Fabrication of Inertial Confinement Fusion (ICF) targets requires deposition of various types of coatings on microspheres. The mechanical strength, and surface finish of the coatings are of concern in ICF experiments. The tensile strength of coatings can be controlled through grain refinement, selective doping and alloy formation. We have constructed a magnetron co-sputtering system to produce variable density profile coatings with high tensile strength on microspheres. The preliminary data on the properties of a Au-Cu binary alloy system by SEM and STEM analysis is presented.

A study was conducted to determine the effect of phantom size, shape and composition on the response of an albedo neutron dosimeter. The most important feature was the shape. The dose equivalent rate from a californium neutron source was determined. Ten different dose rates were determined which varied from 2.39 to 3.02 rem/h for the CF source used. (ACR)

A conceptual design study of a large 12-T yin-yang pair of coils, typical of the plug coils envisioned for a tandem-mirror facility to follow MFTF, has been completed. Because of its larger size and field strength, the magnetic forces are much greater than those experienced on MFTF. The main purpose of this study, therefore, is to assess the feasibility of such a device, paying particular attention to mechanical stress and conductor strain. The conductor proposed operates at 15.6 kA and consists of a rectangular half-hard copper stabilizer with a Nb-Ti insert in the low-field regions and Nb/sub 3/Sn in the high field. The coil is divided into four sections in the longitudinal direction, with steel substructure to limit the winding stress to an acceptable level. The conductor is cryostatically stabilized in superfluid He at 1.8K and 1.2 atm, with an operating heat flux of 0.8 W.cm/sup -2/.

Core snubbers, located near the neutral beam source ends of the Mirror Fusion Test Facility (MFTF) Sustaining Neutral Beam Power Supply System (SNBPSS) source cables, protect the neutral beam source extractor grid wires from overheating and sputtering during internal sparkdowns. The snubbers work by producing an induced counter-emf which limits the fault current and by absorbing the capacitive energy stored on the 80 kV source cables and power supplies. A computer program STACAL was used in snubber magnetic design to choose appropriate tape wound cores to provide 400 ..cap omega.. resistance and 25 J energy absorption. The cores are mounted horizontally in a dielectric structure. The central source cable bundle passes through the snubber and terminates on three copper buses. Multilam receptacles on the buses connect to the source module jumper cables. Corona rings and shields limit electric field stresses to allow close clearances between snubbers. A filament circuit shunt bias winding wound on a dielectric cylinder surrounds the cores. The dc voltage holdoff of a single snubber has been tested. Current and voltage behavior during capacitor bank and source cable discharges are presented.

Heat is radiated from both the vacuum vessel that houses the magnet and the heated plasma that exists at the central region of the magnets. Approximately 30 kW of heat will be transmitted to the 311 m/sup 2/ of magnet surface area from these two heat sources. We can reduce this heat load substantially by installing liquid nitrogen (LN)-filled panels around the magnets to counteract the 300/sup 0/K vessel wall temperature. When flowing the LN inside the panels, the temperature drops to 85/sup 0/K. These LN panels also serve as thermal protection for the helium pipings in the MFTF magnet system. However, near the plasma where a higher heat load is generated, we must add water panels to protect the LN panels. All the LN panels, water panels, and their manifoldings are called the magnet liners. Of the total of 344 pieces, 240 are used directly on the magnets. The support system that mounts these LN liner panels on the magnets is the topic of this paper.

The conductor development and the magnet design and construction for the MFTF are described. Future plans for the Mirror Program and their influence on the associated superconductor development program are discussed. Included is a summary of the progress being made to develop large, high-field, multifilamentary Nb/sub 3/Sn superconductors and the feasibility of building a 12-T yin-yang set of coils for the machine to follow MFTF. In a further look into the future, possible magnetic configurations and requirements for mirror reactors are surveyed.

Fabrication of Inertial Confinement Fusion (ICF) targets requires deposition of various types of coatings on microspheres. The mechanical strength, and surface finish of the coatings are of concern in ICF experiments. The tensile strength of coatings can be controlled through grain refinement, selective doping and alloy formation. We have constructed a magnetron co-sputtering system to produce variable density profile coatings with high tensile strength on microspheres.

The development of hydrothermal energy for direct heat applications is being accelerated by twenty-two demonstration projects that are funded on a cost-sharing basis by the US Department of Energy, Division of Geothermal Energy. These projects are designed to demonstrate the technical and economic feasibility of the direct use of hydrothermal resources in the United States. Engineering and economic data for the projects are summarized. The data and experience being generated by these projects will serve as an important basis for future direct heat development.

In our quest to understand radiation damage in materials, it is vital that we characterize radiation sources in terms of neutron flux and spectra as well as the more-fundamental displacement damage, gas production, and transmutation rates. Such data are crucial to correlations of materials-property changes in different environments and to predictions of materials performance in inaccessible environments, such as fusion reactors. Dosimetry techniques have been developed to measure the neutron flux and spectra in diverse facilities including thermal, fast, and mixed reactors, T (d,n) and Be (d,n) accelerator sources, and high-energy spallation sources. Displacement-damage cross sections have been calculated for 36 elements spanning the periodic table. All of these exposure parameters can now be routinely measured with 10 to 15% relative accuracy at all existing radiation-effect facilities. 4 tables.

The Advanced Test Accelerator (ATA) is a pulsed linear induction accelerator with the following design parameters: 50 MeV, 10 kA, 70 ns, and 1 kHz in a ten-pulse burst. Acceleration is accomplished by means of 190 ferrite-loaded cells, each capable of maintaining a 250 kV voltage pulse for 70 ns across a 1-inch gap. The unique characteristic of this machine is its 1 kHz burst mode capability at very high currents. This paper dscribes the pulse power development program which used the Experimental Test Accelerator (ETA) technology as a starting base. Considerable changes have been made both electrically and mechanically in the pulse power components with special consideration being given to the design to achieve higher reliability. A prototype module which incorporates all the pulse power components has been built and tested for millions of shots. Prototype components and test results are described.

An alloy of type 316 stainless steel with the addition of 0.23% Ti (316 + Ti) has been irradiated in the 20% cold-worked condition in the HFIR (a mixed fast and thermal neutron spectrum reactor) and tested near the irradiation temperature in the range of 300 to 600/sup 0/C. Tensile tests were performed following irradiation to fluence levels of 0.63 to 2.1 x 10/sup 26/ n/m/sup 2/ (E > 0.1 MeV) and helium levels of 200 to 1000 at. ppM. The 316 + Ti exhibited higher strength and lower ductility than similarly irradiated type 316 stainless steel (316 SS). However, the tensile elongation of 316 + Ti tends to saturate with increasing fluence at 575/sup 0/C whereas the elongation of 316 SS continues to fall for the fluences investigated. Reduction of area is similar for the two alloys, and 316 + Ti shows completely ductile rupture at 450/sup 0/C and below. The differences in strength and ductility are attributed to the influence of TiC precipitates trapping helium in the matrix.