Theoretical Study On Post - Treatment Of Nuclear Nuclear Fuel

Spent nuclear fuel reprocessing is the key to the sustainable development of nuclear energy. The effective separation of actinides and lanthanides from the high-level radioactive waste liquids is an important scientific problem of spent fuel reprocessing. Due to the strong radioactive toxicity of more actinides and lanthanides in nuclear wastes, leading to the difficulty in experimental exploration. Theoretical calculation has become an effective method for investigating actinide and lanthanide extraction separation behavior and ligand designs. In this thesis, a series of uranyl and lanthanide coordination compounds have been calculated using first-principles density functional theory(DFT). Associated with experimental results, the calculations which can give an insight into the nature of bonding interactions between metal cations and ligands are performed with CASTEP and DMol3 codes. A detailed investigation on the stability and electronic structures of the compounds is presented in this study. The results not only agree well with the experimental data but also lay the foundation to the design of novel ligands for actinide and lanthanide separation. In addition, this thesis has summarized the application of ionic liquids which have many advantages in the nuclear fuel cycle(NFC). Moreover, the study on the separation of actinide and lanthanide in a novel type of solvent ionic liquids using the first-principles molecular dynamics has been proposed as our future work.