Atomics International and Lawrence Livermore Laboratory are involved in the conceptual design of a laser fusion power plant incorporating the lithium fall target chamber. In this paper we discuss some of the more important design considerations for the target chamber and evaluate its nuclear performance. Sizing and configuration of the fall, hydraulic effects, and mechanical design considerations are addressed. The nuclear aspects examined include tritium breeding, energy deposition, and radiation damage.

One of the most difficult technology problems in an inertially confined fusion reactor is the survival of the structure from the repeated stresses caused by the microexplosion products. To mitigate the damage from the microexplosion products, a thick lithium fall can be circulated in front of the structure. This fall will absorb the short-ranged products and moderate and attenuate the neutrons. This paper discusses the response of the fall to the microexplosion products, and estimates the resulting loading and stresses in the first structural wall.

Geothermal energy development research at the Lawrence Livermore Laboratory through 1976 has been aimed at solving the problems associated with the use of high-temperature, high-salinity brines found in the Salton Sea Geothermal Field for their practical conversion to electrical energy. Specifically, part of the program has been oriented toward solving the problems of scale and solids deposition and corrosion of system components that are exposed to the highly mineralized brines. Brine acidification was found to be a promising method for controlling scale and solids deposition. Titanium, zirconium, and chromium-molybdenum alloys were shown to be the best economical corrosion-resistant materials for use in various parts of a total-flow turbine system. Scale and solids control and materials tests for conversion systems based on brine flashing are currently being evaluated. Some initial results and test plans are discussed.

The particle beam parameters needed for inertial fusion can be achieved with conventional accelerator technology if heavy ion machines attain the level of performance of the most intense high energy proton machines. Many of the problems posed by this goal pertain to the low energy portions of the accelerator system. In particular, the implied particle current in the rf linac is 10/sup 3/--10/sup 4/ times the values achieved with existing heavy ion machines. Much of this discrepancy is simply attributable to the great differences between the design considerations relevant to accelerators for fusion and those which have determined the performance of the existing machines. The basic concept chosen at Argonne National Laboratory is cavities containing single drift tubes mounted on lambda/4 supports. Such structures pose the least problem for the beam transport system, and one cavity is placed between adjacent quadrupole magnets. The average voltage gain of the first cells of the low velocity section is moderate; and, although probably acceptable and improved by the end of the 10 MV section, the low initial gain adds to the motivation provided by the transport problem to increase the preinjector voltage substantially above 750 kV.

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A typical braze joint consists of a metallic region which wets the surface of the two metals being joined, thereby achieving a bond of good mechanical integrity. An ultrasonic signal reflected from this bond can normally distinguish between bonded and unbonded regions but gives little information about the strength of such a region. For some brazes (and other bonding operations), there is a good correlation between thickness and bond strength in that a bond falling within a specified thickness range can be shown to perform adequately while both thinner and thicker bonds exhibit degraded performance. For a 50 ..mu..m thick braze, ultrasonic reflections are ''separated'' by roughly 16 nsec. For any real transducer, this means that there is significant overlap of the front and back surface reflections. We have studied a model system consisting of thin (12 to 90 ..mu..m) aluminum bonded to the back surface beryllium. By computer fitting the time dependence of the elastic disturbance reflected from the beryllium-aluminum region to a two-plane wave reflector model and allowing for multiple reflection, we correctly predict the interface separations. Details of the data acquisition and analysis, including the fitting procedure and an error analysis, are given. Accuracy depends upon the …