Probabilistische Zuverlässigkeits- und Risikountersuchung der Photovoltaik-Wasserstoff-Brennstoffzellen-Demonstrationsanlage PHOEBUS Jülich

The probabilistic reliability and risk analysis o£ the Photovoltaic-Hydrogen-Fuel Cell-Demonstration-Facility PHOEBUS Juelich, provides comprehensive information on the essential accidents in such plants. The result for PHOEBUS is a high safety level which, in principle, is based upon passively safe components (storage tanks, pipes) and highly reliable safety measures (gas supervision, leak disconnection, active venting system). The hazardous potential of the facility is given by inadvertant hydrogen release with possible explosions, where small releases are controled already by the natural venting. The study has shown that event sequences with hydrogen release from the high pressure storage tanks outside with subsequent explosion ofthe evolved hydrogen-air mixture dominate theenvironmentral risk which is low in total though. Major contributions are also provided by uncontroled hydrogen releases within the experimental hall and an emergency corridor. Operation errors are expected to be rare due to the high degree of automation ofthe plant and, even then, play an insignificant role. The consequences of processing errors are limited to the immediate area of the respective components. An extension is highly unlikely due to the protection measures.The study characterizes the accidents investigated by their frequency of occurence, by the amount of hydrogen released, and by the consequences of possible explosions, basically site damages with jeopardization of people. The individual risk arising by this facility is as low as 1,0 $\cdot$ 10$^{-5}$/a and is restricted to its immediate neighborhood (radius approx. 200 m). Severe earthquakes accompanied by a largerange destruction of most buildings are lying for the site Juelich with 1,0 $\cdot 10$^{-5}$/a in a comparable frequency range