Summary
The document presents an advanced hybrid modeling capability for nuclear fuel performance using the PEGASUS code, combining 2D and 3D representations with Material Point Method (MPS) and explicit crack modeling. The approach embeds detailed 3D zones within coarser 3D mesh regions and links those to surrounding 2D zones to balance computational efficiency and resolution where fracture and localized behavior occur. A highlighted workflow shows a detailed 3D zone centered on an MPS region for high-fidelity simulation of crack initiation and propagation, flanked by course 3D mesh zones that transition to 2D zones at the model boundaries. This multi-scale hybridization permits explicit representation of cracks in the most critical regions while maintaining overall model tractability for fuel rods and assemblies. The capability targets nuclear fuel integrity analyses, enabling localized investigation of damage mechanisms within full-length fuel geometries. Structural Integrity Associates, Inc. positions this method within its Nuclear Fuel Technology offerings and provides contact information for further technical engagement. The visual emphasizes the nested zone strategy—detailed 3D/MPS core, coarse 3D transition, and 2D outer zones—illustrating how PEGASUS supports focused fracture mechanics studies embedded in broader fuel performance simulations.