PAULO ERNESTO DE OLIVEIRA LAINETTI
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Artigo IPEN-doc 23510 Molten salts as stripping media for radioactive superficial decontamination2016 - LAINETTI, PAULO E. de O.The main practical difficulty associated to the task of the dismantling and decommissioning of the IPEN’s old nuclear fuel cycle facilities has been the big amount of radioactive waste generated in the dismantling operations. The waste is mainly in the form of contaminated carbon steel structures. In the IPEN, the presence of contamination in the equipments, structures and buildings, although restricted to low and medium activity levels, constituted an important concern due, on one hand, to the great volume of radioactive wastes generated during the operations. On the other hand, it should be outstanding that the capacity of radioactive wastes stockpiling in IPEN found been exhausted. In function of the large waste volume generated in the dismantling operations, the main concerns and focuses of research and technological development in the IPEN’s Chemical and Environmental Center—CQMA have been the effluent and waste treatment subjects, besides the development of some special decontamination techniques, since most old nuclear fuel cycle facilities are installed in the CQMA’s area. The reduction of the radioactive waste volume has a significant impact in the decommissioning costs and in the amount of material to be stored. The mentioned steel structures, during the operations and after ten or twelve years after the facilities shut down, have presented severe corrosion. In the past, to protect them, several layers of paint were applied. Traditional decontamination methods were tried, such as acid pickling, alkaline washing and ultrasonic baths. Nevertheless, these methods have failed to reach effective decontamination. In this paper, we described some aspects and problems in decommissioning of IPEN’s nuclear fuel cycle facilities and it is presented an innovative method for radioactive superficial decontamination of steel structures using different molten salt compositions and temperatures as stripping media.Artigo IPEN-doc 23505 Cutting techniques for facilities dismantling in decommissioning projects2016 - LAINETTI, PAULO E.O.Fuel cycle related activities were accomplished in IPEN-CNEN/SP in laboratory and pilot plant scale and most facilities were built in the 70-80 years. Nevertheless, radical changes of the Brazilian nuclear policy in the beginning of 90’s determined the interruption of several fuel cycle activities and facilities shutdown. Some laboratory and pilot plant decommissioning activities have been performed in IPEN in the last years. During the operational activities in the decommissioning of old nuclear fuel cycle facilities, the personnel involved in the task had to face several problems. In old facilities, the need of large components dismantling and material removal use to present some difficulties, such as lack of available and near electricity supply. Besides this, the spread out of the superficial contamination in the form of dust or aerosols and the exposure of workers should be as much as possible avoided. Then, the selection and availability of suitable tools for the task, mainly those employed for cutting and segmentation of different materials is of significant importance. Slight hand tools, mainly those powered by rechargeable batteries, facilitate the work, especially in areas where the access is difficult. Based on the experience in the dismantling of some old nuclear facilities of IPEN-CNEN/SP, some tools that would have facilitated the operations were identified and their availability could have improved the quality and efficiency of different individual tasks. In this paper, different cutting problems and techniques, as well as some available commercial hand tools, are presented as suggestion for future activities.