Local structure and cohesive properties of mixed thorium and uranium dioxides calculated by "ab initio" method

• Autorzy: Dąbrowski L. , Szuta M.
• Języki publikacji: EN

Abstrakty

EN

Density functional theory (DFT) results of calculations of the mixed thorium and uranium dioxide Th1-xUxO2 for the following mole ratio x = 0, 0.25, 0.75 and 1 are presented and discussed. "Ab initio" calculations were performed using the Wien2k program package. To compute the unit cell parameters the 12 atom super-cell were chosen. The lattice parameters were calculated through minimization of the total energy by the change of lattice parameters and atom displacement within the unit cell. Calculations were performed for five different exchange energy approximations EXC with and without corrective orbital potential U, and obtained lattice constants are presented graphically and compared with experimental data. It is established that the initially assumed oxygen location within the unit cell plus or minus 0.25 of the mixed compounds are not their equilibrium positions. The oxygen atoms within the unit cell undergo dislocation in the (111) direction. So, the distances oxygen-uranium are smaller than the distances oxygen-thorium. The change of local structure is presented graphically and appropriate parameters values are given in Table. The bulk modulus and the cohesive properties are also counted and shown graphically.

Słowa kluczowe

EN

uranium; thorium dioxide; DFT+U; LDA; GGA; local structure; cohesive properties; bulk modulus

• Wydawca: Institute of Nuclear Chemistry and Technology
• Czasopismo: Nukleonika
• Rocznik: 2012
• Tom: Vol. 57, No. 1
• Strony: 101--107
• Opis fizyczny: Bibliogr. 14 poz., rys.

Twórcy

autor

Dąbrowski L.

autor

Szuta M.

• National Centre for Nuclear Research (NCBJ), 7 Andrzeja Sołtana Str., 05-400 Otwock/Świerk, Poland, Tel.: [phone], Fax: [phone],

Bibliografia

• 1. Beauvy M (1992) Nonideality of the solid solution in (U, Pu)O2 nuclear fuels. J Nucl Mater 188:232–238
• 2. Blaha P, Schwartz K, Madsen G, Kvasnicka D, Luiz J (2001) Wien2k an augmented plane wave plus local orbital program for calculating crystal properties. Vienna University of Technology, Austria
• 3. Brooks MSS, Kelly PJ (1983) On the cohesive energy and charge density of uranium dioxide. Solid State Commun 45:689–692
• 4. Dorado B, Freyss M, Martin G (2009) GGA+U study of the incorporation of iodine in uranium dioxide. Eur Phys J B 69:203–209
• 5. Dudarev L, Nguyen Manh D, Suttopn AP (1997) Effect of Mott-Hubbard correlations on the electronic structure and structural stability of uranium dioxide. Philos Mag B 75:613–621
• 6. Geng HY, Chen Y, Kaneta Y, Kinoshita M (2007) Structure behavior of uranium dioxide under pressure by LSDA+U calculations. Phys Rev B 75:054111–8
• 7. Hohenberg H, Kohn W (1964) Inhomogeneous electron gas. Phys Rev B 136:864–871
• 8. Hubert S, Purans J, Heisbourg G, Moisy P, Dacheux N (2006) Local structure of actinide dioxide solid solutions Th1–xUxO2 and Th1–xPuxO2. Inorg Chem 45;10:3887–3894
• 9. IAEA (2005) Thorium fuel cycle – potential benefits and challenges. IAEA-TECDOC-1450. International Atomic Energy Agency, Vienna
• 10. Kohn W, Sham IJ (1965) Self-consistent equations including exchange and correlation effects. Phys Rev A 140:1133–1138
• 11. Petit T, Morel B, Lemaignan C (1996) Cohesive properties of UO2. Philos Mag B 73;6:893–904
• 12. Pujol MC, Iridi M, Havela L, Heathman S, Spino J (2004) Bulk and young’s modulus of doped UO2 by synchrotron diffraction under high pressure and knoop indentation. J Nucl Mater 324;2/3:189–197
• 13. Staun Olsen J, Gerward L, Kanchana VJ, Vaitheeswaruan G (2004) The bulk modulus of ThO2 – an experimental and theoretical study. J Alloys Compd 381:37–40
• 14. Yun Y, Kim H, Park K (2005) Electronic structure of UO2 from the density functional theory with on-site Coulomb repulsion. Nucl Eng Technol 37;3:293–298