Work

The development of nuclear power causes some problems. The most actual one in this field is the problem of immobilization of radioactive nuclear materials and waste. So, a problem of selection of host material has arisen. Vitrification or immobilization of nuclear waste into a glass is the most universally employed method for its treatment. However, the useful life of such matrices is no more than 30–40 years. The effective alternative to vitrification has been immobilization of high-level wastes (HLW) in ceramic matrices and minerals. The central question is how effective a matrix will remain as a barrier over the required period of time, which for various isotopes varies from tens to tens of thousands years. Radiation stability of zircon ZrSiO4 has been studied using molecular dynamics method (MD). The mechanisms of damage of zircon structure due to α-decay of radio-active elements are studied in detail. Computer simulation of quartz SiO2, fluorapatite Ca10[PO4]6F2, zirconolite CaZrTi2O7, compound Gd2Zr2O7 with the pyrochlore structure and periclase MgO has been performed using MD method and quantum-chemical method. Results of this research can be used for solving both fundamental and applied ecological problems connected with immobilization and disposal of a high-level waste (HLW). In particular these results show, that during development of matrices for ecologically-safe immobilization of HLW it is necessary first of all to take into account the type of chemical bonding (or effective charge of oxygen atoms), topology of structure of matrix and “structure complication” (the number of different polyhedra, connected in oxygen positions, and the number of nonequivalent positions of oxygen atoms and cations in the structure). Matrices with the ionic type of bonding and with coordination structure are most perspective for long-term utilization of HLW.