Ab initio study of solution energy and diffusion of caesium in uranium dioxide

Fission products stability in uranium dioxide

“…As in our previous contributions for Cs, Mo, Ba and Zr [14][15][16], calculations were performed using DFT method within GGA+U approximations. The stability of FP in urania has also been studied including calculations of solution energies of many compounds that are likely to be found in nuclear oxide fuels.…”

“…Finally, Ce displays a very low energy and belongs to the third group. From our previous calculations [14][15][16], we can include Cs in the first group, Ba and Mo in the second group, and Zr in the third one.…”

“…In order to better describe the localization of the f electrons of uranium in this compound, the GGA+U functional can be considered [12,13]. Very recently, we showed that the use of GGA+U functional leads to a better agreement with experimental data for solution energies of fission products, namely Ba, Zr, Cs and Mo in urania [14][15][16]. In this contribution, we extend our calculations of solution energies with GGA+U functional to He and other important FP for safety like Kr, Xe, I, Te, Ru, Sr and Ce.…”

“…Cerium oxide has a peculiar behavior since it is almost completely miscible with UO 2 . Since we are not able to take into account all the chemical complexity of both metallic and gray phases, we will consider prototypic phases which are expected to give a represen- tative model of complex phases together with the phases studied in our previous contributions [14][15][16] that can be observed in oxide fuels.…”

The solubility of cerium in La2Ti2O7 by DFT + U calculations

“…µ(La)is the and µ(O 2 ) are the total energies of bulk La 2 O 3 and free O 2 molecule, which are calculated to be -42.26 eV and -9.13 eV,respectively[31]. The vacancy formation energies are list inTable 2.The incorporation energy E Inc is defined as the energy required to incorporate a cerium in a pre-existing vacant lanthanum lattice site: E Inc (La 2-y Ce y Ti 2 O 7 ) = E(La 2-y Ce y Ti 2 O 7 ) -E(La 2-y Ce y' Ti 2 O 7 )-µ(Ce)[18,31,49].…”