ALFREDO YUUITIRO ABE
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Artigo IPEN-doc 29914 Assessment of minimum allowable thickness of advanced steel (FeCrAl) cladding for accident tolerant fuel2023 - ABE, ALFREDO; GIOVEDI, CLAUDIA; MELO, CAIO; SILVA, ANTONIO T. eThe ferritic iron-chromium-aluminum (FeCrAl) alloy cladding is considered to be the most promising for near-term application in the ATF framework to replace existing zirconium alloy cladding. Although FeCrAl cladding presents several advantages, it is well known that there are at least two main drawbacks, one is the increased thermal neutron absorption cross-section compared to the current Zr-based cladding resulting in a neutronic penalty and another is tritium higher permeation. In the present study, the minimum allowable thickness of cladding is addressed considering neutronic penalty reduction and the mechanical-structural behavior under the LOCA accident condition. The neutronic penalty assessment was performed using the Monte Carlo code and mechanical-structural performance of the FeCrAl cladding using the TRANSURANUS fuel code, which was modified to consider properly the FeCrAl cladding.Artigo IPEN-doc 29620 Effectiveness of Ni-based and Fe-based cladding alloys in delaying hydrogen generation for small modular reactors with increased accident tolerance2023 - AVELAR, ALAN M.; CAMARGO, FABIO de; SILVA, VANESSA S.P. da; GIOVEDI, CLAUDIA; ABE, ALFREDO; MOURAO, MARCELO B.This study investigates the high temperature oxidation behaviour of a Ni–20Cr-1.2Si (wt.%) alloy in steam from 1200 °C to 1350 °C by Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and X-ray Diffraction (XRD). The results demonstrate that exposed Ni-based alloy developed a thin oxide scale, consisted mainly of Cr2O3. The oxidation kinetics obtained from the experimental results was applied to evaluate the hydrogen generation considering a simplified reactor core model with different cladding alloys following an unmitigated Loss-Of-Coolant Accident (LOCA) scenario in a hypothetical Small Modular Reactor (SMR). Overall, experimental data and simulations results show that both Fe-based and Ni-based alloys may enhance cladding survivability, delaying its melting, as well as reducing hydrogen generation under accident conditions compared to Zr-based alloys. However, a substantial neutron absorption occurs when Ni-based alloys are used as cladding for current uranium-dioxide fuel systems, even when compared to Fe-based alloys.Artigo IPEN-doc 27361 On the nuclear safety improvement by post-inerting small modular reactor with stainless steel cladding2020 - AVELAR, ALAN M.; MOURAO, MARCELO B.; MATURANA, MARCOS; GIOVEDI, CLAUDIA; ABE, ALFREDO Y.; PEDRASSANI, RAFAELA; SU, JIANAfter Fukushima Daiichi accident, the replacement of zirconium-based fuel cladding in Light Water Reactors (LWR) became one of the main challenges of the nuclear industry. Austenitic steel–clad presents some safety advantages comparing to zirconium alloys, noticeably, higher activation energy and lower enthalpy of metal-water reaction. Thus, it produces a slower hydrogen release into the containment following a postulated accident. In this study, a Loss-of-Coolant Accident (LOCA) aggravated by the complete failure of the Emergency Core Cooling System (ECCS) is analyzed for a Small Modular Reactor (SMR). Post-accident injection of inert gas into the containment is used as one of the hydrogen control systems, to enhance safety margins during Severe Accidents (SA). The inertization system is successful in complementing Passive Autocatalytic Recombiners (PAR) to perform combustible gas control.