Model Assessment of the Migration Capability of Transuranium Radionuclides (~(241)Am and Pu Isotopes) and ~(152)Eu in the System Bottom Sediments-Yenisei River Water by Chemical Fractionation Technique

摘要

Sorption of radiotracers ~(241)Am and ~(242)Pu and weighable amounts of uranium and stable Eu on bottom sediments in the simulated system bottom sediments-Yenisei river water was studied. At a contact time of 40 min these metals are completely sorbed on the bottom sediments, presumably via association with organomineral complexes and hydrated gels. Along with sorption, these metals can form soluble complexes and stable colloids (pseudocolloids). The distribution factors of ~(241)Am and ~(242)Pu, and stable Eu in the simulated system between bottom sediments and liquid phases were calculated from the results of sorption experiments. The introduced ~(241)Am and ~(152)Eu initially present in radioactively contaminated bottom sediments of the Yenisei river show similar pattern of distribution over differently mobile fractions. The distribution of weighable amounts of stable Eu significantly differs from that of initially present ~(152)Eu and tracer ~(241)Am due to decelerated sorption of stable Eu and its considerably higher concentration. A significant part of ~(242)Pu, ~(241)Am, and ~(152)Eu is associated with mobile fractions of bottom sediments, which, under certain environmental conditions, can pass into river water as migrating species.