georeactor

plural georeactors

1. A geologically occurring slow fission reactor, especially in the Earth's past.

   Physicists analyzing a tiny sample of this ancient georeactor—discovered in the African country of Gabon in 1972—have now determined how it worked.

   2005 February 4, Jessa Forte Netting, “Nature's Nuclear Reactor”, in Discover Magazine

2. Any man-made industrial structure built into the Earth's crust and operating on the principle of nuclear fission.
3. The theorized natural fission reactor at the center of the Earth which would account for the geomagnetic field.