Nuclear Fission Chain Reactions of Nuclides in the Earth’s Core over Billions of Years

Abstract

Numerical simulation is used to study the possibility of long-term chain nuclear reactions deep inside the Earth over 4 billion years. The active layer (the natural nuclear reactor operating on fast neutrons in lakes) can form when uranium oxides or carbides precipitate from a liquid layer onto the Earth’s solid interior core. A mechanism of uranium concentration in the Earth’s core is studied, experiments are performed, and it is shown that a nuclear chain reaction with breeding of fissioning nuclides could have occurred in such a layer. The basic neutron-physical characteristics of such a natural nuclear reactor are calculated. It most likely operates in a pulsed mode. The critical condition for the duration of the reaction is the power level. It is found that for certain optimal power this process in the Earth’s core can last for more than 4 billion years up to the present time.