Research for establishment of method and design, production of a measurement system for assay activity and activity distribution of gamma emitting radionuclides in the waste drum by tomography gamma scanning technique

During the radioactive waste management stages including pre-disposal and disposal solid radioactive wastes, it is necessary to determine the radionuclide composition and their radioactive contained in the waste drums. Tomography Gamma Scanning measurement technique (TGS) for radioactive activity determination of radioactive waste packages is a new technique that provides highly accurate and reliable analytical results for waste packages with heterogeneous distribution of material density, composition radioisotopes and activity are compared with other nondestructive measurement techniques. This report presents the results of research on method development and spep-by-step design and production of a measurement system to determine the activity and activity distribution of gamma emitting radioisotopes for solid radioactive waste materials with low to moderate density contained in 200 liter drums by Tomography Gamma Scanning technique. TGS is a combination of Computed Tomography (CT) and Single Photon Emission Computed Tomography (SPECT) techniques. The TGS analysis, combining the data from the transmission and emission maps, results in a very accurate transmission correction for the determination of the activity and activity distribution in each scan layer and whole drum. The theme has achieved major results such as successfully establishment a method for TGS technique, the process of giving results is done manually with existing equipment; step by step design and manufacture automatic TGS system: mechanical system that scans waste drums in 3D space, digital multi-channel analyzer based on FPGA for HPGe detector, high voltage modul,... With the results achieved, the design and production of the TGS system is continuing to be perfected for application at the Dalat Nuclear Research Institute, Vietnam. (author)