Full-core design of helical cruciform fuel for power uprate in water-cooled SMRs
Year: 2026
Type: article
Abstract: Helical cruciform fuel (HCF) has been proposed as an advanced fuel design for water-cooled reactors, offering enhanced safety margins through increased heat transfer area and the potential for higher core power density compared with standard cylindrical fuel. However, comprehensive full-core neutronics design studies of HCF remain limited, particularly those exploring power uprates across different fuel forms. The unique helical geometry presents challenges for traditional two-step lattice homogenization approaches, motivating the use of direct three-dimensional full-core simulation. In this work, continuous-energy Monte Carlo simulations using the Serpent code are employed to perform a design study of three core configurations: a UO2 cylindrical fuel core, a U-50Zr HCF core, and a UO2 HCF core. The core design methodology is established and then applied to design U-50Zr and UO2 HCF cores with consistent core dimensions and operating conditions. A comprehensive comparison is performed across all three configurations, evaluating key design parameters for the equilibrium cycle such as core reactivity, critical boron letdown, power peaking factors, and reactivity coefficients. The cost assessment demonstrates that the HCF-enabled uprated core design is economically competitive with the reference design. This study provides the first direct three-dimensional Monte Carlo core design of a water-cooled small modular reactor employing HCF for power uprate, integrated with fuel performance and economic assessment.
Source: Nuclear Engineering and Design
Authors: Youyeon Choi, Koroush Shirvan
Institution: Massachusetts Institute of Technology
Language: English
Subfield: Aerospace Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $2,710
Award: G9000385829
OpenAlex ID: W7213979064