Background and Recent Advance for Isotopic Studies on the Oklo Natural Fission Reactors

Abstract

The Oklo uranium ore in the Francevillian basin at the Republic of Gabon is known as a fossil of natural fission reactor, because large-scaled fission chain reactions spontaneously occurred in the ore two billion years ago. It is of major concern to characterize the properties of nuclear reactors and to investigate the behavior of fission products in and around the reactors. In this review, geological and physic-chemical characteristics of the Oklo natural fission reactor and its implication for radioactive waste disposal are shown.