Stellarator Design Exploration Using Symbolic-Regression Neutronics Surrogates

Miralles-Dolz, Enrique [Princeton Plasma Physics Laboratory, Princeton, USA] (ORCID:0000000321356084); Churchill, Michael [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)] (ORCID:000000015711746X); Schwartz, Jacob [Marathon Fusion, San Francisco, CA (United States)]; Hidalgo-Salaverri, Javier [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)]; Moreno, Connor [Univ. of Wisconsin, Madison, WI (United States)]; Bohm, Tim [Univ. of Wisconsin, Madison, WI (United States)]; Wilson, Paul [Univ. of Wisconsin, Madison, WI (United States)] (ORCID:0000000285554410)

doi:10.1109/tps.2026.3680528

DOE OSTI · 3030191

Stellarator Design Exploration Using Symbolic-Regression Neutronics Surrogates

Miralles-Dolz, Enrique [Princeton Plasma Physics Laboratory, Princeton, USA] (ORCID:0000000321356084)·Churchill, Michael [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)] (ORCID:000000015711746X)·Schwartz, Jacob [Marathon Fusion, San Francisco, CA (United States)]·Hidalgo-Salaverri, Javier [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)]·Moreno, Connor [Univ. of Wisconsin, Madison, WI (United States)]·Bohm, Tim [Univ. of Wisconsin, Madison, WI (United States)]·Wilson, Paul [Univ. of Wisconsin, Madison, WI (United States)] (ORCID:0000000285554410)

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Abstract

Systems codes require fast, simplified models to rapidly evaluate fusion power plant concepts, but neutronics analyses are often a computational bottleneck. Here, to address this, surrogate models for key neutronics responses have been developed using 3-D neutronics-ready models built with the open-source code ParaStell from a database of stellarator equilibria. Neutronics responses such as tritium breeding ratio (TBR), nuclear heating, and neutron-induced radiation damage displacements per atom (dpa) were simulated using OpenMC. Through sensitivity analysis and symbolic regression (SR), simple power-law formulas were derived connecting these neutronics responses to global stellarator parameters, including fusion power, plasma surface area, and plasma elongation. Validation shows these formulas can predict the simulation results with low error, enabling quick and accurate assessment of neutronics requirements in stellarator design exploration activities with systems codes.

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Miralles-Dolz, Enrique [Princeton Plasma Physics Laboratory, Princeton, USA] (ORCID:0000000321356084), Churchill, Michael [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)] (ORCID:000000015711746X), Schwartz, Jacob [Marathon Fusion, San Francisco, CA (United States)], Hidalgo-Salaverri, Javier [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)], Moreno, Connor [Univ. of Wisconsin, Madison, WI (United States)], Bohm, Tim [Univ. of Wisconsin, Madison, WI (United States)], Wilson, Paul [Univ. of Wisconsin, Madison, WI (United States)] (ORCID:0000000285554410). 2026-04-16. Stellarator Design Exploration Using Symbolic-Regression Neutronics Surrogates. https://doi.org/10.1109/tps.2026.3680528

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