Pressure Development in Sealed Containers with Plutonium-bearing Materials

摘要

Gas generation by plutonium-bearing materials in sealed containers has been studied. The gas composition and pressure are determined over periods from months to years. The Pu bearing materials studied represent those produced by all of the major processes used by the U.S. Department of Energy (DOE) in the processing of plutonium and include the maximum amount of water (0.5 percent by weight) allowed by DOE's 3013 Standard. Hydrogen generation is of high interest and the Pu bearing materials can be classed according to how much hydrogen is generated. Hydrogen generation by high purity plutonium oxides packaged under conditions typical for actual 3013 materials is minimal, with very low generation rates and low equilibrium pressures. Materials with chloride salt impurities have much higher hydrogen gas generation rates and result in the highest observed equilibrium hydrogen pressures. Other materials such as those with high metal oxide impurities generate hydrogen at rates in between these extremes. The fraction of water that is converted to hydrogen gas as equilibrium is approached ranges from 0 percent to 25 percent under conditions typical of materials packaged to the 3013 Standard. Generation of both hydrogen and oxygen occurs when liquid water is present. The material and moisture conditions that result in hydrogen and oxygen generation for high-purity plutonium oxide and chloride salt-bearing plutonium oxide materials have been characterized. Other gases that are observed include nitrous oxide, carbon dioxide, carbon monoxide, and methane.