Grain boundary precipitation was observed in a multipass GTA weld in 21-6-9 stainless steel. The precipitate was identified bby electron diffraction as Msub23 Csub6-type carbide. The presence of these carbide particles did not cause intergranular attack in standard corrosion tests.

Value Engineering, simply defined, is a systematic approach to getting more for your money. It has been used to reduce the cost of a wide variety of products by the D.O.D. and in principle, should be applicable to various phases of the Neutral Beam Program. With respect to R and D, the principles of Value Engineering must be used with caution. They are most effective in evaluating directed development with very specific goals, but can be misleading when considering advanced innovative work.

Published Hugoniot data for UO/sub 2/ is in error, because the measuring techniques used did not resolve the strong multiple-wave shock-structures present. Hence calculations related to liquid metal, fast-breeder-reactor, excursion analyses based on extrapolations of that data are in serious error. The inclined prism, flash gap, and two-stage gas-gun techniques are used to determine shock-compression parameters for UO/sub 2/ to 300 GPa. The Hugoniot elastic limit for UO/sub 2/ was found to be 5.7 GPa. At higher pressure, a plot of shock vs particle velocity displays a discontinuity between 1.0 < U/sub p/ < 1.8 km/s, which appears to be a manifestation of a solid-solid phase transition. For 1.8 < U/sub p/ < 4.0 km/s, the plot is given by U/sub s/ = 5.8 + 1.28 (U/sub p/ - 1.8).

The transfer of energy produced by the interaction of the intense pulses of short-ranged fusion microexplosion products with materials is one of the most difficult problems in inertially-confined fusion (ICF) reactor design. The short time and deposition distance for the energy results in local peak power densities on the order of 10/sup 18/ watts/m/sup 3/. High local power densities may cause change of state or spall in the reactor materials. This will limit the structure lifetimes for ICF reactors of economic physical sizes, increasing operating costs including structure replacement and radioactive waste management. Four basic first wall protection methods have evolved: a dry-wall, a wet-wall, a magnetically shielded wall, and a fluid wall. These approaches are distinguished by the way the reactor wall interfaces with fusion debris as well as the way the ambient cavity conditions modify the fusion energy forms and spectra at the first wall. Each of these approaches requires different heat transfer considerations.

During the past year we studied in detail plasma-first wall material damage induced by unipolar arcing. Unipolar arcing damage was analyzed as a function of material, surface preparation and microstructure. Unipolar arcing was found on all materials tested and the percentage of the surface area affected by arcing was similar for different metals. The severity of unipolar arcing was found to be very sensitive to microstructure. This was deduced through extensive study of different heat treatments of Ti-6Al,4V.

A full description is given of a glow discharge deposition system, as well as a schematic. A growth rate of 2 to 3 A/sec is reported across a total substrate diameter of 76 mm, and films of a-Si:H free of oxygen and carbon contaminants have been obtained. Other films deposited include: doped and undoped a-Si:H and a-Si/sub x/C/sub 1-x/:H, n-i-p, a-Si:H plus n-i-p, a-Si:H plus a-Si/xub x/C/sub 1-x/. Optical transmission measurements from .35 to 50 microns wavelength were made on these films. A significant difference found in the vibrational spectra is the shift of the major stretching mode from 2000 cm/sup -1/ for a-Si:H to 2100 cm/sup -1/ for the a-SiC:H. A strong broad band centered at 1000 cm/sup -1/ appears when carbon is present. (LEW)