Authors:H. Furusawa, J. Sarkis, M. Kakazu, and C. Rodrigues
A sector field mass spectrometer using an inductively coupled plasma as an ion source was used in order to determine the uranium
isotopic ratios in reference materials supplied by the National Institute of Standards and Technology (NIST) (NBS 950, 010,
030, 200, 500, 750, and 970). The accuracy obtained for the major isotopes was better than 0.2%.
Authors:J. H. Buchmann, J. E. S. Sarkis, M. H. Kakazu, and C. Rodrigues
The use of environmental monitoring as a technique to identify activities related to the nuclear fuel cycle has been proposed
by international safeguards organizations. The elements specific for each kind of nuclear activity, or “nuclear signatures”,
inserted in the ecosystem can be intercepted by different live organisms. This work demonstrates the technical viability of
using pine needles as bioindicators of nuclear signatures associated with uranium enrichment activities. Additionally, it
proposes the use of HR-ICP-MS to identify the signature corresponding to that kind of activities in the ecosystem. Nitric
acid solutions, used to wash pine needles sampled near nuclear facilities and containing only 0.1 mg . kg-1 of uranium, exhibit a n(235U)/n(238U) isotopic abundance ratio of 0.0092±0.0002, while solutions originated from samples collected at places located more than
200 km far from activities related to the nuclear fuel cycle exhibit a value of 0.0074±0.0002. Similar results were obtained
for sample solutions prepared using the acid leaching process. The different values of n(235U)/n(238U) isotopic abundance ratio obtained permit to confirm the presence of anthropogenic uranium and demonstrate the viability
of using the methodology proposed in this work.