The interactive effects of elevated temperatures and nutrient enrichment on periphyton communities on glass slides were studied for one year in the Flowing Streams Laboratory, operated by Savannah River Laboratory (SRL) for the Department of Energy (Figure 1). Water from a South Carolina stream called Upper Three Runs, characterized by low pH and low nutrient concentrations and with intermittent swamp drainage, was used.

Welds in austenitic stainless steel pipes are notoriously difficult to nondestructively examine using conventional ultrasonic and eddy current methods. Survace irregularities and microscopic variations in magnetic permeability cause false eddy current signal variations. Ultrasonic methods have been developed which use computer processing of the data to overcome some of the problems. Electro-thermal nondestructive testing shows promise for detecting flaws that are difficult to detect using other NDT methods. Results of a project completed to develop and demonstrate the potential of an electro-thermal method for nondestructively testing stainless steel pipe welds are presented. Electro-thermal NDT uses a brief pulse of electrical current injected into the pipe. Defects at any depth within the weld cause small differences in surface electrical current distribution. These cause short-lived transient temperature differences on the pipe's surface that are mapped using an infrared scanning camera. Localized microstructural differences and normal surface roughness in the welds have little effect on the surface temperatures.

A canonical resolution of the multiplicity problem was proven for U(3) and this resolution is extended to a determination of all U(n) tensor operators characterized by maximal null space. 9 references.

The relativistic multigroup diffusion equations describing superthermal electron transport in laser fusion plasmas were derived in an earlier UCRL. A successful numerical scheme based on these equations which is now being used to model laser fusion experiments is described.

Applications of seismic design criteria and qualification methods to the US breeder reactor projects have developed new findings, improvements in design methods, and identified areas for further development. Discussions are presented regarding site free field motion, soil-structure interaction, equipment response spectra, piping, snubbers and support design analyses, dynamic decoupling, seismic qualification testing, and protection of Seismic Category I components from Non-Category I equipment failures.

Four different models of the migration process have been reviewed to determine their suitability as a working model. While there are several common factors in the models additional factors are included to account for several possible effects. The detail of each model leads to a certain degree of difficulty in applying the model to the problem at hand. One model predicts that inclusions smaller than 0.1 mm dimension probably will not migrate. The other models do not consider size as a factor. Thermal diffusion (Soret effect) is considered insignificant in three models, while in the fourth model it is added to the concentration diffusion term. The following conclusions are made: (1) Temperature is the most significant parameter in all models and must be known as a function of time, and distance from the canister. (2) All four models predict about the same migration velocity for a given set of conditions. For 100/sup 0/C and 1/sup 0/C/cm thermal gradient, the individual values are 3.0, 4.8, 5.6 and 6.4 mm/y. (3) The diffusion of ions through the brine inclusions is the rate controlling mechanism. (4) The difference between the thermal gradients in the liquid and in the solid should always be considered, …

When canisters containing radwastes are emplaced in a repository the heat produced by the decaying radwaste will cause moderate thermal gradients to develop which will cause the brine present in a halite medium (salt deposits) to accumulate around the canister. Four different models of the migration process have been reviewed to determine their suitability as a working model. One model predicts that inclusions smaller than 0.1 mm dimension probably will not migrate. The other models do not consider size as a factor. Thermal diffusion (Soret effect) is considered insignificant in three models, while in the fourth model it is added to the concentration diffusion term. The following conclusions can be made: Temperature is the most significant parameter in all models and must be known as a function of time, and distance from the canister. All four models predict about the same migration velocity for it is a given set of conditions; for 100/sup 0/C and 1/sup 0/C/cm thermal gradient, it is 3.0, 4.8, 5.6 and 6.4 mm/y. Diffusion of ions through the brine inclusions is the rate controlling mechanism. The difference between the thermal gradients in the liquid and in the solid should always be considered and is a function …

A tabular lithium equation of state was formulated from three separate equation-of-state models to carry out hydrodynamic simulations of a lithium-waterfall laser-fusion reactor. The models we used are: ACTEX for the ionized fluid, soft-sphere for the liquid and vapor, and pseudopotential for the hot, dense liquid. The models are smoothly joined over the range of density and temperature conditions appropriate for a laser-fusion reactor. We also fitted the models into two forms suitable for hydrodynamic calculations.

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Recent theories in statistical mechanics and intermolecular forces are used to explain the shock-wave data of inert gases, diatomic molecules, and hydrocarbons.

Thick film coatings of beryllium, needed for the low-Z ablator layer in proposed laser fusion targets, have been prepared using high rate magnetron rf sputtering. The requirements for these Be coatings include thicknesses from 5 to 50 ..mu..m, complete freedom from surface defects, and an average surface roughness of 100 nm or less. We have sputtered very smooth, dense, thick Be films with surface roughness less than 100 nm. X-ray diffraction analysis of impurity doped films indicates an amorphous-like structure. Impurity stabilized amorphous Be with smooth surfaces is reported on both cooled copper and higher temperature glass substrates. The sputtering parameters (substrate temperature, deposition rate, argon pressure, and impurity gas levels) affecting surface roughness and film structure are discussed in terms of SEM, AES, and x-ray diffraction results.