Carbon Capture Utilization and Storage (CCUS) technology is considered a mitigation measure to control the increasing CO2 emissions in atmosphere during energy transition. Even if CO2 infrastructures already exist in remote areas of USA and Europe, the CCUS facilities have to be deeply analyzed as safer systems, considering new issues strictly connected to their presence in more densely populated areas. As part of the Quantitative Risk Assessment, the critical transportation conditions and the released stream characteristics have been analyzed to assess the effects of an unexpected CO2 release event. The aim of this thesis is to fill the gaps of knowledge in the Quantitative Risk Assessment for dense phase CO2, for which consolidated and shared methods do not exist, due to limited use of this stream in traditional plants.