OLANDIR VERCINO CORREA
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Artigo IPEN-doc 23403 Coatings to protect spent aluminium-clad research reactor fuel during extended wet storage2017 - FERNANDES, S.M.C.; CORREA, O.V.; SOUZA, J.A. de; RAMANATHAN, L.V.; ANTUNES, R.A.; OLIVEIRA, M.C.L. deConversion coatings have been used to protect aluminium surfaces from corroding. Hence use of this type of coating was considered to protect the aluminium cladding of spent research reactor fuels during extended wet storage. A conventional chemical process, as opposed to an electrochemical process, is preferred due to the shape of the fuel and its high radioactivity. In this context hydrotalcite (HTC) and boehmite coatings were considered. This paper presents the results of further development of HTC coatings, from the stand point of eventually being able to coat highly radioactive spent fuels using remote handling equipment. More specifically: (a) preparation of HTC coatings from different baths on AA 6061 alloy surfaces that were given pre-treatments to simulate spent fuel surfaces; (b) characteristics of the HTC coatings as a function of bath temperature; (c) corrosion behaviour of HTC coated AA 6061 alloy; (d) results of field studies in which dummy fuel elements, consisting of Al alloy plates coated with HTC from different baths (with or without post coating treatments), were immersed in the IEA-R1 reactor’s spent fuel basin for periods of up to 2 years. This study demonstrates that Al surfaces can be coated with HTC using an allroom temperature process. The field tests revealed marked increase in corrosion resistance of HTC coated plates. The mechanism of corrosion protection is discussed and a mock-up arrangement to remotely handle dummy-fuel elements to pre-treat, coat with HTC and post-treat is presented.Artigo IPEN-doc 14598 Lanthanide based conversion coatings for long term wet storage of aluminium-clad spent fuel2010 - FERNANDES, S.M.C.; CORREA, O.V.; SOUZA, J.A. de; RAMANATHAN, L.V.Spent fuels from research reactors are stored in basins with water of less than desirable quality at many facilities around the world and instances of cladding failure caused by pitting corrosion have been reported. Conversion coatings have been used in many industries to protect different metals, including aluminium alloys. This paper presents the results of an ongoing investigation in which the corrosion resistance of lanthanide (cerium, lanthanum and praseodymium) based conversion coated RR fuel cladding alloys has been studied. Electrochemical tests in the laboratory revealed higher corrosion resistance of CeO2, La2O3 and Pr2O3 coated AA 1100 and AA 6061 alloys in NaCl solutions. Uncoated and CeO2 coated coupons of these alloys exposed for 50 days to the spent fuel basin of the IEA-R1 research reactor in IPEN, Brazil, revealed marked reductions in the extent of pitting corrosion.Artigo IPEN-doc 18561 Hydrotalcite and Boehmite coatings for increased protection of Aluminum clad spent nuclear fuel2012 - FERNANDES, STELA M.C.; CORREA, OLANDIR V.; SOUZA, JOSE A. de; RAMANATHAN, LALGUDI V.It is essential to increase the corrosion resistance of Al-clad research reactor (RR) spent fuels during long term wet storage. Laboratory and field tests were carried out to evaluate the pitting corrosion resistance of rare earth containing conversion coatings on Al alloys, AA 1100 and AA 6061, used as cladding of RR fuel plates. These investigations were extended to include boehmite and hydrotalcite (HTC) coatings on Al alloy surfaces. Characterization of the coatings was done with the aid of SEM/FEG/EDS and x-ray diffraction analysis. The electrochemical behavior of uncoated and coated specimens was determined in 0.1 M NaCl. Field tests were carried out in which uncoated, lanthanide-based conversion coated, boehmite coated, cerium modified boehmite coated, HTC coated and cerium modified HTC coated Al alloy coupons were exposed to the IEA-R1 reactor spent fuel basin for varying periods and then their corrosion resistance evaluated. Most of the coatings increased the pitting corrosion resistance of the two alloys and among the coatings, the cerium modified HTC coating was the most efficient.Artigo IPEN-doc 19256 Protection od spent aluminium-clad research reactor fuels during extended wet storage2013 - FERNANDES, STELA M.C.; CORREA, OLANDIR V.; SOUZA, JOSE A .; ANTUNES, RENATO A.; OLIVEIRA, MARA C.L. de; RAMANATHAN, LALGUDI V.