Record of cycling operation of the natural nuclear reactor in the Oklo/Okelobondo area in Gabon.

Oklo Constraint on the Time-Variability of the Fine-Structure Constant

The Oklo phenomenon, natural fission reactors which had taken place in Gabon about 2 billion years ago, provides one of the most stringent constraints on the possible time-variability of the fine-structure constant α. We first review briefly what it is and how reliable it is in constraining α. We then compare the result with a more recent result on the nonzero change of α obtained from the obse...

The Natural Nuclear Reactor at Oklo: a Comparison with Modern Nuclear Reactors

Uranium contains only one naturally occurring isotope, 235U, which will sustain a nuclear chain reaction using normal water to moderate and reflect neutrons. At present, this isotope is present in low abundance (0.72%), requiring enrichment to 3% or greater for effective use in commercial nuclear reactors. Two billion years ago, however, the natural abundance of 235U was approximately 3%. Evide...

s . ge n - ph ] 6 A ug 2 00 3 Direct Test of the Time - Independence of Fundamental Nuclear Constants Using the Oklo Natural Reactor ∗

. ge n - ph ] 3 J ul 2 00 3 Direct Test of the Time - Independence of Fundamental Nuclear Constants Using the Oklo Natural Reactor ∗

Study of natural radioactivity to Assess of radiation  hazards from soil samples collected  from Mounana in south-east of Gabon

Background: The present work aims to determine the activity concentrations of 226Ra, 233Th and 40K in soil samples collected in Mounana in the Southeastern region of Gabon, to evaluate the contribution of the natural. Materials and Methods: An HPGe p-type detector coupled with a multichannel analyzer DSA-1000 was used to perform measurements and process data. Data acquisition and analysis were ...