Abstract: Accurate radiation safety evaluation is essential for the safe transportation and storage of spent nuclear fuel. Conventional approaches, which rely primarily on surface dose measurements or simplified models, often fail to account for the complex particle composition, energy spectra, and spatial flux distribution of highly radioactive spent fuel modules. This study employs the Geant4 Monte Carlo simulation toolkit to analyse the shielding performance of composite materials designed for spent nuclear fuel casks. We validate Geant4’s gamma attenuation predictions against EpiXS data in the energy range 0.1-20 MeV, comparing linear attenuation coefficients and half-value layer (HVL) values for candidate materials. Simulations are performed under environmental conditions representative of Rooppur Nuclear Power Plant in Bangladesh. The results show that the composite designs achieve shielding performance comparable to or superior to conventional materials, with improved reliability and optimized weight. Geant4 predictions closely match EpiXS data across tested energies, demonstrating Geant4’s suitability for detailed radiation safety evaluations in spent nuclear fuel cask design. These findings guide advanced, weight-efficient shielding strategies to enhance safety and cost-effectiveness in nuclear fuel storage and transportation. Deviations between Geant4 and EpiXS results remained within ±2%, confirming strong computational accuracy and supporting the design’s potential for enhanced shielding performance and mass optimization.

Keywords: Spent Nuclear Fuel, Composite Shielding, Geant4, Monte Carlo Simulation, EpiXS, Gamma Attenuation, Neutron Shielding, Linear Attenuation Coefficients, Half-Value Layer (HVL)

Pages: 111-119

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