Natural Nuclear Reactors

bungeejumper writes "The Astronomy Picture of the day has a picture of a natural nuclear reactor discovered in an uranium ore mine in Africa. This link has much more detailed information on this subject. Does this tie in with this wacky story about a HUGE PLUTONIUM FAST BREEDER REACTOR at the centre of the earth ?"

Comments

Magnetic field

[u19925]

You don't need nuclear reactor to explain magnetic field. Whereever in nature, there are ionized particles and systematic rotation, magnetic field is found. Stars, neutron stars, galaxies (spiral galaxies have more magnetic field because they have systematic rotation while elliptical galaxies have less magnetic, since the star motion in them is random). Earth interior is at very high temperature, so, ionized particles are expected. Couple that with systematic rotation, and you have a magnetic field. Heavy objects in general produce more ionized in the interior than lighter object. Thus moon which has very small rotation and smaller in mass has no detectable magnetic field. Why would a nuclear reactor exist in earth's core but not on moon? Why would magnetic field exist on jupiter, saturn?

The heat in lava can be explained by the heat transfer from the core. Earth's thermal conductivity is so small, that the heat trapped in the interior needs billions of years to come out and it is stil coming out. Additionally, earth contains some radio active material too, which generates additional heat. There are some theories in which relative importance of these two effects is different.

No connection

[f97tosc]

There is little connection between the two topics.

The 'reactors' are of different types, and the center of earth one is something that is only predicted by a controversial model.

The surface reactors in Africa are extremely interesting and have been known for quite some time now.

They are also a powerful argument for nuclear power plants.

After all, here is an example of how the radiocative by-products of fission have been stored safely for millions of years - without any sophisitcated protection technology.

Tor

Sci Fi

[WeaponOfChoice]

If I remember rightly the idea had a recent ressurgence in the Stephen Baxter book Time (Manifold series, interesting read). The 'reactor' (read: large pile of fissile material maintained by people suffering terminal radiation poisoning) was used to power a small teleport system. Nice mix of the primative and super high tech.

Radioactive Decay?

[Gerry Gleason]

I thought the conventional thought about the Earths core involved radioactive decay slowing the general cooling trend. I didn't see any reference to this. What about all the individual things the theory claims to have a better explaination for? I guess I'm asking how solid is the conventional model? Regardless of the merits of this theory, is it possible that there are concentrations deep in the Earth?

Re:The story is only 26 years old, a new record

[Observer]

I recall a short story in - I think - a SciFi anthology published a few years after the Scientific American article, which related that a similar concentration of uranium ore had been found very near the surface, but where conditions had not been sufficient to sustain even a slow chain reaction. Until, that is, the ore was uncovered, and then either through natural rainfall or because of water pumped through the site as part of its exploitation, enough of the fast neutrons were moderated down to slower energies that the the deposit as a whole crossed the criticality threshold, and... Fwoom.

--
When Dinosaurs Ruled the Earth - a book of recollections of the days of the mainframes, by one who was there.