Hydrogen Diffusion through Multiple Packaging Layers

For this scenario, hydrogen is generated in a container that is eventually stored within a drum or some type of long range storage container. When preparing for long-term storage, the hydrogen container (HC) is placed in a plastic bag (PB1). The PB1 is then placed inside an inner drum (ID). The ID is placed inside a plastic bag (PB2) which is then placed within an outer drum (OD). One or more ODs are then storage is a large container (LC). Filtered vents or vent holes are located on all the container barriers to prevent pressurization and allow gases to flow in and out of the HC. The LC is vented to the atmosphere with four vent paths for this example. The source of hydrogen generation for this study is not important. Any source that generates hydrogen in elemental form (i.e., H{sub 2}) is a candidate for the purposes of this generic evaluation. The released hydrogen accumulates inside the waste packaging. Depending on the permeability of the packaging layers, some of the accumulated hydrogen may diffuse out of the packaging layers and into the space surrounding the drums. Since the drums are confined in the LC, the hydrogen accumulates in themore » LC as it did inside the drums if venting of the LC does not occur. If accumulation in the LC is allowed without venting, the confinement is eventually breached or the hydrogen is consumed by reaction with other chemical species. One possible reaction is combustion with oxygen. Such a reaction can be explosive, and from this possibility arises the safety concern.« less