Large variations in pressure from external gas-fueling sources and from plasma-induced wall reflux along the TMX-U plasma have been observed. These pressure variations can produce locally high neutral density in the plasma, which strongly affects the plasma parameters. These local pressure measurements include data from a newly installed neutral-pressure diagnostic system of fast magnetron gauges. The plasma-induced warm-wall reflux has been observed to be primarily HD and H/sub 2/ as opposed to D/sub 2/. This observation supports the model that all of the neutral D/sub 2/ gas enters the plasma region, strikes the plasma first, and is dissociated. The part of the D/sub 2/ gas, which is not absorbed as ions, strikes a wall, where it is converted to HD. Electron induced wall desorption measured by a mass spectrograph and actual analysis of the Ti indicates predominately H/sub 2/ instead of D/sub 2/ wall loading in TMX-U.

Large variations in pressure from external gas-fueling sources and from plasma-induced wall reflux along the TMX-U plasma have been observed. These pressure variations can produce locally high neutral density in the plasma, which strongly affects the plasma parameters. These local pressure measurements include data from a newly installed neutral-pressure diagnostic system of fast magnetron gauges. The plasma-induced warm-wall reflux has been observed to be primarily HD and H/sub 2/ as opposed to D/sub 2/. This observation supports the model that all of the neutral D/sub 2/ gas enters the plasma region, strikes the plasma first, and is dissociated. The part of the D/sub 2/ gas, which is not absorbed as ions, strikes a wall, where it is converted to HD. Electron induced wall desorption measured by a mass spectroscopy and actual analysis of the Ti indicates predominately H/sub 2/ instead of D/sub 2/ wall loading in TMX-U.

The Seismic Safety Margins Research Program (SSMRP) was a program conducted to develop a complete, fully coupled analysis procedure (including methods and computer codes) for estimating the risk of an earthquake induced radioactive release from a commercial nuclear power plant. The analysis procedure was based on a state-of-the-art evaluation of then current seismic analysis and design processes, and it explicitly attempted to account for some of the uncertainties inherent in such processes. This report identifies some of the files used in the analysis.

Single-crystal forms of MgAl/sub 2/O/sub 4/, Y/sub 3//Al/sub 5/O/sub 12/, and Al/sub 2/O/sub 3/ were irradiated in the EBR-II fast fission reactor to a fluence of 0.3 x 10/sup 26/ n/m/sup 2/ at 1015/sup 0/K, and to /sup -/1 to 2 x 10/sup 26/ n/m/sup 2/ at 925 and 1100/sup 0/K. Fracture toughness was subsequently measured at room temperature by an indentation technique, and radiation-induced defect aggregates were characterized by transmission electron microscopy. A slight increase in toughness of MgAl/sub 2/O/sub 4/ was observed, and attributed to interaction of cracks with strain fields around dislocation loops. No significant change was noted for Y/sub 3/Al/sub 5/O/sub 12/, despite the presence of a high concentration of unresolved defect clusters. Fracture toughness of Al/sub 2/O/sub 3/ was markedly increased, with the enhancement apparently attributable in large part to impedance of crack propagation by interaction with the irradiation-induced void lattice.

Thermodynamic calculations have been made to compare the thermochemical performance of the fusion reactor breeder blanket materials, Li/sub 2/O, LiAlO/sub 2/, and Li/sub 4/SiO/sub 4/ in the temperature range 900 to 1300K and in the oxygen activity range 10/sup -25/ to 10/sup -5/. In general, LiAlO/sub 2/ offers advantages over Li/sub 2/O, and Li/sub 2/O in turn appears better than Li/sub 4/SiO/sub 4/. The protium purge technique of enhancing tritium release is explored for the LiAlO/sub 2/ system. Oxygen activity is an influential variable in these systems and must be considered in executing and interpreting measurements on rates of tritium release, the chemical form of the released tritium, diffusion of tritiated species and their identities, retention of tritium in the condensed phase, and solubility of hydrogen isotope gases. Surface adsorption is seen as a potentially significant contributor to tritium inventory.

This paper discusses biological effects associated with overexposure to ultrasound, exposure standards proposed for airborne and contact ultrasound, industrial hygiene controls that can be employed to minimize exposure, and the instrumentation that is required for evaluating exposures.

The tandem high-density hydrogen negative-ion-source system is optimized to identify the largest possible ion concentrations and extracted ion currents. The optimization includes varying the length of the second chamber, varying neutral gas and electron densities, and varying the ratio of atomic to molecular density. Vibrational excitation occurs via high-energy electron excitation (E-V process) and H/sub 2//sup +/ surface neutralization (s-V process). These processes are considered separately and acting in parallel. The solutions are presented in terms of a dimensional scale factor, R. For a system scale length R = 1 cm, optimum extracted current densities are in the range 50 to 100 mA cm/sup -2/. A single-chamber s-V system with the high-energy electron component suppressed can provide larger ion concentrations than a tandem E-V, s-V system. 14 references, 10 figures.