Reductions in the size of the U. S. nuclear weapons arsenal resulted in the need to store large quantities of plutonium-bearing metals and oxides for prolonged periods of time. To assure that the excess plutonium from the U. S. Department of Energy (DOE) sites was stored in a safe and environmentally friendly manner the plutonium-bearing materials are stabilized and packaged according to well developed criteria published as a DOE Standard. The packaged materials are stored in secure facilities and regular surveillance activities are conducted to assure continuing package integrity. The stabilization, packaging, storage and surveillance requirements were developed through extensive science and engineering activities including those related to: plutonium-environment interactions and container pressurization, corrosion and stress corrosion cracking, plutonium-container material interactions, loss of sealing capability and changes in heat transfer characteristics. This paper summarizes some of those activities and outlines ongoing science and engineering programs that assure continued safe and secure storage of the plutonium-bearing metals and oxides.

I discuss a number of novel phenomenological features of QCD in high transverse momentum reactions. The presence of direct higher-twist processes, where a proton is produced directly in the hard subprocess, can explain the 'baryon anomaly' - the large proton-to-pion ratio seen at RHIC in high centrality heavy ion collisions. Direct hadronic processes can also account for the deviation from leading-twist PQCD scaling at fixed x{sub T} = 2 p{sub T}/{radical}s. I suggest that the 'ridge' --the same-side long-range rapidity correlation observed at RHIC in high centrality heavy ion collisions is due to the imprint of semihard DGLAP gluon radiation from initial-state partons which have transverse momenta biased toward the trigger. A model for early thermalization of the quark-gluon medium is also outlined. Rescattering interactions from gluon-exchange, normally neglected in the parton model, have a profound effect in QCD hard-scattering reactions, leading to leading-twist single-spin asymmetries, diffractive deep inelastic scattering, diffractive hard hadronic reactions, the breakdown of the Lam-Tung relation in Drell-Yan reactions, nuclear shadowing--all leading-twist dynamics not incorporated in the light-front wavefunctions of the target computed in isolation. Anti shadowing is shown to be quark flavor specific and thus different in charged and neutral deep inelastic lepton-nucleus scattering. I …

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The competition between the addition of polar, oxygen-containing functional groups (functionalization) and the cleavage of C-C bonds (fragmentation) has a governing influence on the change in volatility of organic species upon atmospheric oxidation, and hence on the loading of tropospheric organic aerosol. However the branching between these two channels is generally poorly constrained for oxidized organics. Here we determine functionalization/fragmentation branching ratios for organics spanning a range of oxidation levels, using the heterogeneous oxidation of squalane (C30H62) as a model system. Squalane particles are exposed to high concentrations of OH in a flow reactor, and measurements of particle mass and elemental ratios enable the determination of absolute elemental composition (number of oxygen, carbon, and hydrogen atoms) of the oxidized particles. At low OH exposures, the oxygen content of the organics increases, indicating that functionalization dominates, whereas at higher exposures the amount of carbon in the particles decreases, indicating the increasing importance of fragmentation processes. Once the organics are moderately oxidized (O/C~;;0.4), fragmentation completely dominates, and the increase in O/C ratio upon further oxidation is due to the loss of carbon rather than the addition of oxygen. These results suggest that fragmentation reactions may be key steps in the atmospheric formation …

The Savannah River National Laboratory (SRNL) initiated a sludge matrix study to evaluate the impact of changing insoluble solid composition on the processing characteristics of slurries in the Defense Waste Processing Facility (DWPF). Three compositional ranges were developed for three groups of elements in the waste. The first was high iron/low aluminum versus low iron/high aluminum. The second was high calcium-manganese/low nickel, chromium, and magnesium versus low calcium-manganese/high nickel, chromium, and magnesium. The third was high noble metals (Ag, Pd, Rh, Ru) versus low noble metals. These three options can be combined to form eight distinct sludge compositions. The sludge matrix study called for testing each of these eight simulants near the minimum acid required for nitrite destruction and at a second acid level that produced significant hydrogen by noble metal catalyzed decomposition of formic acid. Four simulants were prepared based on the four possible combinations of the Al/Fe and Mn-Ca/Mg-Ni-Cr options. Preliminary simulant preparation work has already been documented. The four simulants can be used for both high and low noble metal concentration testing and high and low acid testing. This report summarizes preliminary testing of each of the four simulants at low noble metals and low acid stoichiometry. …

Significant progress has been made in the past two years in improving the understanding of acid consumption and catalytic hydrogen generation during the Defense Waste Processing Facility (DWPF) processing of waste sludges in the Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME). This report reviews issues listed in prior internal reviews, describes progress with respect to the recommendations made by the December 2006 external review panel, and presents a summary of the current understanding of catalytic hydrogen generation in the DWPF Chemical Process Cell (CPC). Noble metals, such as Pd, Rh, and Ru, are historically known catalysts for the conversion of formic acid into hydrogen and carbon dioxide. Rh, Ru, and Pd are present in the DWPF SRAT feed as by-products of thermal neutron fission of {sup 235}U in the original waste. Rhodium appears to become most active for hydrogen as the nitrite ion concentration becomes low (within a factor of ten of the Rh concentration). Prior to hydrogen generation, Rh is definitely active for nitrite destruction to N{sub 2}O and potentially active for nitrite to NO formation. These reactions are all consistent with the presence of a nitro-Rh complex catalyst, although definite proof for the existence …