Studies on Separation of 90Y and 90Sr Separation from Hydrochloric Acid Solutions Using TODGA as the Extractant by SLM Method

AbstractYttrium-90 is an important radionuclide known for its therapeutic application in nuclear medicine. Solvent extraction studies with N,N,N’,N’-tetra-octyldiglycolamide (TODGA) has shown that Y(III) is well extracted in 6M HCl while at the same time, extraction of Sr(II) is very low leading to a separation factor (DY/DSr = 60,000). This property of TODGA can be exploited for the separation of Y from Sr. The aim of this present work is to produce carrier free 90Y by using Supported Liquid Membrane (SLM) based separation of Y and Sr with TODGA as the carrier. Solvent extraction studies with various diluents viz. 1-decanol, xylene, MIBK, chloroform etc. indicated that xylene and n-dodecane are most suitable as S.F. >50,000 are obtained. Based on the results, a SLM based separation scheme was developed using 0.1M TODGA in xylene loaded on a microporous PTFE membrane as a polymeric support and 6M HCl as feed and 0.01M HCl as strip phase. The results appear promising for the development of SLM based Y-90 generator. The purity of the product was ascertained by the half life method

Anomalous behaviour of the low-temperature heat capacity for KCl crystals with heavy univalent impurities

De faibles concentrations d'impuretés lourdes et monovalentes Cs+ et I- ont pour conséquence une augmentation de la chaleur spécifique de KCl à basse température. Ce comportement anormal a été expliqué à l'aide d'une théorie utilisant une fonction de Green, pour de faibles concentrations. Les calculs ont été effectués grâce à un modèle de perturbation localisée qui inclut un changement de masse sur le site de l'impureté aussi bien qu'un changement des constantes de forces radiales avec les plus proches voisins. Un accord raisonnable est obtenu avec les données expérimentales. La contribution du défaut de masse est de 80 % du changement de la chaleur spécifique ; la contribution restante est due aux changements de constante de force. Les contributions les plus importantes au changement de chaleur spécifique sont due aux modes impairs de symétrie F1u. La partie réelle du dénominateur de résonance dans la représentation irréductible F1u donne une fréquence quasi localisée. La valeur trouvée de la fréquence de résonance dans le cas de KCl : I- est voisine de celle obtenue précédemment par l'étude de la conductivité thermique du même système.The effect of low concentrations of heavy univalent Cs+ and I- impurities on the low-temperature heat capacity of KCl gives an enhancement in the heat capacity. This anomalous behaviour has been explained on the basis of a low concentration Green's function theory. A localized perturbation model which includes mass change at the impurity site as well as changes in the nearest neighbour radial force constants has been employed in performing the calculations. Reasonable agreement with the experimental data is obtained. The mass defect contribution is found to be 80 % of the changed specific heat and the remaining contribution is due to force constant changes. The main contributions to the changed specific heat is caused by odd parity F1u-symmetry modes. The real part of the resonance denominator in F1u-irreducible representation gives a quasi localized frequency. The present value of the resonant frequency in case of KCl : I- is seen to be similar to those obtained earlier in the study of thermal conductivity of the same system

Measurement of the neutron capture cross-section of

The 232Th(n,$\gamma$) reaction cross-section at average neutron energies of 3.7±0.3 MeV and 9.85±0.38 MeV from the 7Li(p, n) reaction has been determined for the first time using activation and off-line $\gamma$ -ray spectrometric technique. The 232Th(n, 2n) reaction cross-section at the average neutron energy of 9.85±0.38 MeV has been also determined using the same technique. The experimentally determined 232Th(n,$\gamma$) and 232Th(n, 2n) reaction cross-sections were compared with the evaluated data of ENDF/B-VII, JENDL-4.0 and JEFF-3.1 and were found to be in good agreement. The present data along with literature data in a wide range of neutron energies were interpreted in terms of competition between different reaction channels including fission. The 232Th(n,$\gamma$) and 232Th(n, 2n) reaction cross-sections were also calculated theoretically using the TALYS 1.2 computer code and were found to be slightly higher than the experimental data