Reactor at Earth's Core?

An anonymous submitter sent in this story suggesting that uranium in the Earth's core may be acting as a giant breeder reactor, generating a large amount of heat and perhaps being responsible for the Earth's magnetic field.

Comments

Primary Literature

[Wayne Hoxsie]

As usual, the pop science publications do this little justice. The primary literature is published by the Proceedings of the National Academy of Sciences and is published online at: http://www.pnas.org/cgi/content/full/98/20/11085 and certainly makes the case sound more convincing.

The article at EV world doesn't didn't, to my dismay, discuss the electro-magnetic implications at all. It sounded like a stretch to me to conflate geomagnetism with a nuclear process.

Only if you don't read it carefully

[texchanchan]

Re, ...the article authours propose no mechanism for their magical solid-state fission reactor to turn on and off...

Yes, they do:

"One might imagine instances in which the rate of production of [neutron-absorbing] fission products exceeds their rate of removal by gravitationally driven diffusion," Herndon wrote in a recent paper on the subject. If so, he explained, "the power output of the geo-reactor would decrease and the reactor might eventually shut down, thereby diminishing and ultimately shutting down the Earth's magnetic field."

Over time, as the lighter elements moved away from the uranium core, the reactor would restart.

Also, re Without a really strong mechanism operating to separate it out and concentrate it, it's going to remain a trace impurity in other ores, and not a ball at the center of the Earth.

There is such a mechanism. Everyone agrees that the core is iron. How did that happen, when the Earth coalesced from random rocky materials? The same way. If iron, why not uranium? From the article:

...over time, solid uranium particles would rain out from Earth's fluid core at high temperatures. Because of their high density, they could collect at the very center of the Earth.