Fast, discontinuous separation procedures are described for zirconium, niobium, technetium and antimony from fission products.
Other rapid separation methods from aqueous solutions are summarized. The combination of a gas jet recoil transport system
with a continuous solvent extraction technique and with a thermochromatographic separation method is presented. The application
of such procedures to the investigation of new and already known short-lived nuclides is illustrated by some examples.
The possibilities for the separation of a complex fission product mixture by extraction chromatography have been investigated.
Here the partition coefficients between three solvents and hydrochloric acid are reported for the following elements: Zn(II),
Ge(IV), As(III), As(V), Se(IV), Zr(IV), Nb(V), Mo(VI), Tc(IV) Ru(III), Ru(IV), Rh(III), Ag(I), Cd(II), In(III), Sn(IV), Sb(III),
Sb(V), Te(IV), I(oxidized), Cs(I), Ce(III), Tb(III), Tm(III), Ac(III), Th(IV), Pa(V), U(VI), Np(IV), Np(VI). As solvents tri-n-butylphosphate
(TBP), tri-n-octylamine (TOA) and di-(2-ethylhexyl)-orthophosphoric acid (HDEHP) have been used. The partition coefficients
have been measured by batch-experiments in which the solvents were adsorbed on polytrifluoromonochloroethylene powder.
The performance of columns to be used for separations of fission products by extraction chromatography was studied as a function
of the loading of the support with extractant, of the flow rate and the temperature of the elutriant. Separations of molybdenum-technetium,
antimony-tellurium, zirconium-niobium and thorium-protactinium were used as examples to prove the effectiveness of this method.
The separation of fission products which form anionic species in mineral acids and of uranium and neptunium from samples of
neutron-irradiated uranium is described. The method used is extraction chromatography with tri-n-butylphosphate (TBP) and
di-(2-ethylhexyl)-orthophosphoric acid (HDEHP) as extractants and polytrifluoromonochloroethylene powder as the solid support.
In the first column Zr, U and Np are extracted with TBP from 8N HNO3/NaClO3. In the second column, HDEHP is applied as extractant and 9N HCl/NaClO3 as the mobile phase for the isolation of Nb, Sb, and I, and in the third column (HDEHP), the rare earths and Mo are extracted
from 0.1N HCl. Finally with the fourth column (TBP), Te and Tc are isolated from 6N HCl. These four groups of elements are further separated by elution from the columns. From the final effluent containing
Ru, Rh, Cs, Sr, and Ba, Ru is distilled from HClO4, and Rh is precipitated with NH4OH. The determination of chemical yields with X-ray fluorescence techniques is described for Zr, Mo, Te, Cs, Ce and U.
Authors:G. Skarnemark, J. Alstad, N. Kaffrell, and N. Trautmann
The multistage solvent extraction system SISAK is described. The system is used for online studies of nuclides with half-lives down to 1 s. Some of the chemical separation procedures are presented, and a survey is given on the results obtained so far. The possiblity to gain access to nuclides with even shorter half-lives is also discussed.
Authors:G. Naidu, N. Trautmann, S. Zaunar, T. Balaji, and K. Rao
The results of an instrumental neutron activation analysis of some elemental concentrations in different soil samples near the industrial areas at Tirupati, India, are reported. Altogether 14 elements, Sm, La, Cr, Co, Zn, Cs, Ce, Th, Rb, Na, K, Sr, Fe and Eu were determined. The samples were irradiated with neutrons at the 100 kW Triga - Mainz research reactor and the induced activities were measured by gamma-ray spectrometry using an efficiency calibrated high resolution high purity germanium (HPGe) detector in connection with a multichannel analyzer. The results are discussed.
Authors:J. Alstad, G. Skarnemark, F. Haberberger, G. Herrmann, A. Nähler, M. Pense-Maskow, and N. Trautmann
The H-0.3 liquid-liquid centrifuge applied for rapid and efficient separation of two liquid phases, and the HG-0.1 gas-liquid centrifuge used to separate the gas phase stemming from a gas jet transportation system and the liquid phase, have been further improved. New centrifuges have been produced of PEEK, a plastic material, which makes them resistant to most aqueous and organic solutions. The performance with respect to time behavior and phase purity is comparable to the titanium centrifuges used so far. The H-0.3 centrifuge has been applied to solvent extraction studies of Zr, Nb, Mo, Hf, Ta, W and Pa from HF solutions into tri-n-octylamine.
Authors:B. Wierczinski, J. Alstad, K. Eberhardt, J. Kratz, R. Malmbeck, M. Mendel, A. Nähler, J. Omtvedt, G. Skarnemark, N. Trautmann, and N. Wiehl
Fast solvent extraction is a chemical separation method, which can be applied to study exotic nuclides. Since about 1970 the
SISAK technique, which is an on-line method based on multi-stage solvent extraction separations, has been successfully used
to investigate the nuclear properties of β-decaying nuclides with half-lives down to about one second. During the last decade
it has become possible to produce transactinide elements in high enough yields to investigate their chemical properties on
a one-atom-at-a-time scale. For this purpose it was necessary to improve and change the detection part of the SISAK system
in order to be capable to detect spontaneously fissioning and α-decaying nuclides in a flowing organic solution. This technique
is based on liquid scintillation counting with pulse-shape discrimination and pile-up rejection
Authors:B. Wierczinski, K. Gregorich, B. Kadkhodayan, D. Lee, L. Beauvais, M. Hendricks, C. Kacher, M. Lane, D. Keeney-Shaughnessy, N. Stoyer, D. Strellis, E. Sylwester, P. Wilk, D. Hoffman, R. Malmbeck, G. Skarnemark, J. Alstad, J. Omtvedt, K. Eberhardt, M. Mendel, A. Nähler, and N. Trautmann
Subsecond 224 Pa (T1/2 = 0.85 s) was produced via the 209 Bi(18 O,3n)224 Pa reaction at the 88 inch cyclotron at the Lawrence Berkeley National Laboratory. After production it was transported via a gas-jet system to the centrifuge system SISAK 3. Following on-line extraction with trioctylamine/scintillation solutions from 1M lactic acid, 224 Pa was detected applying on-line -liquid scintillation counting. Unambiguous identification was achieved using time-correlated --decay chain analysis. This constitutes the first chemical on-line separation and detection of a subsecond -decaying nuclide, 0.85-s 224 Pa with the fast extraction system SISAK 3.