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A semi-automated system has been developed for elution and concentration of the (188)Re-eluate from 111 GBq (3 Ci) (188)W/(188)Re-generators to provide a dissolved beta-source of high (188)Re-activity per unit volume. The elution progress and concentration were precisely and continuously monitored by use of collimated diode detectors. By using ion exchange cartridges, small eluate volumes (2-3 ml) of maximum 40 GBq, (188)Re/ml activity concentration were routinely prepared. The concentrated (188)Re solutions were used to beta-irradiate aqueous suspensions and solutions of iodine species to evaluate a simulation of the extent of radiolytic decomposition of chemical species (AgI and CH(3)I) expected to accumulate in the containment sump of a nuclear reactor in the event of a severe accident with reproducible dose rates of up to 0.4 Gys(-1). Results have shown that AgI colloidal particles decompose to varying extents, depending on conditions, and in proportion to their initial mass, which indicates surface oxidation. Experiments have also confirmed CH(3)I decomposition in proportion to initial aqueous concentration.

The decomposition of aqueous colloidal suspensions of AgI induced by ionizing radiation was investigated under various conditions using {sup 188}Re as an in situ beta-radiation source. The suspensions were stabilized by an initial excess of either I{sup -} or Ag{sup +} ions. Although the results were somewhat scattered, the following trends were observed. With an initial excess of I{sup -} and under strong oxidizing conditions (N{sub 2}O sparging) at pH 2, {approx}65% AgI was decomposed into nonvolatile and volatile iodine (ratio 2:1) for doses of {approx}20 kGy, and up to {approx}80% was decomposed (mostly nonvolatile iodine) at pH 5. Chloride ions greatly enhanced the volatile and lowered the nonvolatile fractions. Little decomposition (

Iodine is a biologically important trace element. Its behaviour in the environment and in human metabolism is determined by the type of iodine species which takes part in chemical reactions. Knowledge of their concentrations is necessary to understand and describe the iodine reaction paths. A separation procedure is proposed for quick determination of common forms of iodine—iodide, iodate ions, molecular iodine and organoiodine (in the form of CH3I). The procedure consists of sequential sorption by passing the sample solution first through a solid-phase extraction cartridge to separate I2 and CH3I from IO3 − and I− then through an anion-exchange resin in a cartridge to retain the latter two species. Each loaded cartridge is eluted to separate the sorbed pair of species. Concentration determination of the resulting four solutions can be performed by standard methods, e.g. by spectrophotometry, tracer counting or with ion-selective electrodes.

An analytical quick-test method was developed to determine iodide and iodate ions in aqueous solutions using solid phase extraction cartridges for sample preparation. Work was focussed on finding simple, but efficient conditions for quantitative separation of iodate and iodide. Iodine amounts were then determined by standard methods. Ion-exchange absorbers in cartridge form were used. Selectivity and yield of the species separation were studied at pH value of 5-10 and various solution compositions using 131I radioactive tracer. The electrolytes used were diluted alkaline, nitrate and boric acid-borate solutions. Application to nuclear reactor cooling water analysis or environmental investigations and monitoring is proposed.

A rapid method for the preparation of 87Y/87mSr radionuclide generator from a rubidium chloride target irradiated with 35 MeV α-particles is described. A simple two-step procedure is used to obtain a carrier-free 87mSr isotope with a high enough radiochemical yield and high purity in the final aqueous fraction.

Summary A new device was developed for the identification of several iodine species in aqueous solution using ion chromatography. Iodide, iodate and molecular iodine can be determined. (The equipment allows both conductivity and radioactivity detections.) The method is applicable for the determination of radioactive iodine contaminations in the cooling water of nuclear power plants.

The title goal was achieved using a DOWEX 50Wx8 cation exchange column saturated with La(OH)3 and ammonia solution as eluent. Hf, Ta and Lu were adsorbed on this column, whereas W remained in the solution. This chemical system may be used for fast on-line separations of element 106.

The sorption behavior of microamounts of Hf and Ta on DOWEX 50×8 and DOWEX 1×8 from aqueous HCl/HF solutions has been investigated. Suitable separation conditions for these two elements on cation exchange resins were found in solutions containing 1.5M HCl/10−4M HF and 0.05M HCl/10−3M HF. Kinetic experiments showed that the system can be applied in high speed on-line separations.

The short-lived isotopes of W and their descendants have been isolated from the products of the bombardment of144Sm with24Mg by a fast continuous ion-exchange method, using HF solution media. The feasibility of this method for isolation of element 106 is discussed.

Using nuclide Ru-106 the extraction of ruthenium by some usual organic reagents and various solvents has been studied with the aim to obtain informations on the complex chemical behaviour of ruthenium(IV) in diluted solutions and on the mechanism of the extraction. A characteristic of ruthenium(IV) species in solution is its reaction inertia which manifested itself in the influence of reaction time and temperature on the distribution ratio. It has been established, that with the most varied of reagents ruthenium(lV) forms stable complexes even in acid aqueous solutions, which may prevent a precipitation of the hydroxide or losses through the adsorption of the radiocolloides and permit an extractive separation of micro ruthenium quantities from aqueous solutions with yields of more than 90%.