8/10/2023 0 Comments Oklo natural reactorConcordance was found for all techniques and all materials at 1,740☒0 million (1.740☐.020×10 9) years B.P. Interstratified rhyolitic tuffs (also volcanic) were also analyzed. Associated pelites (clay-like rocks), microsyenites (igneous type of minerals) and volcanic rocks were dated using both Rb-Sr and K-Ar techniques. The Oklo uranium deposit is located in the middle Precambrian Francevillian formation. The natural fission reactor problem has been approached from three different perspectives: 1) Rb-Sr techniques for determining the age of the formation in which the Oklo deposits are located 2) determination of the radiogenic lead in the Oklo deposits 3) measurement of the ratio of fission products to the present concentration of U-235, and comparison of these ratios with the neutron flux that would have been associated with any decrease in U-235 by natural fission. Is there any physical evidence to suggest that such might have been the case? In other words, if the present laws and constants of nature had extended throughout the past, the Oklo uranium deposit could have become critical about 1.45 billion years ago, if all other necessary conditions were met at that time. Operating under the assumption that the decay constants for uranium have remained constant over geologic time, the U-235 concentration would be approximately 3% a about 1.45×10 9 years ago (less than three half-lives of U-235). The most probable set of conditions for a sustained nuclear reaction attainable under natural conditions at Oklo would involve neutron moderation by ordinary light water.īefore a sustained nuclear chain reaction with moderation by light water is possible, there must be an enrichment of U-235 to about 3% a. Therefore, the conditions of criticality there must have been different from those currently present. ![]() Neither of these conditions are possible under the normal conditions found in nature, nor has evidence for such conditions been found at the Oklo site. If uranium containing the natural 0.7202% a concentration of U-235 is used as the fuel, a sustained nuclear chain reaction is possible only under severe artificial geometric constraints of alternating uranium and moderator, or with unique neutron moderation by deuterium (Canadian natural-uranium "CANDU" power reactor). The possibility of a natural reactor occurring had been proposed as early as 1956 (Kuroda 1956). The only reasonable explanation for this depletion of U-235 was an ancient sustained nuclear chain reaction within the ore formation. Once the deviant ore was traced to its source, additional analyses produced one sample with a phenomenal low of 0.292% a U-235 (Naudet 1974). These analyses were systematically traced to the Oklo mine of the Franceville Uranium Mines Company in Gabon, Africa. Further analyses revealed U-235 concentrations as low as 0.621% a, with one core analysis exhibiting a low of 0.440% a. In June, 1972, a routine isotope analysis for U-235 content of uranium ore from Gabon, Africa, revealed a significant deviation from the standard 0.7202☐.0006% a U-235 (atom per cent). However, a candid question to ask would be: "Is there any hard physical evidence that would corroborate the large magnitudes of the decay rates apart from laboratory studies?" I believe that the answer is "Yes!" In addition to the radiohalo evidence found in various rock formations throughout the world (Brown 1990), the Oklo Natural Reactor Phenomenon, found in Gabon, Africa, contributes meaningful insight into the evaluation of radiometric decay rate constancy. Scientifically speaking, radiometric decay constants, once measured, remain unchanged except for minor adjustments due to the refinement of measurement techniques. The usual source of pressure causing an individual to question the constancy of the decay rates is one's own personal philosophy. Unless there are unusual (external and/or internal) pressures compelling an individual to question the constancy of radiometric decay rates, they are considered to be constant, with little reason for questioning. ![]() Download PDF JTHE IMPLICATIONS OF THE OKLO PHENOMENON ON THE CONSTANCY OF RADIOMETRIC DECAY RATES by
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