This report documents a week-long measurement campaign conducted on six, dry-storage, spentnuclear-fuel storage casks at the Idaho National Laboratory. A gamma-ray imager, a thermalneutron imager and a germanium spectrometer were used to collect data on the casks. The campaign was conducted to examine the feasibility of using the cask radiation signatures as unique identifiers for individual casks as part of a safeguards regime. The results clearly show different morphologies for the various cask types although the signatures are deemed insufficient to uniquely identify individual casks of the same type. Based on results with the germanium spectrometer and differences between thermal neutron images and neutron-dose meters, this result is thought to be due to the limitations of the extant imagers used, rather than of the basic concept. Results indicate that measurements with improved imagers could contain significantly more information. Follow-on measurements with new imagers either currently available as laboratory prototypes or under development are recommended.ii
SUMMARYIn October and November 2012 the INL Compton Dry-Cask Imaging Scanner (CDCIS) was packaged and transported to the Doel Nuclear Power Plant near Antwerp, Belgium to perform a series of measurements on spent fuel storage casks. The task was performed in support of the DOE/NNSA NA-241 IAEA request 09/TAU-10 Restoration of CoK of LWR Fuel Assemblies by Gamma Scanning from the Top of Casks. The purpose of the measurements was to determine whether the system could by passive detection of the gamma rays being emitted by the contained spent fuel, confirm the presence or absence of the nuclear fuel bundles in a known, verified dry storage cask. If successful, the system, would be used to confirm the presence of the nuclear fuel bundles on four casks in storage that had lost continuity of knowledge due to problems verifying the status of the casks' Tamper Indicating Device (TID) seals.Although proof of principle testing at INL on the Westinghouse MC-10 cask demonstrated the ability of the CDCIS to detect empty vs. full storage positions in the cask, and MCNP modeling indicated that the Doel casks should have sufficient decay energy to detect fission and activation product gamma ray peaks, the presence of a thick steel ballistic shield on the Belgian casks scattered the gamma energy to such an extent that discrete peaks were not able to be identified, truncating the test without being able to distinguish the empty-full status of the casks. viii ix ACKNOWLEDGEMENTS
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