Novel Applications of State-of-the-Art Gamma-Ray Imaging Technique: From Nuclear Decommissioning and Radioprotection to Radiological Characterization and Safeguards

Gamma-ray imaging is a powerful technique subjected to important research efforts in nonmedical fields, providing information about the possible spatial distribution of radioactive materials emitting photons and potential contamination spots, in generic area survey or to specific component analyses. This capability opens up a range of possible applications in nuclear installations and radioactive waste management sites, where radiation survey protocols and radiological characterization of items may be highly and positively impacted by this technique. In this work, a new-generation 3-D pixelated CdZnTe gamma-ray imaging and spectrometry detector has been used in the context of the TRIGA RC-1 Research Reactor at the ENEA Casaccia Research Centre to test several applications where gamma-ray imaging can provide valuable information otherwise unknown (with equivalent level of accuracy and effort). Experiments carried out range from radiological survey, where hotspots are identified and radioactive items are sorted from conventional waste to improvements in the quantification of gamma emitters via gamma-spectrometry analysis, and from safeguards and nonproliferation purposes (e.g., providing methods to assess the amount of special nuclear material (SNM), which remains fixed and unchanged in time) up to radiation protection issues (e.g., identification of unexpected contributions to personnel total exposure). The results obtained in this experimental campaign, as well as the validations provided by comparison with "traditional" methods, demonstrate the applicability of state-of-the-art gamma-ray imaging systems to the presented tasks, with consequences that could positively impact the current radiation survey routines and radiological characterization protocols followed at ENEA TRIGA RC-1 as well as other installations.