Research Of DMG Chromatographic Method For The Radiochemical Separation Of ～(107)Pd

¹⁰⁷Pd is a long lived fission product, which is a pureβemitter with a maximal energy of 33 keV and a fission yield of 0.14%. It has been attract more and more attention because of its long life and the relatively higher fission yield, however, negative effect to the environments. So it is very meaningful to get the more precise nuclear data of this fission product. More over, to separate the noble metal have its industry value from high level liquid waste. The work we engaged in is to develop a no carder added procedure that can separate the fission product nuclide ¹⁰⁷Pd, which is pure enough to meet the requirement of the measurements of nuclear data especially the measurement of its half-life.Of all the separation methods of palladium, column chromatographic method has its advantage over the others on decontamination, operation, and have less waste liquid considering the subject has high radioactive level. These characters make the priority of column chromatographic method. Resins adsorbed some chelated regent have high selectivity to the objects, of all the chelated regent of palladium ion, dimethylglyoxmine (DMG) has long been used and tested to be an excellent regent in separating and determining palladium, so we resolve to use column chromatographic method with DMG in the resin as the column stuffing.The raw solution was converted to the medium of 1mol/L HNO₃, then loaded on a column filled with AmberliteXAD-7 resin which had been impragnated by 1% DMG-mathanol solution. After eluting with 1mol/L HNO₃, using methanol as desorption reagent, the palladium-DMG complex was dissolved in the methanol solution. The desorption solution was evaporated and dissolved by chloroform. The organic phase containing Pd was washed twice with 1mol/L HNO₃ to remove the impurity, then evaporated and dissolved by aqua regia. After converted to 1mol/L HNO₃ medium, the second column separation same as the first one was conduct. We use ¹⁰⁹Pd and many other radionuclides as tracers to determine the recovery and the decontamination factors of the procedure, and the procedure has been checked by the dissolved test fuel element of Qinshan Nuclear Power Plant. The average recovery of the whole procedure is about 30%, and the main loss happened in the steps of chloroform extraction and medium change. The procedure have very high decontamination factors of more than 2×10¹⁰ toαandβnuclides and more than 2×10⁸ toγ-emitting nuclide ¹³⁷Cs. Using this method we can separate the ¹⁰⁷Pd pure enough to meet the liquid scintillation counting. However, the content of palladium element in the solution of our fuel element is so low that we can not acquire any radioactive counts of ¹⁰⁷Pd by liquid scintillation counting. This may probably be due to the formation of the alloy which can not be dissolved by HNO₃, and a reasonable explanation of this phenomenon needs further study.