79 Se与黄铁矿反应路径模拟研究

Simulation of Reaction Path Between 79 Se and Pyrite

79 Se是乏燃料中的一个裂变产物,在排放的乏燃料中所占的比例不到0.001%,但由于它的半衰期长达百万年(t 1/2=3.27×105年),又具有较强的迁移能力和生物可利用性,使79 Se成为高放废物地质处置中重点关注的少数几个放射性核素之一。本研究采用GWB模拟计算79 Se-黄铁矿体系的化学反应路径。实验室条件和野外条件下的模拟结果显示,SeO 32-与黄铁矿发生化学反应后,最终会以稳态的FeSe 2长期存在于地质环境中。黄铁矿作为高放废物处置库化学屏障材料理论上可行。此外,GWB模拟计算结果为更深入的开展放射性核素处置库化学屏障的相关研究和工程应用提供重要理论支持。

79 Se is one of fission products,which is less than 0.001%of total discharge spent nuclear fuel.But its half-life is above million years(t 1/2=3.27×105 ys).And it has high mobility and bioavailability.Thus,79 Se is one of the mainly concern radioactive nuclear for the geological disposal of high-level radioactive waste.GWB was used to simulate chemical reaction path of 79 Se and pyrite.The simulation in laboratory and field conditions showed SeO 32-,after chemical reactions with pyrite,will eventually persist in the geological environment as a steady-state FeS 2.Pyrite as a chemical barrier material for high level radioactive waste disposal repository is theoretically feasible.In addition,GWB simulation results provides important support for further research and engineering applications of chemical barriers in radio nuclear disposal reservoirs.