The Workings of an Ancient Nuclear Reactor (2009) | Hacker News Reader

The Workings of an Ancient Nuclear Reactor (2009)

scientificamerican.com

90 pointsHooke12 comments

In geology, there is a general tendency to think that, given sufficient time (which we have had), anything that could possibly happen has already happened at least once. This is a prime example of that.

Are there any more similar stories like this? It's really fascinating.

I don't know about other nuclear physics type phenomena, but some reasonably unthinkable things that probably happened include the earth being completely encased in ice[1], all of the continents colliding into a supercontinent[2], a volcano big enough that it was essentially a crack in the earth with basalt lava (>1000°C) pouring out at 4x the flow of the Amazon for a week (in which it flowed hundreds of miles)[3], or (one of my favorites, though it's just kind of neat and not so mind-blowing) ammonite seashells that have had the original calcite shell naturally replaced with pyrite (fool's gold) so there are completely natural metallic fossils[4].

[1]: www.snowballearth.org [2]: https://en.wikipedia.org/wiki/Pangaea [3]: http://en.wikipedia.org/wiki/Columbia_River_Basalt_Group [4]: https://www.google.it/search?q=ammonites+replaced+with+pyrit...

Maybe.

There is apparently some evidence and viable theories for ongoing fission reactions in localized regions deep in the Earth. Commentary [1] on a report in Nature [2]. Neither of these seems to be paywalled.

[1] http://www.nature.com/news/2008/080515/full/news.2008.822.ht...

[2] http://www.nature.com/articles/srep37740

Thank you for these links. I had recently read on wikipedia [1] about how plate tectonics may have started on the young earth, and I was fascinated by the idea. In a way, tectonic theory is relatively new, and already we are exploring the mantle mechanisms by which it may be driven. Your links help explain where that mantle heat comes from.

[1] https://en.wikipedia.org/wiki/Boring_Billion#Tectonic_constr...

TL'DR - some Uranium deposits have unnaturally low concentrations of Uranium U-235. There is proof in the footprint of the occurrence of fission products that this must be due to natural fission having taken place way in the past.

That was what was reported in the 1970's. This article covers new analysis that provides evidence that water was the mediator, and also carried away the reaction products. When they went looking for those reaction products, they found them in nearby compounds that might prove valuable to us in sequestering our radioactive waste.

This is my take away quote: In this regard, it was extremely effective, allowing not a single meltdown or explosion during hundreds of thousands of years.

And runner up: The more important lessons may be about how to handle nuclear waste.

re: 'allowing not a single meltdown or explosion'

..and I'm wondering now, will we one day find evidence of an actual 'natural' nuclear explosion somewhere else?

Hiroshima-style explosions. I doubt that. Nuclear bombs use highly enriched uranium or plutonium and use inertial confinement, which requires an precisely controlled explosion.

A Tchernobyl-style explosion, caused by water being heated by a runaway nuclear reaction is more likely to happen naturally.

Every single day for the past 6.4 billions years in our sun.

Our sun can't come close to the temperature reached in advanced fusion weapons, and it exhibits the power density of a compost pile.

8/10

Reply on news.ycombinator.com