In the pursuit of Carbon Capture and Storage (CCS) initiatives, the establishment of an extensive network of transportation pipelines, encompassing both on- and offshore domains, becomes paramount. A crucial aspect of ensuring the integrity of these pipelines is the assessment of running ductile fractures (RDF), a phenomenon in which defects evolve into cracks driven by pressure forces from escaping mixtures. While the Battelle Two-Curve Method (BTCM) is widely used for RDF assessment, it was originally designed for natural gas and proves inadequate for CO2 applications. Existing international guidelines, such as ISO 27913 and DNVGL-RP-F104, still rely on this method, resulting in uncertainties and potentially uneconomical designs due to excessive safety margins. This paper addresses the gap by introducing a cost-effective assessment approach utilizing a recently developed and validated Fluid-Structure Interaction (FSI) model. This model incorporates the coupled prediction of CO2 mixture decompression behavior during crack propagation in pipelines. Notably, the numerical FSI model accurately predicts results from different full-scale experiments, encompassing 3D decompression and crack arrest behavior in pipelines, both onshore and offshore. This advancement offers a promising path toward enhancing CO2 pipeline safety and facilitating the transition to sustainable energy solutions.