|Abstract English (optional):
Radioxenon is mainly produced as fission product by nuclear power plants but also by spontaneous fission of transuranic isotopes as Pu-240. Xe is a noble gas characterized by chemical inertia and high mobility in the underground so it could be of interest for the monitoring of Pu-240 in the wastes, given its high yield of spontaneous fission and its constant production rate. The release of radioxenon could impact the isotopic composition of the total xenon outgassing form the subsurface giving an early warning signal of leakage form transuranic wastes. Pu-240 is actually present in the Italian radioactive waste inventory, with a total activity of about 200GBq. In Italy there was only one facility that perform analysis of radioactive isotopes of xenon in the atmosphere and it is hosted by ENEA, the Italian National Agency for New Technologies, Energy and Sustainable Economic. ENEA traceability Laboratory performs radiometric controls and assessments of radioactive contamination in several kinds of different samples: environmental samples as air (Atmospheric Particles and Dissolved Noble Gas), water (Sea, River and Lagoon) and sediments soils vegetables; industrial samples as building materials tiles (floor and walls) and metals fuels check for decommissioning of power plants; food samples as milk, water (Drinking), cereals, wine, meat, vegetables and so on. ENEA Noble Gas laboratory is also supporting activities of the Italian National Data Centre for the Comprehensive Test Ban Treaty (CTBT), participating since four years to the RadioXenon Intercomparison exercises. The development of an "early warning" tool or the identification and management of eventual nuclear accidents and the monitoring and control of the repository for the storage of radioactive wastes have been included in the research activities of ENEA Traceability laboratory. The methodology for the noble gas monitoring in the proximity of a radioactive waste disposal, to better understand the origin of xenon emission will be presented.