Consequence Assessment of the BBC Hydrogen Refueling Station, Using the ADREA-HF Code

Within the framework of the internal project HyQRA of the HYSAFE NoE, funded by EC, the participating partners were requested to apply their quantitative risk assessment (QRA) methodologies on an agreed predefined hypothetical gaseous hydrogen fueling station, the BBC station (Benchmark Base Case). The overall aim of the HyQRA was to perform an inter-comparison of the various QRA approaches and identify any knowledge gaps on data and information used in the QRA steps specifically related to hydrogen. Within this internal project, partners NCSRD and UNIPI collaborated on a common QRA. UNIPI identified the hazards on site, selected the most critical ones, defined the events that could be the primary cause of an accident and provided to NCSRD the scenarios listed in risk order for the evaluation of the consequences. NCSRD performed the quantitative analysis using the ADREA-HF CFD code. The predicted spatial and transient evolution of the formed flammable hydrogen-air clouds in the realistic geometry were provided to UNIPI for analysis of the consequences and evaluation of the risk and distances of damage to suggest improvements in the design and management of the BBC station to reduce the risk. In total fifteen scenarios were simulated. The firstfive were hydrogen releases in confined ventilated environment. Three scenarios concerned leaks inside the compression building, a small leak, a large leak and a pipeline rupture (initial flow rates0.0114 kg/s, 0.0456 kg/s and 1.14 kg/s respectively), under 150 ACH mechanical ventilation conditions. Two scenarios concerned leaks inside the purification/drying building, a small leak and a pipeline rupture (initial flow rates 0.000138 kg/s and 0.0312 kg/s), under 150 ACH mechanical ventilation as well. The remaining ten scenarios were releases in open/semi-confined environment. Four scenarios concerned the storage cabinet, a small leak and a pipeline rupture (initial flow rates 0.0118 kg/s and 1.18 kg/s), under two ambient wind speed conditions (1.5 and 5 m/s). Four scenarios concerned the storage bank, a leak from one cylinder and a leak fed from the storage bank (0.0472 kg/s initial flow rates in both cases), at two wind speed conditions as above. Finally, the last two scenarios concern a large leak (0.0472 kg/s initial flow rate) from the refueling hose of one dispenser, at two wind speed conditions, as above. This paper presents the CFD methodology applied and discusses the results obtained from the performed calculations.