Reactive transport modelling of uranium around a natural nuclear reactor at Bangombe (Oklo, Gabon)

摘要

On the Bangombe site (Oklo, Gabon), a natural nuclear reactor 1.95 Gy old, and 12 meters deep is submitted to weathering. The geochemical behaviour of uranium and trace elements around the reaction zone has been carried out using a reactive transport code HYTEC-2D. The buffer redox capacity of the organic matter associated with Fe~Ⅰ/Fe~ Ⅲminerals around the reactor can explain the uraninite stability into the reaction zone and its weak migration during the geological time.