Radionuclides in Irradiated Graphite of Industrial Uranium–Graphite Reactors: Effect of Irradiation and Thermochemical Treatment on the Graphite Structure
| Autor: | M. S. Nikolsky, Alexey A. Averin, A. G. Volkova, Vasiliy O. Yapaskurt, Andrey A. Shiryaev, Elena V. Zakharova, Ekaterina A. Dolgopolova |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Thermal shock
Chemistry Analytical chemistry chemistry.chemical_element 02 engineering and technology Crystal structure Uranium 021001 nanoscience & nanotechnology 010403 inorganic & nuclear chemistry 01 natural sciences Fluence 0104 chemical sciences Amorphous solid symbols.namesake symbols Irradiation Graphite Physical and Theoretical Chemistry 0210 nano-technology Raman spectroscopy |
| Zdroj: | Radiochemistry. 60:664-671 |
| ISSN: | 1608-3288 1066-3622 |
| Popis: | The structure of irradiated graphite from decommissioned industrial uranium–graphite reactors was studied. The extent of disturbance of the graphite structure is closely correlated with temperature and integral neutral fluence. The perfection of the structure of graphite samples (data of X-ray diffraction and Raman spectroscopy) does not correlate with their radioactivity, which is due to low absolute concentration of the radionuclides. Mapping of the samples using Raman spectroscopy reveals spatial heterogeneity of the distribution of graphite lattice damages, which casts doubt on the representativeness of the spectra of individual points. The spatial distribution of domains differing in the crystal lattice perfection was studied for the first time and was compared with the radionuclide distribution. Satisfactory correlation between the radiographic and spectroscopic mapping data is observed for some samples. Irradiated graphite is strongly textured and contains amorphous microvolumes, which are probably radionuclide carriers. Thermochemical treatment (oxidation in O2, thermal shock) leads to degradation of the irradiated graphite structure on the submicron level, accompanied by a drastic decrease in the mechanical strength of the samples. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full text from SpringerLink