Quartz KU-1 optical density measurements after irradiation in the nuclear reactor IR-8

摘要

Optical characteristics of quartz glass KU-1 were investigated after irradiation in a water-pull nuclear reactor IR-8 up to the fluence of 6×10~(190 n/cm~2. Quartz samples - cylinders with diameters 16 mm and heights 8 mm - were placed in two aluminum containers active zone in one of the central channel of the reactor IR-8 where the neutron flux was approximately equals 8×10~(13) n/cm~2 s. Quartz glass KU-1 optical characteristics were investigated after irradiation at the dose rate 4 kGy(Si)/s. Made from one melt, samples (though even this does not guarantee their complete identity) were irradiated up to the neutron fluence for the first group of 6×10~(19) n/cm~2 (gamma dose of 2.5 GGy) and for the second group of 6×10~(18) n/cm~2 (gamma dose of 270 MGy) at the temperature of 55 °C. Transparency spectra of unirradiated and irradiated samples, in the wavelength range from 0.2 to 2.5 m, were measured with the aid of a Hitachi Recording Spectrometer 20 days after irradiation. As it was observed at a lower fluence an essential degradation of the transparency took place in a wavelength region of λ<350 nm. In a region of 450-650 nm transparency decreased by 15%. At longer wavelengths no absorption was induced. The results of measurement have shown that the quartz of KU type may be used behind the shield in periscope channels or for windows behind the straight channel.