Glass Fabrication And Study Of Electron Rradiation Effect By Optical Absorption Spectrum

In order to optimize the energy structure, ensuring national energy security, Chinese nuclear power industry will be rapidly developed in the present and the future for a period of time. However, with nuclear power industry rapidly developing, a large number of high-level radioactive waste (HLW) will be produced. At present, proposed processing method of HLW at China is to vitrify HLW in glass, then the glass will be settled in the underground dispasal repository. In the meantime, the glass will be long-term in the environment of β decay of radionuclides and its network structure will be affected, leading to physical and chemical properties change. This can increase the risk of leakage of radionuclides into the biosphere. At present, the study at China of β irradiation effects on HLW glass is very limited at breadth and depth. It is not complete understanding at mechanism, which seriously influence Chinese nuclear industry to the healthy, stable and sustainable development.In order to study β irradiation effects on network structure at HLW glass, this paper used electron beam external irradiation to simulate electron irradiation environment during HLW glass storage. Three kinds of glass samples, called SiO2glass, NBS glass and HBS glass, were irradiated by1.2MeV electron. SiO2glass and HBS glass are commercial purchase glass, while NBS glass is refined in the laboratory, reference to foreign HLW glass component. In this paper, we used optical absorption spectrum (before and after electron irradiation) to study P irradiation effects at glass samples. By using this method, the changes of optical band gaps and network structures after electron irradiation at glass samples were obtained. The main results obtained in this paper were as follows:a) Electron irradiation leaded to the changes of optical band gaps at glasses. In SiO2glass, the optical band gap increased after electron irradiation. This may be due to the ground state level degradation after electron irradiation. However, in NBS glass and HBS glass, the optical band gap reduced after electron irradiation. The cause of this phenomenon may be the energy band and band-tail state extending to the low and high energy after electron irradiation. b) Due to single composition, the non-irradiated SiO2glass were almost no defects in studied optical range. The non-irradiated NBS glass and HBS glass had complex composition, containing E’-centers (≡Si-O·),Fe3+species and NBOHC (≡Si·)c) After electron irradiation, SiO2glass appeared two optical absorption bands, corresponding two kinds of defects, E’-centers (≡Si-O·) and NBOHC (≡Si·). At NBS glass, there were fore new optical absorption bands after electron irradiation and one of these corresponded to POL (≡Si-O-O-Si≡). However, At HBS glass, there were three new optical absorption bands after electron irradiation and one of these corresponded to POL (≡Si-O-O-Si≡)d) After electron irradiation, the structural defects in SiO2glass appeared not only few species, but also low concentration, showing the best electron radiation-proof ability. After electron irradiation, NBS glass emerged some new defects, however, the new defect had relatively low concentration, showing part electron radiation-proof ability. HBS glass after electron irradiation had new defects and the concentration of new defects was saturation at107Gy electron irradiation dose magnitude, showing the worst electron radiation-proof ability.