Development and applications of k0-based NAA using research reactors at BARC

Neutron activation analysis (NAA) using k0-based method has been standardized for the analysis of both small and large size samples in diverse matrices. The k0-based NAA using gold as single comparator was carried out by characterizing irradiation sites of research reactors at BARC and determining the k0-factors of some analytically important isotopes. The method was validated by analyzing reference materials (RMs) of different origin and applied to geological, environmental and biological samples. The k0-based Internal Monostandard NAA (IM-NAA) method was developed for the analysis of large size (g-kg scale) and non-standard geometry samples and applied to nuclear reactor structural materials namely zircaloys, stainless steels, nickel alloys and high pure aluminum as well as samples of wheat grains, uranium ore, dross and archaeological and modern clay ceramics. Large sample NAA work was performed for a pottery replica under inter comparison exercise of an IAEA CRP. For large size samples, thermal column at Apsara and graphite reflector position at AHWR Critical facility were characterized and used. (author)