PAULO ERNESTO DE OLIVEIRA LAINETTI
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Artigo IPEN-doc 23509 Decommissioning of uranium pilot plants at IPEN-CNEN/SP: facilities dismantling, decontamination and reuse as new laboratories for strategic programs2016 - LAINETTI, PAULO E. de O.; FREITAS, ANTONIO A. de; VASQUES, FRANCISCO M.F.; FERREIRA, ROBSON de J.; COTRIM, MARYCEL E.B.; PIRES, MARIA A.F.From beginning of 90’s, the Brazilian nuclear policy has been changed radically. This determined the interruption of most R&D fuel cycle activities and the facilities shutdown at Nuclear and Energetic Research Institute (IPEN). The existence of those facilities also implicated in the need of constant surveillance, representing additional obligations, costs and problems. The reasons to promote the dismantling of the IPEN’s Nuclear Fuel Cycle Pilot Plants elapsed mainly from the need of physical space for new activities, since the R&D in the nuclear fuel cycle area were interrupted. In the last decade, IPEN has changed its “nuclear profile” to a “comprehensive and multidisciplinary profile”. With the end of most nuclear fuel cycle activities, the former facilities were distributed in four different centers. Each center has adopted a different strategy and priority to face the D&D problem. The available resources depend on the specific program in each area’s development (resources available from other sources, not only from Brazilian National Nuclear Energy Commission (CNEN). One of those new activities is the IPEN’s Environmental Program. This paper describes the procedures, problems faced and results related to the reintegration of the former pilot plant areas as new laboratories of the Chemical and Environmental Technology CenterCQMA of the IPEN.Artigo IPEN-doc 23511 Use of dopants for thoria sintering temperature reduction-characterization of THO22016 - TAKIISHI, HIDETOSHI; GENOVA, LUIS A.; CAVALHEIRA, ELTON D.; COTRIM, MARYCEL B.; SANTOS, WILSON; LAINETTI, PAULO E.O.Thorium is nearly three times more abundant than uranium in the Earth’s crust. Some papers evaluate the thorium resources in Brazil over 1,200,000 metric t. These figures mean that the country is probably the biggest thorium resource in the world, with only part of the territory prospected. Nevertheless, Brazil has not a research program for use of thorium in nuclear reactors, even having dedicated special attention to the subject in the beginning of its nuclear activities, in the fifties and sixties. From 1985 until 2003 IPEN operated a pilot plant for thorium nitrate production and purification, used by Brazilian industry for production of gas mantles. This facility produced over 170 metric t of thorium nitrate. Despite the non-nuclear application, the pilot plant was unique in the southern hemisphere. On the other hand, Brazil has the biggest world niobium resources. The Brazilian thorium and niobium resources added to the predictable future importance of alternative fissile materials have motivated this research, since uranium is a finite resource if used in the present thermal nuclear reactors. Besides this, thorium oxide is an important nuclear reactor material. It is a refractory oxide and its ceramic fabrication process involves a very high temperature sintering treatment considering that thoria melting point is very high (3,650 K). Cations of elements of the group VB (V, Nb and Ta) have a known effect in the reduction of thoria sintering temperature. IPEN has initiated an investigation about the use of niobium as a dopant for thoria sintering temperature reduction. The thoria used in the research was produced in the IPEN’s pilot plant and different amounts of niobium oxide (Nb2O5) will be added to thoria by different routes. The powders will be compressed and the compacted pellets will be sintered at different temperatures. The influence of the different parameters in the density of sintered pellets is being investigated. This paper presents the chemical and physical characterization for the thoria used in the investigation.Artigo IPEN-doc 21077 Use of dopants for thoria sintering temperature reduction - characterization of ThOsub(2)2015 - TAKIISHI, HIDETOSHI; GENOVA, LUIS A.; CAVALHEIRA, ELTON D.; COTRIM, MARYCEL B.; SANTOS, WILSON R.; LAINETTI, PAULO E.O.Artigo IPEN-doc 12163 Reintegration of areas of the IPEN´S dismantled nuclear fuel cycle pilot plants as new laboratories of the CQMA2007 - LAINETTI, PAULO E.O.; COTRIM, MARYCEL E.B.; VASQUES, FRANCISCO M.F.; FERREIRA, ROBSON de J.; PIRES, MARIA A.F.