SCALE Methodology for Spatially Based Activation of Materials for Transportable Microreactor Applications

This study introduces an innovative methodology for spatially-based activation of materials, with a
particular focus on addressing the challenges posed by extreme neutron flux variations in environments
such as the ground surrounding transportable microreactors. In contrast to the conventional approach within
the SCALE framework, which relies on averaging neutron flux across materials, this paper presents a new
methodology that leverages neutron flux mesh tallies and voxel-specific material irradiation. After determining the
neutron flux distribution, materials are irradiated spatially, with each voxel (3D geometric cell) receiving its own
neutron flux. This comprehensive approach leads to the creation of a distributed photon flux source derived from
nuclide decay for subsequent dose calculations. The significance of this research lies in its ability to accurately
capture
the complex spatial distribution of neutron flux in ground environments, a crucial aspect for the
design and safety evaluation of transportable microreactors. This methodology ensures that materials are
irradiated spatially by the neutron flux based on actual positions, further enhancing the
ability to model the environmental impact of transportable microreactors. The proposed approach
was validated through a comparison with the standard SCALE approach, demonstrating its precision
within acceptable uncertainties. This research paves the way for more accurate safety assessments
and informed decision-making in the deployment of transportable microreactors, contributing to the sustainable
expansion of nuclear energy solutions.