The primary purpose of a bell jar is to collect and measure out gassing from a container (e.g., food can) of plutonium bearing materials to evaluate potential pressurization within a shipping package containment vessel. The bell jar allows for testing of the actual cans to be shipped without repackaging or taking samples of the materials. Pressurization of the bell jar can be readily extrapolated to the conditions inside the shipping container containment vessel during a shipment. Bell jar testing is being used in conjunction with current plutonium surveillance techniques (lid deflection measuring) to demonstrate that the cans bearing plutonium material may be shipped safely across the Savannah River Site for processing. Statistical sampling of similar materials leverages the testing such that only population subsets need be tested. The pressurization (or depressurization) measured in the bell jar to date has been very small and of no concern from a shipping perspective.
Gas Generation Test Support for Transportation and Storage of Plutonium Residue Materials - Part 1: Rocky Flats Sand, Slag, and Crucible Residues