Surrogate Modeling for Neutron Transport: A Neural Operator Approach

This work introduces a neural operator–based surrogate modeling framework for neutron transport computation. Two architectures, the Deep Operator Network (DeepONet) and the Fourier Neural Operator (FNO), were trained for fixed source problems to learn the neutron transport governing equation to predict angular fluxes based on anisotropic neutron sources, in a one-dimensional slab geometry. Three distinct models were trained for each neural operator, corresponding to different scattering ratios (c= 0.1, 0.5, and 1.0), providing insight into their performance across distinct transport regimes (absorption-dominated, moderate, and scattering-dominated). The models were subsequently evaluated on a wide range of previously unseen source configurations, demonstrating that FNO generally achieves higher predictive accuracy, while DeepONet offers greater computational efficiency. Both models offered significant speedups that become increasingly pronounced as the scattering ratio increases, requiring