The extractant, N,N,N 0 ,N 0 -tetraoctyl diglycolamide (TODGA) has been evaluated for the separation of actinides(III) and lanthanides(III) from a high active raffinate (HAR). The effect of oxalic acid and HEDTA complexant on the extraction of actinides(III), lanthanides(III), and important fission products (e.g. Mo, Pd, Sr, Zr, Ru etc.) from synthetic HAR has been studied with 0.2 mol/L TODGA in TPH.With an extractant mixture of TODGA and tributyl phosphate (TBP) the amount of oxalic acid can be reduced to less than 0.3 mol/L for the effective complexation of zirconium, whereas the distribution ratios of actinides(III) and lanthanides(III) are still high for the separation from HAR. Furthermore the maximum loading of lanthanides (e.g. Nd) can be significantly increased by adding TBP to the extractant. However, the extraction of oxalic acid and nitric acid also increased by the addition of TBP, which can lead to problems during back extraction of the loaded extractant. Extraction studies after radiolysis and hydrolysis reveal that the TODGA þ TBP mixture is a sufficient stable extraction system suited for further process development studies.

Within the framework of our research activities related to the partitioning of spent nuclear-fuel solutions, the direct selective extraction of trivalent actinides from a simulated PUREX raffinate was studied using a mixture of CyMe 4 BTBP and TODGA (1-cycle SANEX). The solvent showed a high selectivity for trivalent actinides with a high lanthanide separation factor. However, the coextraction of some fission product elements (Cu, Ni, Zr, Mo, Pd, Ag, and Cd) from a simulated PUREX raffinate was observed, with distribution ratios up to 30 (Cu). The extraction of Zr and Mo could be suppressed using oxalic acid but the use of the well-known Pd complexant N-(2-Hydroxyethyl)-ethylendiamin-N,N ,N -triacetic acid (HEDTA) was unsuccessful. During screening experiments with different amino acids and derivatives, the sulfur-bearing amino acid L-Cysteine showed good complexation of Pd and prevented its extraction into the organic phase without influencing the extraction of the trivalent actinides Am (III) and Cm (III). The optimization studies included the influence of the L-Cysteine and HNO 3 concentration and the kinetics of the extraction. The development of a process-like extraction series showed very promising results in view of further optimizing the process. A strategy for a single-cycle process is proposed within this article.

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The order-disorder phase transition in the Nd x Zr 1-x O 2-0.5x system is studied by complementary techniques which include wet chemical synthesis of a series of compositions with various Nd/Zr ratios with the final annealing at 1873 K, X-ray diffraction, oxide melt solution calorimetry and ab initio thermodynamic modeling.Our structural data indicate the transition from ordered to disordered pyrochlore at x ~ 0.31at a temperature of1873 K. Our calorimetric data show a transition enthalpy of ~30 kJ/mol, which corresponds to an entropy of disordering of ~16 J/K/mol. The latter value is significantly smaller than the configurational entropy of transition computed under the

Bimetallic Au-Ni supported on TiO 2 were prepared using co-depositionprecipitation with urea and tested on the selective hydrogenation of 1,3butadiene. The catalyst containing the lower amount of Ni (atomic Au:Ni 1:0.08) showed a satisfying compromise between activity provided by Ni and selectivity to butenes provided by Au for this selective hydrogenation reaction. Even though Au and Ni exhibit limited miscibility in the bulk, characterizations by TPR and UV-vis spectroscopy showed evidence of interaction between Au and Ni in nanoparticles. STEM-XEDS study confirmed the formation of bimetallic nanoparticles.