In the last few years there has been significant progress in ICF research in laboratories in the United States and elsewhere. These advances have occurred in areas that range from demonstrating an innovative laser beam smoothing techniques important for both directly and indirectly driven ICF, to achieving a more complete understanding of capsule implosions and related physics. This progress has been possible because of the capabilities provided by the ICF laser-target facilities currently in operation and the new developments in diagnostics, particularly for measurements of the implosion process and the conditions in the compressed capsule core. Both of these topics, facilities and selected new diagnostics capabilities in the US ICF Program, are summarized in this paper. 32 refs., 19 figs., 6 tabs.

Sensitive radio-frequency (rf) amplifiers based on dc Superconducting QUantum Interface Devices (SQUIDS) are available for frequencies up to 200 MHz. At 4.2 K, the gain and noise temperature of a typical tuned amplifier are 18.6 +- 0.5 dB and 1.7 +- 0.5 K at 93 MHz. These amplifiers are being applied to a series of novel experiments on nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR). The high sensitivity of these amplifiers was demonstrated in the observation of ''nuclear spin noise'', the emission of photons by /sup 35/Cl nuclei in a state of zero polarization. In the more conventional experiments in which one applies a large rf pulse to the spins, a Q-spoiler, consisting of a series array of Josephson junctions, is used to reduce the Q of the input circuit to a very low value during the pulse. The Q-spoiler enables the circuit to recover quickly after the pulse, and has been used in an NQR experiment to achieve a sensitivity of about 2 /times/ 10/sup 16/ nuclear Bohr magnetons in a single free precession signal with a bandwidth of 10 kHz. In a third experiment, a sample containing /sup 35/Cl nuclei was placed in a capacitor and …

In most geothermal reservoirs large-scale permeability is dominated by fractures, while most of the heat and fluid reserves are stored in the rock matrix. Early-time fluid production comes mostly from the readily accessible fracture volume, while reservoir behavior at later time depends upon the ease with which fluid and heat can be transferred from the rock matrix to the fractures. Methods for modeling flow in fractured porous media must be able to deal with this matrix-fracture exchange, the so-called interporosity flow. This paper reviews recent work at Lawrence Berkeley Laboratory on numerical modeling of nonisothermal multiphase flow in fractured porous media. We also give a brief summary of simulation applications to problems in geothermal production and reinjection. 29 refs., 1 fig.

Analyses have been made for different structural alloys proposed for the International Thermonuclear Experimental Reactor (ITER). Candidate alloys include austenitic steels stabilized with nickel (NiSS) or manganese (MnSS). The radioactivity, the decay heat, and the waste disposal rating of each alloy have been calculated for the inboard shield of the ITER design option utilizing water cooled solid breeder blanket. The results show, for the 55 cm inboard shield and after 3 MW.yr/m2 fluence, that the long term activation problems, e.g., radioactive waste, of the MnSS are much less than that of the NiSS. All the MnSS alloys considered are qualified as Class C or better low level waste. Most of the NiSS alloys are not qualified for near surface burial. However, the short term decay heat generation rate for the MnSS is much higher than that of the NiSS. 6 refs., 8 figs., 2 tabs.

We have used the full Tucker theory including the quantum susceptance to fit data from planar lithographed mm-wave mixers with bow tie antennas and integrated RF coupling elements. Essentially perfect fits to pumped IV curves have been obtained. The deduced imbedding admittances agree well with those independently calculated from the geometry of the antenna and matching structures. We find that the quantum susceptance is essential to the fit and thus to predictions of the mixer performance. For junctions with moderately sharp gap structures, the quantum susceptance is especially important in the production of steps with low and/or negative dynamic conductance. 15 refs., 4 figs.

Emissions and atmospheric concentrations of several trace gases important to atmospheric chemistry are known to have increased substantially over recent decades. Solar flux variations and the atmospheric nuclear test series are also likely to have affected stratospheric ozone. In this study, the LLNL two-dimensional chemical-radiative-transport model of the troposphere and stratosphere has been applied to an analysis of the effects that these natural and anthropogenic influences may have had on global ozone concentrations over the last three decades. In general, model determined species distributions and the derived ozone trends agree well with published analyses of land-based and satellite-based observations. Also, the total ozone and ozone distribution trends derived from CFC and other trace gas effects have a different response with latitude than the derived trends from solar flux variations, thus providing a ''signature'' for anthropogenic effects on ozone. 24 refs., 5 figs.

Spectral processing in x-ray energy dispersive spectroscopy deals with the extraction of characteristic signals from experimental data. In this text, the four basic procedures for this methodology are reviewed and their limitations outlined. Quantification, on the other hand, deals with the interpretation of the information obtained from spectral processing. Here the limitations are for the most part instrumental in nature. The prospects of higher voltage operation does not, in theory, present any new problems and may in fact prove to be more desirable assuming that electron damage effects do not preclude analysis. 28 refs., 6 figs.

Targets using indirect drive optimize symmetry and are the mainline approach at LLNL based on a number of favorable factors. Recently we have also investigated several examples of ion beam targets that use the energy efficiency of direct drive while at the same time optimizing on the symmetry requirements. Heavy ion beams of charge state Z greater than or equal to 3 at 5-10 GeV have less than or equal to15-20 m bending radii with 3.5 Tesla fields. Beams like them could be used with targets involving direct drive. Control of asymmetries in direct-drive ion beam targets depends on control of the effects of residual target asymmetries after an appropriate illumination scheme has been adopted. In this article, we outline results on our investigations into ion beam target concepts in which the effects of residual asymmetries are ameliorated. Thirty-two beams are placed according to our axially symmetric Gaussian-quadrature illumination scheme. The targets survive the effects of residual asymmetries in our recent 2D hydrodynamic simulations. 7 refs., 5 figs.

After being informed that radioactive material from the Chernobyl nuclear power plant had been discovered on the clothing of workers at a Swedish reactor site, the United States Department of Energy requested that the Atmospheric Release Advisory Capability (ARAC) evaluate both the extent and the magnitude of the accident (Dickerson and Sullivan, 1987). ARAC is a real-time emergency response service that specializes in the regional assessment of radiological accidents using advanced dispersion models. While we possessed a sizable inventory of computer models with which to address this problem, we lacked an operational tool that could be used with confidence in determining the fate of airborne radioactivity beyond about 500 km. As an outgrowth of this experience, we began to explore the spatial limits of applicability of our Advection-Diffusion Particle-In-Cell (ADPIC) model (Lange, 1978). At the same time, we began testing a hybrid version of this model that uses the Air Force Global Weather Central's Northern Hemisphere Whole Mesh Grid of wind velocities as input. In combination, these models can provide, potentially, a response capability that extends from tens of kilometers to the entire Northern Hemisphere. 7 refs., 6 figs.

A water-cooled solid-breeder blanket concept was developed for ITER. The main function of this blanket is to produce the necessary tritium for the ITER operation. Several design features are incorporated in this blanket concept to increase its attractiveness. It is assumed that the blanket operation at commercial power reactor conditions can be sacrificed to achieve a high tritium breeding ratio with minimum additional research and development, and minimal impact on reactor design and operation. Operating temperature limits are enforced for each material to insure a satisfactory blanket performance. In fact, the design was iterated to maximize the tritium breeding ratio and satisfy these temperature limits. The other design constraint is to permit a large increase in the neutron wall loading without exceeding the temperature limits for the different blanket materials. The blanket concept contains 1.8 cm of Li/sub 2/O and 22.5 cm of beryllium both with a 0.8 density factor. The water coolant is isolated from the breeder material by several zones which reduces the tritium buildup in the water by permeation, reduces the chance for water-breeder interaction, and permits the breeder to operate at high temperature with a low temperature coolant. This improves the safety and environmental aspects of …

Experimental data for interdiffusion and phase equilibria in the U-Mo system have been obtained over the temperature range 1400 to 1525 K as a fallout from compatibility experiments in which UO/sub 2/ was decomposed by lithium in closed molybdenum capsules. Composition-position, x-ray diffraction and microstructural data from the interdiffusion zones indicate that the intermediate phase U/sub 2/Mo is found in this temperature range, contrary to the currently accepted equilibrium U-Mo phase diagram. The U-Mo interdiffusion data are in good agreement with published values. Inclusion of the U/sub 2/Mo phase in a theoretical correlation of interdiffusion and phase equilibria data using Darken's equation indicate that high temperature interdiffusion of uranium and molybdenum follows the usual thermodynamic rules. Significant changes in the value of the thermodynamic based Darken factor near the U/sub 2/Mo phase boundary on the high uranium side are indicated from both the new and published interdiffusion data. 9 refs., 10 figs., 3 tabs.

Fermilab's Advanced Computer Program (ACP) has been developing highly cost effective, yet practical, parallel computers for high energy physics since 1984. The ACP's latest developments are proceeding in two directions. A Second Generation ACP Multiprocessor System for experiments will include $3500 RISC processors each with performance over 15 VAX MIPS. To support such high performance, the new system allows parallel I/O, parallel interprocess communication, and parallel host processes. The ACP Multi-Array Processor, has been developed for theoretical physics. Each $4000 node is a FORTRAN or C programmable pipelined 20 MFlops (peak), 10 MByte single board computer. These are plugged into a 16 port crossbar switch crate which handles both inter and intra crate communication. The crates are connected in a hypercube. Site oriented applications like lattice gauge theory are supported by system software called CANOPY, which makes the hardware virtually transparent to users. A 256 node, 5 GFlop, system is under construction. 10 refs., 7 figs.

The Modular High-Temperature Gas-Cooled Reactor (MHTGR) is an advanced power plant concept which has been under design definition since 1984. The design utilizes basic high-temperature gas-cooled reactor features of ceramic fuel, helium coolant and a graphite moderator which have been under development for 30 years. The geometric arrangement of the reactor vessels, the core and the heat removal components has been selected to exploit the inherent characteristics associated with high temperature materials. The design utilizes passively safe features which provide a higher margin of safety and investment protection than current generation reactors. The design has been evaluated to be economically attractive relative to modern coal fired plants. The design and development program is a cooperative effort by the US government, the utilities and the nuclear industry. 8 refs., 4 figs., 4 tabs.

The performance of the ITER first wall and divertor plate is analyzed using a 1-D life-time code which includes the effects of radiation damage and surface erosion. The materials considered for the first wall are solution annealed and 20% cold-worked Type 316 stainless steel. The materials considered for the divertor plate are H-451 graphite bonded to a Cu-0.5 Be-2 Ni heat sink. The primary conclusion is that it is crucial to include radiation effects for obtaining realistic predictions of performance. 9 refs., 13 figs., 1 tab.

The 1970's and 1980's can be considered the third stage in the explosive development of condensed matter physics. After the very intensive research of the 1930's and 1940's, which followed the formulation of quantum mechanics, and the path-breaking activity of the 1950's and 1960's, the problems being faced now are much more complex and not always susceptible to simple modelling. The (subjectively) open problems discussed here are: high temperature superconductivity, its properties and the possible new mechanisms which lead to it; the integral and fractional quantum Hall effects; new forms of order in condensed-matter systems; the physics of disorder, especially the problem of spin glasses; the physics of complex anisotropic systems; the theoretical prediction of stable and metastable states of matter; the physics of highly correlated states (heavy fermions); the physics of artificially made structures, in particular heterostructures and highly metastable states of matter; the determination of the microscopic structure of surfaces; and chaos and highly nonlinear phnomena. 82 refs.

The fluence of high-energy muons that result from the operation of the Tevatron accelerator was measured downstream of the experimental area beam lines. Profiles were determined by use of plastic scintillators and associated electronics mounted in a mobile laboratory at various locations on-site and at the site boundary. The experimental method and the properties of the fluence profiles are summarized, and in one case the measurements are compared to Monte Carlo calculations of muon transport. 6 refs., 11 figs., 1 tab.

Superconducting Magnetic Energy Storage (SMES) plants have been proposed in both solenoidal and toroidal geometries. The former is efficient in terms of the quantity of superconductor required per unit of stored energy. For applications where a fringe field could be a problem, the toroidal geometry, which requires at least a factor of two more material, has been proposed. In addition to the solenoid and toroid, other geometries are possible, such as linear multipoles and spherical coils. These geometries have been considered for use in applications other than energy storage. In this report, the effectiveness (quantity of superconductor/stored energy) is calculated for various coil geometries. 7 refs., 4 tabs.

When pumping near the two-photon 3d resonance in pure sodium vapor and observing the backward hyper-Raman emission to the 3p substates, an asymmetry in ratios of 3p/sub 1/2/, 3p/sub 3/2/ associated emissions was observed dependent upon the direction of the initial laser detuning from the resonance. It has been determined that this asymmetry can be attributed to the ac Stark effect induced by the hyper-Raman emission itself. 3 refs., 3 figs.

Our demonstration of multiple-photon resonant cycling between the 1/sup 3/S and 2/sup 3/P states of ortho-Positronium (oPs) makes possible the production of cold positronium (Ps) through the technique of laser cooling. A simplified analysis of magnetic mixing in excited-state Ps is given. This effect is important both as a diagnostic of resonant cycling and Ps cooling. The significance of cold Ps in fine structure measurements and the formation of a Bose-Einstein condensate is discussed. 13 refs., 3 figs.

Radiative processes strongly effect equilibrium trace gas concentrations both directly, through photolysis reactions, and indirectly through temperature and transport processes. As part of our continuing radiative submodel development and validation, we have used the LLNL 2-D chemical-radiative-transport (CRT) model to investigate the net sensitivity of equilibrium ozone concentrations to several changes in radiative forcing. Doubling CO/sub 2/ from 300 ppmv to 600 ppmv resulted in a temperature decrease of 5 K to 8 K in the middle stratosphere along with an 8% to 16% increase in ozone in the same region. Replacing our usual shortwave scattering algorithms with a simplified Rayleigh algorithm led to a 1% to 2% increase in ozone in the lower stratosphere. Finally, modifying our normal CO/sub 2/ cooling rates by corrections derived from line-by-line calculations resulted in several regions of heating and cooling. We observed temperature changes on the order of 1 K to 1.5 K with corresponding changes of 0.5% to 1.5% in O/sub 3/. Our results for doubled CO/sub 2/ compare favorably with those by other authors. Results for our two perturbation scenarios stress the need for accurately modeling radiative processes while confirming the general validity of current 2-D CRT models. 15 refs., 5 …

The cost of structural components in a large superconducting coil may well exceed the coil and cryostat cost. As a result, the idea of constructing a system composed of two different coil types assembled in such a way that the sources balance and reduce the total structural requirement is oft proposed. A suitable geometry has never been found for the fundamental reason that there can be no force compensated solution. In this paper, the general problem is presented and an analysis of the energy stored and stresses produced in the structure are described in a fundamental way. Finally, the relation between structural mass M and stored energy E, M greater than or equal to/rho/E/sigma/sub w/, that is valid for all magnetic systems is developed, where /rho/ is the density of the structure and sigma/sub w/ is the working stress in the structure. 12 refs., 2 figs.

The CERN experiment WA80 studies ultrarelativistic heavy ion collisions by calorimetry and charged particle measurements over a large fraction of 4..pi... Here I want to concentrate on a closer study of nucleus nucleus collisions and recent results from the lead glass spectrometer Saphir. 6 refs., 5 figs.

By combining the results of the hydrodynamic code CON1D and the beam propagation code LASER, we investigate the propagation of high-energy laser beams through vaporizing metallic aerosols in the regime for which the plasma generation becomes important. An effective plasma absorption coefficient allows us to set up a coupled system of equations describing the system consisting of the beam and vapor. 14 refs., 5 figs.

This paper summarizes nuclear-related work in support of the US effort for the International Thermonuclear Experimental Reactor (ITER) Study. Primary tasks carried out during the past year include design improvements of the inboard shield developed for the TIBER concept, scoping studies of a variety of tritium breeding blanket options, development of necessary design guidelines and evaluation criteria for the blanket options, further safety considerations related to nuclear components, and issues regarding structural materials for an ITER device. The blanket concepts considered are the aqueous/Li salt solution, a water-cooled, solid breeder blanket, a helium-cooled, solid-breeder blanket, a blanket cooled by helium containing lithium-bearing particulates, and a blanket concept based on breeding tritium from He/sup 3/. 1 ref., 2 tabs.