Tracer-scale chemistry of volatile oxygen-bearing compounds formed by U, Pu and Cm

International Conference on Nuclear Chemistry

December 08-09, 2016 San Antonio, USA

Vladimir Panteleimonovich Domanov

Joint Institute for Nuclear Research, Russia

Posters & Accepted Abstracts: J Nucl Med Radiat Ther

Abstract :

Tracer-scale chemistry has some distinguishing characteristics which differ it from common (macro) chemistry. For example, the common redox reaction 2Pu(IV) + U(IV) â�� 2Pu(III) + U(VI) does not occur in extremely diluted solutions as collisions between microcomponents are practically excluded. Considerable differences in the chemical behavior micro- and macroquantities of some actinides in the gase phase had also been observed. The initial sample containd a tracer quantity of the actinide under study that was adsorbed on the surface of quartz powder. The experiments were carried out using open quartz thermochromatographic columns (I.D. = 3 mm); oxygen served as a reagent and helium was a carrier gas; the flow rate of the gas mixture was 20 cm3 minâ��1; the initial sample was heated in a gas stream at 700-750��C; the final part of the thermalgradient section was cooled to â��165��C; the temperature gradient was â��18��C cm-1; the duration of each experiment was 30 min. It was found that uranium formed volatile dioxide and troioxide that were adsorbed at 450�±25 and 250�±25��C. Two plutonium radioisotopes 238,239Pu were used in similar experiments. Contrary to the prevous results, plutonium formed three oxides. The centeres of their depozition zones were registered at 450�±30��C(PuO2), 250�±30��C(PuO3) and at â��105�±25��C(PuO4). In similar conditions, Cm formed also three oxides: CmO2, CmO3 and CmO4. They were adsorbed at 550�±25, 390�±25 and â��80�±50��C respectively. The values of adsorption enthalpy for these oxides on quartz and their chemical yields were determined.

Biography :

Email: domanov@jinr.ru