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Oklo, the Earth's Two-billion-year-old only Known Natural Nuclear Reactor (2018)

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Re: Oklo, the Earth's Two-billion-year-old only Known Natural Nuclear Reactor (2018)

#2

Post by wjnc »

This article could be so much better: How large are the estimated stores of ore that underwent natural fission? How much energy did it release and over how much time? When? Would this be noticable (and to whom)? So many questions, so little information.

I only know (or knew) high school physics, and when entering this in Claude I get an answer but am unable to verify the answer. Claude says 680 kWh gained per 0.03 grams of U-235 lost due to fission. I am left wondering into what the U-235 fizzed into (sorry, pun) and if I should take that into account.

Edit: There we go with modernity. I went to Claude instead of Wikipedia. Wikipedia at least has the answers. Thanks u/b800h. 100kW of heat on average. I can start filling in the blanks now.

Re: Oklo, the Earth's Two-billion-year-old only Known Natural Nuclear Reactor (2018)

#3

Post by b800h »

The Oklo region has now-exhausted Uranium deposits.

From Wikipedia:

"Some of the mined uranium was found to have a lower concentration of uranium-235 than expected, as if it had already been in a nuclear reactor. When geologists investigated they also found products typical of a reactor. They concluded that the deposit had been in a reactor: a natural nuclear fission reactor, around 1.8 to 1.7 billion years BP – in the Paleoproterozoic Era during Precambrian times, during the Statherian period – and continued for a few hundred thousand years, probably averaging less than 100 kW of thermal power during that time. At that time the natural uranium had a concentration of about 3% 235U and could have reached criticality with natural water as neutron moderator allowed by the special geometry of the deposit."

Re: Oklo, the Earth's Two-billion-year-old only Known Natural Nuclear Reactor (2018)

#6

Post by danielbln »

wjnc wrote: post #2

This article could be so much better: How large are the estimated stores of ore that underwent natural fission? How much energy did it release and over how much time? When? Would this be noticable (and to whom)? So many questions, so little information. I only know (or knew) high school physics, and when entering this in Claude I get an answer but am unable to verify the answer. Claude says 680 kWh gained per 0.03 gr…

Wikipedia is the best first point of entry, but if you do use Claude, just tell it to do web search for you: https://claude.ai/share/73e67582-3e03-454b-aa12-e8906bd7b3fd

Re: Oklo, the Earth's Two-billion-year-old only Known Natural Nuclear Reactor (2018)

#7

Post by the_arun »

wjnc wrote: post #2

This article could be so much better: How large are the estimated stores of ore that underwent natural fission? How much energy did it release and over how much time? When? Would this be noticable (and to whom)? So many questions, so little information. I only know (or knew) high school physics, and when entering this in Claude I get an answer but am unable to verify the answer. Claude says 680 kWh gained per 0.03 gr…

I wonder why Claude’s answers aren’t equal or better than Wikipedia - assuming Wikipedia is one of the training datasets. Is the temperature causing it to be probabilistic & other sources are carrying more weight?

Re: Oklo, the Earth's Two-billion-year-old only Known Natural Nuclear Reactor (2018)

#8

Post by Aardwolf »

> All natural uranium today contains 0.720% of U-235.

That's related to the material of our solar system all coming from the same supernova explosion or similar, right? Does this apply to our entire milky way or just the solar system? What if parts collided with material of _other_ origins and some of that is on Earth, then there could be different mixes, right?

Re: Oklo, the Earth's Two-billion-year-old only Known Natural Nuclear Reactor (2018)

#9

Post by pfdietz »

wjnc wrote: post #2

This article could be so much better: How large are the estimated stores of ore that underwent natural fission? How much energy did it release and over how much time? When? Would this be noticable (and to whom)? So many questions, so little information. I only know (or knew) high school physics, and when entering this in Claude I get an answer but am unable to verify the answer. Claude says 680 kWh gained per 0.03 gr…

Uranium was very enriched back at the formation of the Earth, so for a given geometry it would have been much more reactive.

However, uranium ores are often formed due to redox processes, since U(VI) is much more soluble than U(IV). So maybe concentrations wouldn't have been as common back before the Great Oxygenation Event about 2.4 Gya. Still, that leaves ~600 Mya between that point and this reactor, which would be not quite one half life of U235.

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