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       Project Proposal DESMET refers to characterization of radioactive waste consisting on the identification and measurement of radioactive content, in order to evaluate and reduce the radioactive risks on short and long term, for the environment and public.
       Thus, the main goal of the project is the characterization of the radioactive waste, leading to the full knowledge of the radionuclides inventory. Nondestructive methods are used for so called radionuclides easy to be measured (gamma emitters), whereas by destructive methods the measurement of the full radionuclides inventory (alpha, beta and gamma emitters) is accessible.
       The management of radioactive waste has to be done in conformity with the requirements of national standards and regulations for the nuclear security, protection of professionally exposed workers, population, environment and property, respecting also the international treaties in which Romania participates.
       Based on its prerogatives given by the Law 111/1996, republished in 1998, supplemented and changed by the Law 193/2003, the National Commission for Nuclear Activities Control (CNCAN) issued during in the last years a set of normative settlement concerning the safety of nuclear activities in Romania, according to IAEA recommendations and European Commission directives.
       The safe management of radioactive waste has to be done according to the guidelines of the National Strategy on medium and long term for the management of spent nuclear fuel and radioactive waste resulted from the operation of research reactors and decommissioning of nuclear installations, from their production to the final disposal.
       The characterization of radioactive waste has to be done during their production, collecting, sorting, conditioning and their transport inside the nuclear unit, as well as related to the external transport for their final disposal. The key information necessary for the characterization of the radioactive waste include: types of waste; key radionuclides present in the waste; dose rate; presence of (aqueous or organic) fluids; presence of corrosive agents, potential of developing problematical chemical and/or biological reactions; important physical properties (e.g., density, state of aggregation etc); and heterogeneous character of the any of the above mentioned characteristic.
       In order to characterize the radioactive waste and the spent nuclear fuel the use of both nondestructive and destructive investigation methods are to be considered. By the nondestructive methods only the activity of gamma emitting radionuclides can be measured, whereas by the destructive methods the activity of alpha, beta and gamma emitters can be measured.
       A comparative study of the strategies and practical approaches in different countries indicates the variety of the methods used to reach the same goals. The insufficient harmonization of testing methods, and different interpretation of the measurement results, especially in the area of quality control of the waste final forms and packages, require the application of a set of rules somehow unified, according to IAEA requirements.
       The radionuclides which are mainly present in waste, having to be measured, are: Ni-59, Ni-63, Co-60, Sr-90, Nb-94, Tc-99, I-129, Cs-137, U-234, U-235, U-238, Pu-238, Pu-239, Pu-240, Pu-241, Am-241.These radionuclides are associated to a high radiological risk for the public health and environment. They can be found in the radioactive waste resulted from the irradiation activities performed in research reactor, mainly due to the external contamination with uranium of fuel element sheath. Uranium is subject the same processes as the fuel inside the fuel element sheath. In this way, fission products and transuranium elements can be produced. They will be collected by the moderator agent and then retained on exchange ions resins used in the purification process.
       Another possible source of contamination, but less probable, is the fuel element cracking when part of the radionuclides inventory migrates outside the fuel element and are dissolved by the moderator agent. The moderator agent is continuously subjected to purification process, the contaminants being retained by the exchange ions resins. The post-irradiation examination of the spent fuel leads also to the production of radioactive waste (the so-called “technological radioactive waste”).