Quantitative risk assessment of fuel preparation room having high-pressure fuel gas supply system for LNG fuelled ship

This paper systematically investigates the safety of fuel preparation room containing high pressure fuel gas supply systems in order to identify shortcomings and practical gaps of the current regulations. A very large ore carrier of 300,000 DWT was taken as an example and the LNG fuel system was designed for it. An event tree analysis was conducted on the fuel system to identify events that can lead to an explosion. Along with a fault tree analysis model, generic failure data from various sources were used to estimate frequency of potential explosion. For the consequence analysis computational fluid dynamics and finite element analysis software were used to estimate the impact of explosions on the boundary structure of the fuel preparation room. Research findings show that the current rules and regulations concerning the safety of fuel preparation rooms and that the high pressure fuel gas supply system is subject to an unacceptably high level of explosion risk with the frequency of explosion as high as 3.13E-04 per year. The impact of an explosion within the fuel preparation rooms can cause stresses in excess of allowable stress in the bottom structure if not being strengthened. It is proposed that special attention is given to the structural design and/or enhanced safe measures for the FPRs and the relevant regulations updated to account for this