Double-shelled inertial confinement fusion targets in which the outer shell is exploded have been studied with LASNEX. To achieve high DT density, configurations have been found in which the inner shell is ablatively driven by the hot outer shell. Calculations indicate that greater than 100 times liquid DT density can be achieved with the Shiva laser while still retaining some of the symmetry and stability advantages of the single-shelled exploding pusher target. The relative merits of transferring energy to the inner shell by electron conduction and by hydrodynamic work will be discussed.

The handling and disposal of brine effluents is a critical part of any geothermal conversion process. Brine effluents from the San Diego Gas and Electric/Department of Energy--Geothermal Loop Experimental Facility were characterized for particulate concentration and chemical composition. Bench scale tests were conducted with inorganic and organic coagulants as a means of enhancing the sedimentation process for separation and removal of suspended solids, principally amorphous silica. The effects of temperature, retention time, and pH on the precipitation of supersaturated silica, subsequent floc settling properties, and supernatant clarity were also determined. A design of a pilot scale clarifier now undergoing testing is also described.

This report is concerned with improving estimates for the residence times of atmospheric trace constituents in various atmospheric reservoirs. Residence times are defined only for steady-state conditions; i.e., when the net growth rate vanishes. The most useful case of vanishing net growth rate is when the total growth rate is equal to the decay rate. It is demonstrated that the most important advance towards improving estimates of pollutant residence times is through proper choices of reservoirs. Chosen reservoirs should possess the following features: steady-state conditions, uniform mixing ratio throughout or throughout specified subreservoirs, and subreservoirs chosen in which removal rates can be treated as approximate constants. An example of a poorly mixed reservoir, the stratosphere, is discussed. In another example, it is suggested that commonly used reservoirs for atmospheric CO/sub 2/ have been chosen poorly and that a substantial portion of the anthropogenic CO/sub 2/ released during the past 50 years may still be mixing into the stratosphere. In another example, it is suggested that determination of the dry deposition velocity for accumulation-mode aerosol particles may not be so important as previously thought. To improve estimates for the atmospheric residence times of these particles, it is important to increase knowledge …

Some primary material, macrostructural and tectonic features of typical geological formations are identified, insofar as they affect the hydraulic fracturing operation whereby suitably treated fluid is pumped into massive crack(s) underground: the retardation or channeling due to strata interfaces, discontinuities and other heterogeneities is roughly characterized, in the context of fully three-dimensional crack shape evolution, and the initiation from oriented boreholes is discussed in detail. A general-purpose numerical scheme is described, efficiently based on a physically transparent distribution of discontinuity multipoles (or dislocations) and the solution of resulting singular integral equations, which permits precise quantification of these effects: in particular, the barriers provided by adjacent stiffer and tougher strata are properly rationalized and the roles of inelastic slippage, blunting, branching, arrest, and re-initiation are placed in more transparent perspective. Stabilization effects due to alterations of pore-fluid pressure (and hence effective decohering stress), or the flux of formation fluid into the open region near to the crack tip, are described as potentially unfavorable for hydrofrac containment. However, the dominant time-dependent mechanism of frac fluid penetration into the narrow crack aperture attracts most attention: this process is very naturally and tractably incorporated in our comprehensive numerical formulation so that realistic simulation of …

Two methods for measuring the leach rates of simulated high level waste glass are compared. One is a modification of the standard IAEA method and the other is a one-pass method in which fresh leachant solution is pumped over the sample at a controlled flow rate and temperature. For times up to 3 days, there is close agreement between results from the two methods at 25.0C. Leach rates from the one-pass method show no correlation with flow rate at 25.0C, but at 75.0C leach rate increases with flow rate. Np-237 rates at 75.0C are greater than those at 25.0C, but /sup 239/Pu rates at 75.0C are less than or equal to those at 25.0C. Resorption of /sup 239/Pu associated with (SiO/sub 2/)/sub x/ polymers at high temperature is suggested as a possible cause.

The time-dependent Hartree-Fock method is used to produce time dependent graphical representations of the density contours of the binary cluster in the reactions /sup 14/N(112 MeV) + /sup 12/C, /sup 16/O(384 MeV) + /sup 16/O, and /sup 20/Ne(164 MeV) + /sup 58/Ni. Alpha clustering and multipole shape vibrations are seen. Predictions for d sigma/d..cap omega.., d sigma/dZ/sub f/, and d/sup 2/sigma(E/sub f/)d..cap omega..dE/sub f/vertical/sub z//sub f/ are obtained in the case of /sup 14/N + /sup 12/C and found to agree well with available experimental data. It is concluded that cluster dynamics play an essential role in heavy-ion reactions.

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Stress corrosion of carbon steel storage tanks containing alkaline nitrate radioactive waste, at the Savannah River Plant is controlled by specification of limits on waste composition and temperature. Actual cases of cracking have occurred in the primary steel shell of tanks designed and built before 1960 and were attributed to a combination of high residual stresses from fabrication welding and aggressiveness of fresh wastes from the reactor fuel reprocessing plants. The fresh wastes have the highest concentration of nitrate, which has been shown to be the cracking agent. Also as the waste solutions age and are reduced in volume by evaporation of water, nitrite and hydroxide ions become more concentrated and inhibit stress corrosion. Thus, by providing a heel of aged evaporated waste in tanks that receive fresh waste, concentrations of the inhibitor ions are maintained within specified ranges to protect against nitrate cracking. Tanks designed and built since 1960 have been made of steels with greater resistance to stress corrosion; these tanks have also been heat treated after fabrication to relieve residual stresses from construction operations. Temperature limits are also specified to protect against stress corrosion at elevated temperatures.