Neutron activation analysis of impurities in thorium and zirconium matrices

A neutron activation method is described for the analysis of small concentrations of Cu, Cd, Mn, Co, Cr and Zn contaminants in thorium and zirconium compounds used for telecommunication and reactor techniques. The thorium matrix is separated from the contaminants by pre-irradiation paper chromatography and the²³³Pa is isolated after irradiation by extraction into methyl isobutyl ketone and precipitation with cupferron. For the analysis of the contaminant in zirconium compounds only precipitation with cupferron is used after irradiation. The individual impurities are determined by γ-spectrometry following separation.