Ceramics-Silikáty 50, (2) 73 - 77 (2006)

The flow-through leaching experiments have been conducted at two buffered pH values (8.5 and 10.0) of borate leaching solutions and at two temperatures (70°C and 90°C) on the EUTAL glass fibers, used as an insulation in nuclear power plants. Time dependencies of the total amount of leached elements Si, Al and Ca in corrosive solution have been determined. From the leaching rates in stationary conditions the values of activation energies, Ea, have been calculated. Lower Ea values were found for leaching at higher pH value. Higher Ea values were found for atoms so called network-forming oxides (Si, Al). Surface of corroded fibers was analyzed by scanning electron microscopy with energy dispersive X-ray analysis (SEM/EDX). Formation of relatively smooth continuous surface layer of corrosion products was detected at higher pH value.