JOSE ANTONIO BATISTA DE SOUZA
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Artigo IPEN-doc 26995 Coatings for safe long term wet storage of spent Al-clad research reactor fuels2015 - RAMANATHAN, L.V.; FERNANDES, S.M.C.; CORREA, O.V.; SOUZA, J.A. de; ANTUNES, R.A.; OLIVEIRA, M.C.L. dePitting corrosion of the aluminium cladding of spent research reactor (RR) fuels in wet storage has been observed and the use of conversion coatings to protect the cladding was proposed. A coating prepared by conventional chemical processing as opposed to electrochemical processing is the only option due to constraints related to the shape of the fuel and its high radioactivity. Hence, hydrotalcite (HTC) and boehmite were considered. This paper presents: (a) preparation of hydrotalcite (HTC) coatings from different baths followed by post-coating treatments; (b) corrosion behavior of HTC coated AA 6061 alloy; (c) results of field studies in which uncoated and HTC coated AA 6061 alloy coupons and plates, the latter assembled as a dummy fuel element, were exposed to the IEA-R1 reactor spent fuel basin for extended periods. The laboratory and field tests revealed marked improvements in the corrosion resistance of HTC coated specimens, coupons and plates. The mechanism of corrosion protection is presented.Artigo IPEN-doc 23971 Effect of temperature on corrosion and semiconducting properties of oxide films formed on M5 zirconium alloy2016 - ANTUNES, R.A.; OLIVEIRA, M.C.L. de; SOUZA, J.A.B. deNuclear fuel cladding for pressurised water reactors is commonly manufactured with zirconium alloys. The M5 alloy is a relatively new cladding material for in-reactor used with enhanced performance compared to traditional zircaloys. In this work, the influence of temperature on the corrosion resistance and semiconducting properties of the passive film formed on the M5 alloy in a borate buffer solution has been evaluated. The electrochemical behaviour of the zirconium alloy was assessed by potentiodynamic polarisation tests, electrochemical impedance spectroscopy and Mott–Schottky plots. The results indicated that the corrosion resistance of the M5 alloy decreased with temperature due to the formation of a less stable and more defective passive film. The Mott–Schottky approach used in combination with polarisation tests and impedance measurements was effective to reveal the protective state of the passive film on the M5 alloy.