XPS Investigation of ceramic matrixes for disposal of long-living radioactive waste products

The synthesis of ceramic matrixes for the long-term storage of highly active radionuclide wastes and determination of physical and chemical forms of radionuclides in them is one of the important problems in radioecology. It enables to create purpose fully materials for the long-term storage of radionuclides. In the present work the samples of ceramics [CaCe0.9Ti2O6.8(I) and CaCeTi2O7(II}] formed under various conditions were investigated with the X-ray photo electron spectroscopy. It is necessary for synthesis of ceramic matrixes, for the disposal of the plutonium and others tetravalent actinides. A technique was developed for the determination of cerium oxidation state (Ce3+ and Ce4+) on the basis of the X-ray photo electron spectroscopy spectral structure characteristics. It was established that the sample (I) formed at 300 MPa and T = 1400 ?C in the air atmosphere contained on the surface two types of cerium ions in the ratio ? 63 atomic % of Ce3+ and 37 atomic % of Ce4+, and the sample (II) formed at 300 MPa and T= 1300 ?C in the oxygen atmosphere contained on its surface two types of cerium ions also, but in the ratio ? 36 atomic % of Ce3+ and 64 atomic % of Ce4+. It was established that on the surface of the studied ceramics carbonates of calcium and/or cerium could be formed under influence of the environment that leads to the destruction of ceramics. Sinteza keramickih matrica za trajno smestanje radioaktivnog otpada visoke aktivnosti i odredjivanje fizickih i hemijskih formi radionuklida u njima jedan je od znacajnih zadataka radioekologije jer omogucava da se stvore svrsishodni materijali za ove potrebe. U ovom radu, keramicki uzorci [CaCe0.9Ti2O6.8(I)i CaCeTi2O7(II)] oblikovani pod razlicitim uslovima proucavani su rendgenskom fotoelektronskom spektroskopijom u cilju sinteze keramickih matrica za potrebe odlaganja plutonijuma i drugih tetravalentnih aktinida. Razvijena je posebna tehnika za odredjivanje cerijumovog oksidacionog stanja (Ce3+ i Ce4+) na osnovu karakteristika spektralnih struktura dobijenih rendgenskom spektrometrijom. Utvrdjeno je da uzorak (I) formiran pri 300 MPa i T = 1400 ?C u vazduhu, sadrzi na povrsini dve vrste cerijumovih jona u atomskom odnosu 63% Ce3+ i 37% Ce4+, a da uzorak (II) nastao pri 300 MPa i T = 1300 ?C u sredini sa kiseonikom, sadrzi na svojoj povrsini takodje dve vrste cerijumovih jona, ali u drugom atomskom odnosu ? 36% Ce3+ i 64% Ce4+. Ustanovljeno je da na povrsini proucavanih keramika pod uticajem okoline