot of net-new uranium being formed, and the half life is fairly stable), the Uranium concentration is pretty uniform around the world and is something like: uranium-235 0.720% uranium-238 99.275% uranium-234 0.006% Evaporation and other factors wont change this, it hasnt changed this ratio in the muti-billion years Uranium has been on earth. What does change this is the half life of U235. U235 wont naturally 'accumulate', it doesnt move around in rock to form higher concentrations, it is generally 0.720 everywhere. The natural reactor ran becaues back then there was simply more U235 (half life 700 million years) vs the half life of U238 (4.5 billion years) No Hypothetical examples needed. Open pit mines wont do anything 'interesting' unless you can either go back in time, or reverse the U235 Decay and then add water and you will probably get something like what took place at Gabon.

sandworm101 6y ago

Not the case on day-1, but an open pit of 65% uranium isn't a typical lab experiment. Add some rain, some evaporation, some oxygen, countless other micro effects, and after a while you will get localized concentrations of U235. Then things start to get interesting as the fertile U238 is changed into other things. I'm not saying that that actually happened, just that a hypothetical multi-kiloton pile of 65% natural uranium isn't a neutral pile of sand.

credit_guy 6y ago
Evaporation, oxygen and any number of other effects won't change the ratio of U235 and U238. Those isotopes are chemically identical. The only way they are different is by their different atomic mass, i.e. their gravitational effects. And since the atomic mass is different by only about 1%, even the gravitational effects are almost identical. So U235 constitutes between 0.71% and 0.72% of the Uranium everywhere in the world.
kenned3 6y ago
Exactly as the other guy posted. U235 doesnt do anything "interesting" until you get it to around 3%. Due to somewhat obvious reasons (not a lot of net-new uranium being formed, and the half life is fairly stable), the Uranium concentration is pretty uniform around the world and is something like: uranium-235 0.720% uranium-238 99.275% uranium-234 0.006% Evaporation and other factors wont change this, it hasnt changed this ratio in the muti-billion years Uranium has been on earth. What does change this is the half life of U235. U235 wont naturally 'accumulate', it doesnt move around in rock to form higher concentrations, it is generally 0.720 everywhere. The natural reactor ran becaues back then there was simply more U235 (half life 700 million years) vs the half life of U238 (4.5 billion years) No Hypothetical examples needed. Open pit mines wont do anything 'interesting' unless you can either go back in time, or reverse the U235 Decay and then add water and you will probably get something like what took place at Gabon.