ИСТИНА

Determination of technetium in the products of reprocessing of spent nuclear fuel is an important problem for the atomic industry. At the present time, radiometric and mass spectral methods and X-ray fluorescence analysis [4] are mainly used for this purpose. However, the above methods require rather complicated sample preparation, for example, for the radiometric determination of technetium, it is necessary to separate it from other radioactive isotopes, and other methods additionally require expensive equipment. Therefore, all these methods do not allow for the rapid determination of technetium at the sites of spent nuclear fuel. Potentiometric method using ISE is a good alternative to the above methods, because it does not require expensive equipment, it is quite easy to use and allows rapid analysis of spent nuclear fuel for technetium. However, this method has sufficient technetium detection limit (up to 10-7 mol / l) and high selectivity. Now, the potentiometric method for determining technetium is rarely used due to the lack of reliable TcO4 - selective electrodes. Still known two publications of using this electrodes. One of which describes liquid ISE specific to pertechnetate ions [5], are difficult to use because of structural features of the electrodes with liquid ion exchanger. Another described electrode with a polymer membrane can be used in a number of cases for fast SNF analysis for technetium content [7]. The proposed study is aimed at the development of an electrode membrane with improved electroanalytic characteristics for the determination of pertechnetate ions.Basic electroanalytical parameters have been determined for an ion-selective electrode (ISE) with a supramolecular polymer membrane containing polyvinyl chloride (PVC), a plasticizer onitrophenyloctyl ether, ionophor tetradecyammonium teraphertehtetate (PTTDF) and a lipophilic dopant tetraphenylborate tetradecylmonium. The electrode function of these ISEs was shown to be linear in the concentration range (TcO4)- 2⋅10-7÷ 10-2 mol / l; the slopes of the electrode function at 20 ° C are 57.5 ± 1.5 mV / p TcO4 - . The potentiometric coefficients of selectivity to various anions are determined. It was established that a change in the pH of the analyzed solution from 0.5 to 13 does not affect the potential. The possibility of using the ISE to determine Tc in the products of reprocessing spent nuclear fuel (SNF) is shown.