Neutron Cross-Section Uncertainty and Reactivity Analysis in MOX and Metal Fuels for Sodium-Cooled Fast Reactor

This study presents a comprehensive uncertainty and sensitivity analysis of the effective neutron multiplication factor (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>k</mi><mi>eff&...

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Bibliographic Details
Main Author: Oyeon Kum
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Atoms
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Online Access:https://www.mdpi.com/2218-2004/13/5/41
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Summary:This study presents a comprehensive uncertainty and sensitivity analysis of the effective neutron multiplication factor (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>k</mi><mi>eff</mi></msub></semantics></math></inline-formula>) in a large-scale sodium-cooled fast reactor (SFR) modeled after the European Sodium Fast Reactor. Utilizing the Serpent Monte Carlo code and the ENDF/B-VII.1 cross-section library, this research investigates the impact of cross-section perturbations in key isotopes (<sup>235</sup>U, <sup>238</sup>U, and <sup>239</sup>Pu for both mixed oxide (MOX) and metal fuels. Particular focus is placed on the capture, fission, and inelastic scattering reactions, as well as the effects of fuel temperature on reactivity through Doppler broadening. The findings reveal that reactivity in MOX fuel is highly sensitive to the fission cross sections of fissile isotopes (<sup>239</sup>Pu and <sup>238</sup>U, while capture and inelastic scattering reactions in fertile isotopes such as <sup>238</sup>U play a significant role in reducing reactivity, enhancing neutron economy. Additionally, this study highlights that metal fuel configurations generally achieve a higher (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>k</mi><mi>eff</mi></msub></semantics></math></inline-formula>) compared to MOX, attributed to their higher fissile atom density and favorable thermal properties. These results underscore the importance of accurate nuclear data libraries to minimize uncertainties in criticality evaluations, and they provide a foundation for optimizing fuel compositions and refining reactor control strategies. The insights gained from this analysis can contribute to the development of safer and more efficient next-generation SFR designs, ultimately improving operational margins and reactor performance.
ISSN:2218-2004