Induced radioactivity of a concrete used for nuclear facility shields

An attempt is made to determine experimentally the presence and concentration of 45Sc, 59Co, 133Cs, 151Eu, 153Eu, 181Ta nuclides in the most widespread concrete aggregates (limestone, granites, and serpentinites) and also to calculate the aggregate activity appearing in the process of NPP operation. Aggregate samples from different deposits used to produce NPP biological shields, are investigated. Nuclide concentrations are determined by the activation method after irradiation in the IBR-2 reactor channel. Thermal, resonance and fast neutron flux densities constitute 1.1x1012; 0.23x1012 and 1.4x1012 cm-2xs-1, respectively. Analysis of the data obtained shows that long-lived activity of aggregates at cooling time > 0.5 year is determined by europium, cobalt and cesium. Induced specific activity of serpentinites is the maximum one of all the aggregates investigated