Some Evidence of Radiolysis in a Uranium ore Body - Quantification and Interpretation

Locally oxidising conditions in the near-field of the Cigar Lake uranium deposit was observed. Ongoing processes of water radiolysis has also been predicted previously by our mass transport model. In the ore there was an enhanced concentration of helium, hydrogen and sulphate. Sulphate is the only oxidising species of substantial amount in the groundwater samples, and is possibly indirectly produced by water radiolysis and oxidation of sulphides. The ongoing oxidant production rate has been calculated by the mass transport model.In this paper, the issue of water radiolysis is addressed from a more fundamental angle of approach. The maximum oxidant production rate is calculated based on the assumptions of geometric dispersion of the ore constituents, the estimate of the total radiation energy, the fraction of energy deposited into the pore water, and the G-values of water. The results show that only a few percent of the total radiation energy is deposited into the pore water to cause water radiolysis. If the recombination factor projected by other researchers are accounted for, the oxidant production rate thus calculated agrees with the present-day ongoing oxidant production rate predicted by the mass transport model.