<p>The Prompt Gamma-ray Activation Analysis (PGAA) technique is a highly sensitive and non-destructive approach for multi-elemental analysis based on neutron capture and prompt gamma emission. At the Moroccan TRIGA MARK II reactor, the sustained use of the PGAA system necessitates an integrated evaluation of neutron-induced activation, dose distribution, and mechanical aging of key components. In this study, detailed Monte Carlo simulations using the PHITS code were coupled with finite element mechanical modeling in COMSOL Multiphysics to assess the radiological and structural response of the steel collimator, multilayer shutter, and sapphire filter under realistic irradiation conditions. The results reveal persistent residual radioactivity within the steel collimator—dominated by long-lived isotopes such as ⁵⁵Fe and ⁵⁴Mn—while activation in the shutter remains moderate but spatially confined to steel interfaces. Dose maps exhibit pronounced axial confinement and steep radial gradients associated with localized material activation. Mechanical stress analysis identified significant elastic strain concentrations at steel–lead–Mirrobor interfaces during shutter operation, indicating potential fatigue zones. These findings provide an integrated understanding of the coupled radiological–mechanical aging mechanisms governing the long-term performance, reliability, and safety of PGAA systems, and offer a foundation for optimized design and maintenance strategies.</p>