Effectiveness of Ni-based and Fe-based cladding alloys in delaying hydrogen generation for small modular reactors with increased accident tolerance

• Published in: Nuclear engineering and technology 2023, 55(1), , pp.156-168
• Main Authors: Avelar, Alan Matias, de Camargo, Fábio, da Silva, Vanessa Sanches Pereira, Giovedi, Claudia, Abe, Alfredo, Mourão, Marcelo Breda
• Format: Article
• Language: English
• Subjects: Accident tolerant fuel cladding; Fuel cladding; High-temperature oxidation; Hydrogen generation; Nickel alloys; Stainless steel; 원자력공학
• ISSN: 1738-5733; 2234-358X
• DOI: 10.1016/j.net.2022.09.002

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. •Quartic oxidation kinetics of NiCr alloy was observed in short-term high temperature oxidation by steam.•NiCr met the ATF criteria of 100x improvement compared to Zr-based alloys in oxidation resistance.•Cladding heat-up rates were significantly lower for Fe-based and Ni-based alloys compared to Zr-based alloys.•Fe-based alloys reduce hydrogen generation rate and delay cladding melting compared to Zr-based alloys.