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MD study of radiation damage in zircon in connection with the problem of utilization of high-level wasteтезисы доклада
- Авторы: Grechanovsky A.E., Urusov V.S.
- Сборник: 29th European Crystallographic Meeting Book of Abstracts
- Тезисы
- Год издания: 2015
- Место издания: Rovinj
- Первая страница: 303
- Последняя страница: 304
- Аннотация: Vitrification, or immobilization of nuclear wastes into glass, is the most widespread method of their treatment. However, the service life of such matrices is no longer than 30-40 years. An alternative to vitrification of nuclear wastes is utilization of high-level waste (HLW) in ceramic matrices and materials. Many authors have considered zircon as a matrix for the disposal of nuclear fuel and weapons-grade plutonium. However, over the geological time, the alpha-decay of uranium and thorium atoms has brought about a damage of the structure of zircon and its transition from the crystalline state to the X-ray amorphous (metamict) state. The purpose of the present work was to investigate the mechanisms of formation of a cascade of atomic displacements in the structure of zircon due to the alpha-decay under the action of recoil nuclei. The radiation damage in zircon was investigated by the method of molecular dynamics (MD). This method consists in calculating trajectories of the motion of all atoms involved in a system on the basis of Newtons second law. As a recoil nucleus for a zircon nanofragment in size containing about 5 million atoms, we used the knock-on atom of thorium (analogue of the recoil atom) with the energy of 20 keV. As the program for the MD modeling, we used the program complex DL_POLY. The computer calculations were fulfilled on the supercomputer SKIF MSU CHEBYSHEV.In whole obtained results show that in zircon every alpha-decay of radioactive elements results in the origin of amorphous area. These results also indicate that most correct model of zircon amorphization is the direct impact model of amorphization.
- Добавил в систему: Еремин Николай Николаевич