Study On The Mechanical Properties Of Borosilicate Glass Induced By Xe Ions And Electrons Irradiation And The Preparation Of Zirconolite Glass Ceramic

The widespread use of nuclear energy produces a large amount of radioactive waste at the same time of benefiting mankind.Especially the long half-life,radioactive activity,high heat release rate,high toxic waste,high-level waste(HLW)waste is very difficult to deal with.Glass solidification technology has achieved industrial applications at present.However,glass is metastable in thermodynamics and irradiation can cause the properties change of glass.In the first part of this paper we use Xe ions irradiation to simulate ?-decay and electron irradiation to simulate ?-decay to study the variations of the borosilicate glasses mechanical properties.It was found that for Xe ions when the total deposited energy was around 6.6×1021 ke V/cm3,the hardness and modulus were reduced around 24% and 7.4%,respectively.And the mechanical properties of the glass solidified forms were improved after irradiation.When the glasses were irradiated by electrons,the hardness and modulus were decreased by about 4.7% and 2.9%,resepectively.Due to the limitation of the glass structure,it is semi-stable and the actinides capacity is low.It is not the best immobilisation materials for high level radioactive waste.The second part of this paper studies how to prepare a single phase zirconolite glass ceramic.The following results are obtained.The optimum molar ratio of the three elements(Ca : Ti : Zr)is 2 : 2 : 1.The best nucleation temperature and crystallization temperature are 1200 ? and 860 ? resepectively.When the crystallization temperature is lower than 860 ?,the main crystalline phase will be Ca2Ti2O6,while the crystallization temperature is higher than 860 ?,there will be a little Ti O2 and Zr O2 crystalline phases besides zirconolite.It was found that the cooling rate of molten glass has serious influence on microstructure of the glass ceramic: when the cooling rate is large enough,there are amount of zirconolite crystal blocks which uniformly distributed in the glass base,while the cooling rate is small,the size of crystal blocks become larger,and there will generate a little Ti O2 and Zr O2 crystalline phases in the samples.We doped with simulated nuclide Ce ions in order to study the infloance of zirconolite glass ceramic by actinide nuclides.With the increase amount of Ce O2,the lattice constant became larger,as well as the crystalline grain and crystallinity of samples.But the excessive amount of Ce O2 would lead precipitation of Si O2?Zr O2 and Ti crystalline phase.XPS analysis showed that Ce elements exist in trivalent and tetravalent two kinds of mixed valence in the glass ceramic.