The simulation of prototype scanning systems for radiological waste applications holds paramount importance in modern waste management strategies, particularly concerning the so-called Swedish legacy waste (SLW) [1]. SLW, stemming from various sources including commercial, research, military, and medical sectors from the 1960s to the 1990s, presents unique challenges due to its diverse composition and packaging methods. Regulatory changes necessitate reconditioning of SLW to meet updated waste acceptance criteria for final repositories. However, the process is hindered by factors such as lacking documentation, concrete encapsulation, and the risk of breaching containment during handling. Consequently, there arises a critical need for non-destructive scanning methods to assess the internal structure of waste containers accurately. Simulation plays a crucial role in developing and optimizing such scanning systems, offering insights into system performance, parameter optimization, and scenario exploration. Utilizing simulation platforms like Geant4 [2], radiation interactions with SLW containers can be modelled, aiding in the design of efficient scanning methodologies. Moreover, simulations enable the evaluation of system robustness and efficacy under diverse conditions, ensuring safe handling and disposal of radioactive materials. Thus, the integration of simulation techniques in the development of prototype scanning systems presents a promising avenue for addressing the complexities associated with managing SLW, ultimately contributing to enhanced safety and environmental protection. References: [1] Anders Wiebert, Elisabet Höge, Pernilla Sandgren, Ulf Yngvesson, and Nina Cromnier, "Utredning avseende ansvar för historiskt avfall," Strålsäkerhetsmyndigheten (Swedish Radiation Safety Authority), 2022. [2] S. Agostinelli et al., "Geant4—a simulation toolkit," Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, vol. 506, no. 3, pp. 250-303, 2003. [Online]. Available: https://doi.org/10.1016/S0168-9002(03)01368-8. [Accessed: April 25, 2024].