Year
1990
Abstract
We have developed a new technique, isotope dilution gamma-ray spectroscopy (IDGS), for simultaneously determining the plutonium concentration and the isotopic composition of highly irradiated fuel dissolver solutions, such as the input to a chemical reprocessing plant. IDGS, which combines high-resolution, low-energy gamma-ray spectroscopy, isotope dilution, and resin bead techniques, involves adding a well-characterized plutonium isotope (spike) to the unknown solution and then extracting the plutonium from the spiked (mixed) solution on resin beads and subsequently measuring the beads with high-resolution gamma-ray spectroscopy. The spike used in this experiment is a large-size dried spike of 239Pu. The plutonium concentration of the dissolver solution obtained from the first IDGS measurement agrees with that obtained by isotope dilution mass spectrometry (IDMS) within 0.2%. The rapid and accurate IDGS technique may provide a prompt and useful verification of input and intermediate process plutonium samples, which is very important for near-realtime accounting at reprocessing plants. It is also a potential on-site verification method for international safeguards. This paper describes the principle of the IDGS and the resin bead sample preparation and reports the preliminary results obtained by this new technique.