北祁连山变质杂岩中榍石的结构演化及稳定性研究

Research on the Structural Evolvement and Stability of Sphenes from Metamorphic Rock in the North Qilian Mountain

作为固化放射性元素的备选矿物榍石赋存于结晶岩中,其稳定性对于核废物固化体的安全性评估意义重大。在利用XRD和EDS等手段对北祁连山变质杂岩体中的副矿物榍石的研究中发现,榍石含有3.46%的锶和铯、0.80%的铀以及其它杂质元素,虽经历了约775 M a的地质演化和所含放射性元素的衰变作用,但晶体形态保存完好,晶体结构几乎没有变化,晶胞参数仅发生了极小的变化,△a=-0.0009 nm、△b=0.0018 nm、△c=0.0002nm、△β=-0.10°,结晶度仍高达99.27%,表明其稳定性满足百万年尺度的安全性要求。

Sphenes, as crystalline solid of radioelements, exists in the crystallography, its stability has an important significance for security estimate of the solid including nucleur waste material. They are discov- ered by the XRD and EDS study of the sphenes from metamorphic rock of the Niuxin hiU in the North Qilian mountain area： There are 3.46% strontium and caesium, 0. 80% uranium and foreign matter in the sphenes ; Though the sphenes had undergone about 775 Ma geological evolvement and alpha decay ac- tion of its radioelements, but the crystal shape and structure of the sphenes are still very fine, the change of the sphenes crystal parameters is still very little,△a=-0.0009nm、△b=0.0018nm、△c=0.0002nm、△β=-0.10°,99.27% crystallinity is very high. The above study may tell us that the stability of the sphenes with radioelements can satisfy the goal of more Ma rule security.