Authors:F. Macášek, V. Mikulaj, R. Kopunec, and P. Rajec
The specific phenomena accompanying the daughter nuclide formation by radioactive β-decay of complex parent compounds cause
certain deviations from a thermodynamic distribution of daughter elements in separation procedures (e.g. in radionuclidic
generators) and they are shown to complicate or, less probably, simplify their separation. A simple kinetic model has been
proposed to explain such processes as the distribution of some daughter nuclides of fission products by solvent extraction
with chelating compounds (systems of99Mo−99mTc and144Ce−144Pr with oxines).
Authors:F. Macášek, R. Kopunec, V. Mikulaj, P. Rajec, and A. Švec
Membrane extraction is treated as an analogue of solvent extraction in three-phase distribution systems. Its advantages and drawbacks are discussed with respect to separation and preconcentration of radionuclides, fission products of uranium and uranium itself.
Authors:F. Macášek, V. Mikulaj, P. Rajec, R. Čech, L. Mátel, R. Kopunec, J. Kuruc, and A. Švec
Radiolytical decomposition of phenol was investigated at60Co gamma irradiation (1–2 Gy·s–1, 10 kGy) of pre- and continuously aerated aqueous solutions at concentrations of phenol 1–100 mg· ·dm–3 and in the presence of sodium hydroxide, sulphuric acid, sodium and ferrous sulphate, formaldehyde, 2-propanol,n-hexane, xylene, benzene, and commercial gasoline. From the decomposition rate at doses 50–400 Gy, a phenomenological model of linear relation between the dose acquired for 37% decomposition (D37), initial concentration (g·m–3) of phenol (p0) and of an admixture (s0) was confirmed in the formD37=52ftr(p0+feqs0), wheref's are constants which can be attributed to the relative transformation resistance of phenol towards the OH radicals in given matrix (ftr, for pure waterftr=1) and relative acceptor capacity of competing substrate (feq). In real wastewaters, the efficient decrease of phenols content may be substantially lower than that in model solutions, obviously due to radiation oxidation of aromates, as proved by irradiation of aqueous solutions of benzene. Technical and economical feasibility of the process is discussed.
Authors:Ľ. Mátel, P. Rajec, V. Mikulaj, A. Švec, O. Rosskopfová, and L. Drahošová
Specific activity of239,240Pu in contaminated soils from the bank of Manivier channel was determined to be in the range of 5–40 Bq·kg–1 and for soils from the bank of Dudvah river 0.6–8 Bq·kg–1. The ratio of239,240Pu/137Cs found in the samples is about 1·10–4, which is very close to the ratio found in the pulp of high activity concentrate in the collecting tank of nuclear power plants (NPP).