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The Chornobyl catastrophe left a “contaminated legacy” that is hard to see and to measure. Around the Chornobyl Nuclear Power Plant (ChNPP) there is the Chornobyl Exclusion Zone (ChEZ) with a total area of about 2,400 km² that was created after the accident. In total, nine radioactive waste temporary storage places (RWTSP) hold a large of contaminated material that result from clean-up operations in the first months after the accident. Moreover, radioactive waste has been emplaced in three radioactive waste disposal sites (RWDS). The RWTSP and RWDS are located inside the higher contaminated central area of the ChEZ in the vicinity of the ChNPP.  Around 800 burials - trenches and/or clamps - are located in the RWTSP and contain radioactive material such as soil, plants or building rubble. Because the burying of the radioactive material had to happen in a short time and under accident liquidation conditions, a complete documentation of the volumes, the radionuclide inventories, and the exact positions of the trenches and clamps is unknown. The trenches and clamps have only been covered with a clean soil layer varying between 0.1 to 0.5 m thickness. No segregation of the buried material or construction of engineered barriers at the sites has been undertaken. The present publication summarizes new developments for airborne geophysical survey technologies and their testing that were performed in the Chornobyl Exclusion Zone. These field tests show remote sensing technologies combined with unmanned air vehicles as carrier and digital processing focussing primarily to map digitally terrain, trenches and clamps in the area of ‘Radioactive Waste Storage Places’ (RWSP) created shortly after the accident. Gamma-spectrometry mapping with an octocopter that in real time mode shows the contamination and can define the location even of the illegal burials was tested. The data processing comprises the assessment of possibility to identify unknown trenches and clamps from data obtained from remote sensing as to use them for refined safety assessments and management plans for RWSP.

UAV based technologies; optocopter; airborne survey; gamma spectrometry