https://doi.org/10.1051/epjn/2026013
Regular Article
Impact of silicon on neutronic performance and microstructural evolution of FeCrAl alloys for ATF cladding
1
Research Center for Nuclear Reactor Technology, Research Organization for Nuclear Energy, National Research and Innovation Agency, BJ Habibie Integrated Science Area Building No. 80, Serpong, Tangerang Selatan 15312, Indonesia
2
Department of Physics, Faculty of Mathematics and Natural Sciences, Indonesian Defense University, IPSC Area, Sentul, Bogor, Indonesia
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Received:
27
October
2025
Received in final form:
27
April
2026
Accepted:
12
May
2026
Published online: 26 June 2026
Abstract
FeCrAl alloys are promising candidate for accident tolerant fuel (ATF) cladding in light water-cooled nuclear reactors (LWRs) due to their excellent high-temperature oxidation resistance and mechanical strength. This study investigates the effect of silicon (Si) additions (0–8.00 wt.%) on the neutronic performance and microstructural evolution of FeCrAl alloys through combined Monte Carlo simulations and experimental characterization. Neutronic behavior was evaluated using OpenMC on an AP1000 pressurized water reactor assembly model, while microstructural and mechanical properties were assessed via optical microscopy, SEM/EDS, XRD, and Vickers hardness testing. The results show that incorporating Si slightly improves the neutron economy of FeCrAl cladding by reducing Fe content, though the infinite multiplication factor (kinf) remains lower than that of Zr-4, limiting fuel discharge to ∼830 days compared to ∼1160 days for Zr-4. Experimentally, increasing Si content refined the average grain size from ∼498 μm (0 wt.% Si) to ∼201 μm (8.00 wt.% Si), accompanied by a linear increase in hardness from ∼280 HV to ∼520 HV. XRD analysis confirmed lattice parameter shifts consistent with Si incorporation, while SEM/EDS revealed generally uniform elemental distribution with localized Si segregation at higher concentrations. These findings highlight a trade-off: Si enhances microstructural stability and mechanical performance but only partially mitigates the neutronic penalty of FeCrAl. Optimizing Si content in conjunction with reduced cladding thickness is proposed as a pathway to balance neutronic efficiency with mechanical robustness for ATF deployment.
© I.W. Ngarayana et al., Published by EDP Sciences, 2026
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
