Interactive Geometry Visualisation and Verification in Serpent 2: Development and Integration of a 2D/3D Plotter as Part of the Kraken Framework

The scope and fidelity of Monte Carlo transport-based reactor physics simulations have expanded significantly through advances in transport methods and increasing computational resources. Complex three-dimensional models are now routinely applied in fusion neutronics, activation and shielding analysis, and radiation protection. In such applications, complex and often CAD-derived geometries must be verified reliably to ensure correspondence between the simulated and intended physical model.

Traditional file-based plotting utilities in most Monte Carlo transport codes provide static two-dimensional views that are adequate for basic inspection but offer limited interactivity and cannot effectively convey the internal structure of complex three-dimensional configurations. As model fidelity increases, these limitations hinder efficient and systematic geometry verification.

In this thesis, an interactive two- and three-dimensional visualisation tool for the Serpent Monte Carlo particle transport code was developed and integrated into the Kraken framework. The two-dimensional views utilise the existing Serpent plotting capability extended with interactive control, while three-dimensional views are generated using a ray-based rendering approach implemented directly within Serpent transport routines. A graphical user interface enables real-time manipulation of view orientation, slicing and rendering parameters. Because the rendering reuses the same geometry representation as particle tracking, the produced images remain consistent with transport behaviour without intermediate geometry conversion or post-processing.

The developed tool was evaluated using geometrically intricate test cases representative of high-fidelity fission and fusion applications. The results demonstrate that interactive two- and three-dimensional visualisation can be achieved with good computational performance while maintaining consistency with the transport model. Integration into the Kraken framework provides a unified execution environment for practical deployment in modern reactor analyses using Serpent. The implementation establishes a reliable and extensible framework for geometry verification within advanced Monte Carlo–based reactor physics simulations.