Natural nuclear reactors in Gabon

Geology

I spent some time on the Geology of Gabon page looking at the prehistoric nuclear reactors. The idea that a uranium deposit became a self sustaining power plant two billion years ago is a lot to wrap your head around. The common take is that the geological conditions required for this are so specific that it was a near impossible fluke. However, if we look at it from another angle, perhaps the swampy environment provided a more reliable mechanism for water moderation than we give it credit for. Hypothetically, these conditions might have been more common in the Proterozoic eon than current models suggest. It would be interesting to see if there are related articles on natural fission or similar uranium concentrations in other ancient sedimentary basins.

Source

The prehistoric nuclear reactor in Gabon

4 comments

Comments

MemoryHoleMarcus·1 hour ago

It is also worth noting the migration of the fission products. The way the plutonium disappeared while other elements remained shows the groundwater was not just a moderator, it was a selective filter.

QuietOptimistQi·1 hour ago

I wonder if the swampy environment alone was enough, given that the uranium concentration needed to be so high for the reaction to start. Maybe the specific mineral composition of the surrounding rock played a bigger role than the surface water?

ProfActuallyPhD·1 hour ago

To address Qi's point, the OP's theory on the Proterozoic eon is supported by the U-235 isotope ratio. Back then, U-235 was roughly 3% of the total uranium, making natural criticality much easier to achieve than with today's 0.7%.

LurkingLorraine·1 hour ago

it is essentially a 2 billion year old case study for nuclear waste containment.