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This paper presents a QRA study on a gaseous hydrogen refueling station of 2010 World Expo. Risks to station personnel, to refueling customers and to third parties are evaluated respectively. Uncertainties that intervene in the risk analysis are also discussed. The results show that the leaks from compressors and dispensers are the main risk contributors to first party and second party risks of the Expo station, indicating that risk mitigation measures should in the first place be implemented on compressors and dispensers. For the sake of the safety of station personnel, customers, and people outside the Expo station, additional safety barrier systems must be implemented on compressors and dispensers to prevent continuous release of hydrogen from happening. With appropriate mitigation measures on compressors and dispensers, risks to all three parties of the Expo station can be reduced to the value lower than the risk acceptance criteria.

The potential risk exposure of people for hydrogen refueling stations is often a critical factor to gain authority approval and public acceptance. Quantitative risk assessment (QRA) is often used to quantify the risk around hydrogen facilities and support the communication with authorities during the permitting process. This paper shows a case study on a gaseous hydrogen refueling station using QRA methodology. Risks to station personnel, to refueling customers and to third parties are evaluated respectively. Both individual risk measure and societal risk measure are used in risk assessment. Results show that the compressor leak is the main contributor to risks of all three parties. Elevating compressors can be considered as an effective mitigation measure to reduce occupational risks while setting enclosure around compressors cannot. Both measures are effective to reduce risks to customers. As for third parties, societal risks can be reduced to ALARP region by either elevating compressors or setting enclosure around compressors. External safety distance of compressors cannot be considerably reduced by elevation of compressors, but can significantly be reduced by setting compressor enclosure. However, safety distances of the station are not very sensitive to both mitigation measures.

With the development of large-scale fell cell vehicle demonstration project worldwide, the global number of hydrogen refueling stations has increased rapidly in recent years. The external safety of hydrogen refueling stations has always been a public concern for its further development. This paper examines the harm effect distances of severe accidents for a gaseous hydrogen refueling station. First, different accident scenarios are assumed and their subsequent consequences are calculated, including physical explosion, jet fire, flash fire and confined vapor cloud explosion. Results show that physical explosion and worst case of confined vapor cloud explosion produce the longest harm effect distances for instantaneous release and continuous release, respectively. This indicates that they may be used as decisive consequences to the determination of safe distances. Second, the influences of different factors on harm effect distances are investigated, including those of release inventory, release pressure, release height, release angle, release diameter and wind velocity. Then, based on these results, several potential hazard mitigation measures are proposed such as elevating hydrogen equipment, using smaller vessel and adopting smaller pipe work, if reasonably practicable.

Inadequation of the hydrogen refueling station is one of the primary factors that impede the commercialization of fuel cell vehicles (FCVs). Fast filling of high pressure hydrogen for FCVs is the key issue of refueling operation. During the hydrogen filling process, the temperature rise in the hydrogen tank makes it difficult to provide a safe, fast and accurate fill and the operating conditions should be controlled. In this paper, the research results on temperature behavior of the hydrogen tank and the filling procedure are summarized, and the further research areas on hydrogen refueling are also discussed.