Abstract
Suitable separation techniques were prepared for actinide, 90St and 226Ra determinations in environmental and industrial samples. Extraction chromatography with tri-n-octyiphosphine oxide (TOPO) and di(2-ethylhexyl) phosphoric acid (HDEHP) solutions was, used. In some cases, a powder of Microthene (Microporous polyethylene) supporting solid TOPO was prepared thus obtaining a material showing better storing and column preparation features. Uranium and 226Ra were determined in phosphorites, phosphoric acid and phospbogypsam. Uranium, thorium and 226Ra were also measured in the low specific activity scales of hydrocarbon production equipment: 226Ra was found to concentrate in some parts of the plant so causing a radiation protection problem. Plutonium and 90St were measured either in some Mediterranean Sea samples or in environmental samples collected in Antarctica. Some interesting sea sediment profiles were also obtained. All the chemical methods were verified by: a) adding some yield tracers (232U, 228Th, 242pu); b) analyzing some certified samples supplied by IAEA and NIST; c) participating in some international intercomparison runs; d) using, when possible, both an analytical and a radiometric method and e) following the radioactivity decay or growth (90y and 226Ra). The determination of actinides in environmental and industrial samples is cf great importance for radiation protection purposes. Plutonium isotope measurements require a perfect separation and prolonged counts by alpha spectrometry; uranium and thorium measurements by gamma spectrometry can give rise to great errors when natural or artificial disequilibria are present or when the radionuclide concentration is low. This being stated, suitable separation techniques were prepared for the determination of the actinides by alpha spectrometry in several kinds of matrixes. 90Sr and 226Ra were also determined in some samples. Extraction chromatography 1 with tri-n-octylphosphine oxide (TOPO) and di(2-ethylhexyl) phosphoric acid (HDEHP) supported on microporous polyethylene (Microthene) was mainly used. The chemical procedures were verified by one or more of the following data quality control methods: a) by adding some yield tracers (232U, 228Th, 242pu); b) by analyzing some certified samples supplied by IAEA and NIST; c) by participating in some international intercomparison runs; d) by using, when possible, both an analytical and a radiometric method; e) by following the radioactivity decay or growth (90y and 226Ra).
Published Version
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