Publications

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Legacy plutonium-bearing materials are stored in shipping containers at the Savannah River Site (SRS) until their final disposition can be determined. This material has been stabilized and is maintained per the DOE’s standard for long-term storage of Pu-containing materials, DOE-STD-3013. As a part of its ongoing storage mission, Washington Savannah River Company’s (WSRC) Nuclear Materials Management (NMM) organization is tasked with a surveillance program that will ensure these materials have remained in their expected condition over the several years of storage. Information from this program will be used by multiple entities to further validate the safe storage of Pu-bearing materials per DOE-STD-3013. Part of the program entails cutting open selected 3013 containers and sampling the materials inside. These samples will then be analyzed by Savannah River National Laboratory (SRNL). The remaining material not used for samples will then be repackaged in non-3013 containers to be placed back into shipping packages for storage until disposition at SRS. These repackaged materials will be stored per the requirements of DOE’s Criteria for Interim Safe Storage of Plutonium Bearing Materials (ISSC).

Hydrogen getters were tested for use in storage of plutonium-bearing materials in accordance with DOE's Criteria for Interim Safe Storage of Plutonium Bearing Materials. The hydrogen getter HITOP was aged for 3 months at 70 C and tested under both recombination and hydrogenation conditions at 20 and 70 C; partially saturated and irradiated aged getter samples were also tested. The recombination reaction was found to be very fast and well above the required rate of 45 std. cc H2h. The gettering reaction, which is planned as the backup reaction in this deployment, is slower and may not meet the requirements alone. Pressure drop measurements and {sup 1}H NMR analyses support these conclusions. Although the experimental conditions do not exactly replicate the deployment conditions, the results of our conservative experiments are clear: the aged getter shows sufficient reactivity to maintain hydrogen concentrations below the flammability limit, between the minimum and maximum deployment temperatures, for three months. The flammability risk is further reduced by the removal of oxygen through the recombination reaction. Neither radiation exposure nor thermal aging sufficiently degrades the getter to be a concern. Future testing to evaluate performance for longer aging periods is in progress.