**5.3. Occurrence frequency of accidents with explosive materials in stationary installations**

In that context, installations such as industrial plants, loading and discharging stations, storage tanks, gas pipelines have to be taken into account according to [3].

In case of natural gas the formation of an explosive gas mixture is only assumed for the accident area because the specific gravity of natural gas is less than the air and drifts of the gas mixture in the direction of the nuclear power plant are therefore excluded.
