17O and 18O analysis of heavy water

Abstract

Nine samples of heavy water (>99% D 2O) from the Bruce Heavy Water Plant and one Lake Huron water sample were analysed for 17O/ 16O and 18O/ 16O isotope ratios using the CO 2H 2O equilibration technique. Two samples of moderator water, one from Douglas Point Nuclear Generating Station and one from Pickering Nuclear Generating Station, were analysed for 17O/ 16O and 18O/ 16O isotope ratios using carbon reduction in a nickel vessel. The results show an enrichment of >50% in 17O and >100% in 18O relative to the Lake Huron Water sample. The enrichment is shown to occur exclusively during the finishing (distillation) stages of heavy water production. The relationship between 17O and 18O enrichment yields a line of slope = 0.5 as expected for equilibrum mass dependent fractionation processes. The results from the two samples of nuclear reactor moderator water also lie on this line.