Comparative analysis of Geant4 and MACCS for nuclear accident assessment in Saudi Arabia

Nuclear energy is increasingly being considered as a means to diversify energy sources in the Gulf region. The United Arab Emirates already operates nuclear power plants, while Saudi Arabia is pursuing its own nuclear program to reduce dependence on fossil fuels. The introduction of nuclear energy requires strong safety measures and reliable methods to evaluate the consequences of potential accidents to ensure preparedness at both national and regional levels. This study examines two commonly used tools for nuclear accident assessment: Geant4, a particle transport simulation framework based on the Monte Carlo method, and MACCS, which evaluates large-scale consequences for regulatory purposes. The Barakah Nuclear Power Plant in the UAE, near the Saudi border, is used as a case study to explore potential cross-border effects. Four key radionuclides – Iodine-131, Cesium-137, Strontium-90, and Xenon-133 – were analyzed. Using NOAA HYSPLIT with GDAS meteorological data, a hypothetical 10 % reactor core release was simulated. Results indicate that 131 I and 137 Cs could exceed safety limits, with the plume potentially reaching Abu Dhabi in 9–15 h and Riyadh in 42–54 h. These findings highlight the need to integrate detailed simulations with policy-focused modeling to guide emergency planning.