Authors:Weihua Zhang, Kurt Ungar, Ian Hoffman, and Ryan Lawrie
To support interpretation of observed atmospheric krypton radioisotopes, a database of krypton radioisotope in the primary
coolant of CANDU reactors has been established. This database is comprised of 40,000 records of high-quality 89Kr, 87Kr, 88Kr and 85mKr analyses. Records from the database were retrieved by a specifically designed data-mining module and subjected to further
analysis. Results from the analysis were subsequently used to study isotopic ratios of observed krypton radioisotopes in the
CANDU reactor primary coolant. These studies provided practical information on the characterization of CANDU reactor krypton
radioisotope, which can potentially be used to discriminate between reactor effluent and fuel reprocessing for nuclear safeguard
85Kr monitoring applications (Kalinowski et al., J Environ Radioact 73:203, 2004). The study also has some potential application
to Fissile material cut-off treaty.
Authors:Weihua Zhang, Jarmo Ala-Heikkila, Kurt Ungar, Ian Hoffman, and Ryan Lawrie
Based on the Linssi database and UniSampo/Shaman software, an automated analysis platform has been setup for the analysis
of large amounts of gamma-spectra from the primary coolant monitoring systems of a CANDU reactor. Thus, a database inventory
of gaseous and volatile fission products in the primary coolant of a CANDU reactor has been established. This database is
comprised of 15,000 spectra of radioisotope analysis records. Records from the database inventory were retrieved by a specifically
designed data-mining module and subjected to further analysis. Results from the analysis were subsequently used to identify
the reactor coolant half-life of 135Xe and 133Xe, as well as the correlations of 135Xe and 88Kr activities.
Authors:Weihua Zhang, Jing Yi, Pawel Mekarski, Ian Hoffman, Kurt Ungar, and Ari-Pekka Leppänen
In this study, a gamma–gamma coincidence spectrometry was developed and examined for environmental low-level cosmogenic 22Na monitoring purposes. The spectrometry consists of two bismuth germanate scintillators (BGO) and XIA LLC Digital Gamma Finder
(DGF)/Pixie-4 software and card package. The developed spectrometry was optimized according to the considerations of output
count rate and gamma peak energy resolution. This spectrometry provides a more sensitive and effective way to quantify even
trace amounts of 22Na with critical detection limit of 9 mBq. A sophisticated computer simulation was also created with the goal of obtaining
a better understanding of the experimental results and gamma–gamma coincidence efficiencies at different sample geometries.
Authors:Ian Hoffman, Kurt Ungar, Marc Bean, Jing Yi, René Servranckx, Calin Zaganescu, Nils Ek, Xavier Blanchard, Gilbert Le Petit, Guy Brachet, Pascal Achim, and Thomas Taffary
Radioxenon concentration data collected at International Noble Gas Experiment (INGE) monitoring sites in the Northern Hemisphere
are demonstrably impacted by emissions from medical isotope (MI) production facilities at Chalk River (CRL), Ontario and Fleurus,
Belgium [Saey, J Environ Radioact 100(5):396–406, 2009]. Temporary cessation at these European MI facilities in the latter
half of 2008 allowed an opportunity to assess the relative impact of distant MI facilities at INGE monitoring stations. In
particular, the concentration distributions at the measurement sites and calculated sensitivities to the putative emission
locations through atmospheric transport modelling (ATM) of meteorological Source Receptor Sensitivity (SRS) computations were
used to study MI impacts.