The Advanced Test Accelerator (ATA) is a recent development in the field of charged particle beam research at Lawrence Livermore National Laboratory. With this experimental apparatus, researchers will characterize intense pulses of electron beams propagated through air. Inherent with the ATA concept was the potential for exposure to hazards, such as high radiation levels and hostile breathing atmospheres. The need for a comprehensive safety program was mandated; a formal system safety program was implemented during the project's conceptual phase. A project staff position was created for a safety analyst who would act as a liaison between the project staff and the safety department. Additionally, the safety analyst would be responsible for compiling various hazards analyses reports, which formed the basis of th project's Safety Analysis Report. Recommendations for safety features from the hazards analysis reports were incorporated as necessary at appropriate phases in project development rather than adding features afterwards. The safety program established for the ATA project faciliated in controlling losses and in achieving a low-level of acceptable risk.

The gasdynamic partial differential equations (PDE's) governing the motion of an ablatively accelerated target (rocket) contain an inertial force term that arises from acceleration of the reference frame in which the PDE's are written. We give a simple, intuitive description of this effect, and estimate its magnitude and parametric dependences by means of approximate analytical formulas inferred from our computer hydrocode calculations. Often this inertial term is negligible, but for problems in the areas of laser fusion and laser equation of state studies we find that it can substantially reduce the attainable hydrodynamic efficiency of acceleration and implosion.

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The Tandem Mirror Experiment-Upgrade (TMX-U) machine consists of seven major machine subsystems: magnet system, neutral beam system, microwave heating (ECRH), ion heating (ICRH), gas fueling, stream guns, and vacuum system. Satisfactory performance of these subsystems is necessary to achieve the experimental objectives planned for TMX-U operations. Since the performance quality of the subsystem is important and can greatly affect plasma parameters, a 233-channel instrumentation system has been installed. Data from the instrumentation system are acquired and stored with the plasma diagnostic information. Thus, the details of the machine performance are available during post-shot analysis. This paper describes all the machine-parameter-instrumentation hardware, presents some typical data, and outlines how the data are used.

A Photovoltaic Metallization Research Forum, under the sponsorship of the Jet Propulsion Laboratory's Flat-Plate Solar Array Project and the US Department of Energy, was held March 16-18, 1983 at Pine Mountain, Georgia. The Forum consisted of five sessions, covering (1) the current status of metallization systems, (2) system design, (3) thick-film metallization, (4) advanced techniques and (5) future metallization challenges. Twenty-three papers were presented.

Complementary broad-band instruments have been developed to measure time dependent, absolute soft x-ray spectra at the Lawrence Livermore National Laboratory (LLNL) Nd glass laser irradiation facilities. Absolute flux measurements of x rays emitted from laser-produced plasmas are important for understanding laser absorption and energy transport. We will describe two new 10-channel XRD systems that have been installed at the LLNL Novette facility for use in the 0.15- to 1.5-keV range. Since XRD channel time response is limited by available oscilloscope performance to 120 ps, a soft x-ray streak camera has been developed for better time resolution (20 ps) and greater dynamic range (approx.10/sup 3/) in the same x-ray energy region. Using suitable filters, grazing incidence mirrors, and a gold or cesium-iodide transmission cathode, this streak camera instrument has been installed at Novette to provide one broad and four relatively narrow channels. It can also be used in a single channel, spatially discriminating mode by means of pinhole imaging. The complementary nature of these instruments has been enhanced by locating them in close proximity and matching their channel energy responses. As an example of the use of these instruments, we present results from Novette 2..omega..(0.53 ..mu..m) gold disk irradiations at 1 …

In the development of geothermal sources for power generation, production of geothermal fluids as well as reinjection becomes an important aspect for significant heat extraction from the reservoir rock. The purpose of this work was to understand how cold water injection in five spot pattern affected the temperature distributions and production pressures in a physical model with a constant temperature heat source. The production and injection rates were varied as well as their respective depths. The model is a hot water dominated system with crushed limestone of 0.6-0.9 cm particle size as the reservoir rock, which had 40% porosity, 58 darcy permeability. The analysis revealed that injection rate should be at least 2/3 of production rate (measured as condensed water) so that the pressure decline at the producing end was stopped. Heat extraction from the system was high when injection was done towards the top of the model while production horizon was deeper.

For a description and analysis of the flow they consider the conservation equations of the two phases separately, but in thermal and mechanical equilibrium, coupled by the itnerface shear forces (two fluid model, drift flux model). Coupling may be weak or strong, depending on Froude and Mach numbers of the flow. The fluid is highly compressible, not because the individual phases move at such speeds that their individual density changes are significant but because evapiration (phase change) results in large density changes of the system at moderate pressure or temperature changes once flashing occurs. The slip between the phases is caused by unequal wall shear stress, acceleration of the fluid or gravitational forces and is hindered by the interface interaction. if they denote by {gamma} the ratio of the liquid density to the vapor density and by {sigma} the ratio of the vapor speed to the liquid speed they find that in horizontal flows {sigma} = {gamma}{sup 1/2} yields the maximum slip (neglecting acceleration effects) that can be reached with no interface force acting (assuming equal friction coefficients for both phases at the wall). If one investigates the conditions of thermodynamic flow similarity between different substances in two phase flow, …

The concept of relative permeability is the key concept in extending Darcy's law for single phase flow through porous media to the two-phase flow regime. Relative permeability functions are needed for simulation studies of two-phase geothermal reservoirs. These are poorly known inspite of considerable theoretical and experimental investigations during the last decade. Since no conclusive results exist, many investigators use ad hoc parametrization, or adopt results obtined from flow of oil and gas (Corey, 1954). It has been shown by Reda and Eaton (1980) that this can lead to serious deficiencies. Sensitivity of the relative permeability curves for prediction of mass flow rate and flowing enthalpy into geothermal wells has been studied by many investigators (e.g. Eaton and Reda (1980), Bodvarsson et al (1980), Sun and Ershagi (1979) etc.). It can be concluded from these studies that the beehavior of a two-phase steam/water reservoir depends greatly on the relative permeability curves used. Hence, there exists a need for obtaining reliable relative permeability functions.

Data from a seven week pressure interference test in the Klamath Falls, Oregon geothermal resource have been analyzed. The data indicate that productive wells are fed by a highly permeable fracture network and that the less permeable matrix blocks contribute significantly to the reservoir storage capacity. Detailed analysis of data from two wells is presented. Data from both of the wells yield a reservoir permeability-thickness (kh) of approximately 1.3x10{sup 6} md-ft and a storativity of 6.8x10{sup -3} ft/psi. The parameters ({lamda} and {omega}), which are determined by the distribution of permeability and storativity between the matrix and fractures, vary by more than an order of magnitude. A sensitivity study shows that for these wells, the pressure transients are not very sensitive to the distribution of permeability and storativity between the fractures and matrix blocks. No hydrologic boundaries were detected during the test. This indicates that the fault which supplies hot water to the shallow hydrothermal system does not behave according to the cassical model of either a barrier or constant potential boundary.

Large volume hydraulic injections into the Carnmenellis granite have been completed at the CSM Hot Dry Rock Project during the period October 1982 to July 1983, with small volume injections before and after this period. The effects of the injections on the hydraulic properties of the rock mass have been estimated by pressure transient analysis. The growth of the reservoir zone was tracked with microseismic locations, and the growth mechanism modeled with the computer program FRIP. The limited duration of the transients amenable to analysis and the tendency for growth below the injection zone meant that the interpretations could only describe hydraulic conditions within about 100 m of the wellbores. The effect of the large volume injections was to increase permeability values from less than 100 {micro}d to greater than 5 md, and to decrease skin values from about -3 to about -6. The FRIP modeling explained the observed reservoir growth in plan with reference to measured in-situ stresses, jointing and rock properties and showed some of the limitations of continuum modeling.

Five new gas geothermometers are introduced. They are useful for predicting subsurface temperatures in water dominated geothermal systems. The geothermometers use data on CO{sub 2}, H{sub 2}S and H{sub 2} concentrations in fumarole steam as well as CO{sub 2}/H{sub 2} and H{sub 2}S/H{sub 2} ratios. It is demonstrated that the gas composition of fumarole steam may be used with or withour drillhole data to evaluate steam condensation in the upflow zones of geothermal systems. Uncertainty exists, however, in distinguishing between the effects of steam condensation and phase separation at elevated pressures. The gas content in steam from discharging wells and the solute content of the water phase can be used to evaluate which boiling processes lead to "excess steam" in the discharge and at which temperature this "excess steam" is added to the fluid moving through the aquifer and into the well. Examples, using field data, are given to demonstrate all the mentioned applications of geothermal chemistry.

In geothermal wells injection tests are commonly used to obtain well and reservoir data. These tests are typically conducted in a series of step rates followed or preceded by a complete shutin. Usually the temperature of the injected fluid is different from that of the reservoir fluid. Because of the strong temperature dependence of fluid viscosity and to a lesser extent, fluid density, nonisothermally related pressure responses must be considered. The nonisothermal isjectivity index obtained from these tests depends on the mobility ratio of the cold region to the hot reservoir and the extent of the cold spot. This paper proposes a method which accounts for these effects and relates the nonisothermal injectivity index to the isothermal injectivity index.

The development of reliable spinner tools may help avoid much of the ambiquity which often accompanies well tests in geothermal wells, due to interlayer flows through the well bore. However, the use of both pressure and flow rate changes requires new methods of well test interpretation. The Stanford Geothermal Program has been developing microcomputer-based techniques for the simultaneous analysis of pressure and flow rate measurements. There are two key steps in the procedure. Firstly, the non-linear regression is achieved by calculating the gradients of the response (with respect to the unknown reservoir parameters) in Laplace space, and inverting numerically. Secondly, the variable flow rate is represented in terms of a superposition of many step changes - this was found to work better than a spline fit to the data. One problem was encountered when attempting to analyze data in which the spinner "stalled", causing a jump to zero flow rate. The method shows great promise in that the degrees of freedom on the interpretation are greatly reduced, the well bore storage effect disappears, and inter-feed flows do not affect the results.

The present situation of the geothermal field developments in Japan is such that eight geothermal power stations are being operated, while there are sill many geothermal areas to be explored. Up to this day, the target of geothermal exploration has mainly been the areas by surface geological survey and the existing geothermal reservoirs are located not deeper than 1,500m depth. Recent geothermal energy development shows a trend from the study on vapor dominated of liquid dominated hydrothermal resources in shallow zones to that on hydrothermal resources in deeper zones. Exploration wells of 3,000m depth class have been drilled in Japan.

Achievements and problem areas are reviewed with respect to various engineering implications of geothermal field development in the European Community (EC). Current and furture development goals address three resource settings. (a) low enthalpy sources (30-150{degrees}C), an outlook common to all Member states as a result of hot water aquifers flowing in large sedimentary units with normal heat flow, widespread thoughout the EC; (b) high enthalpy sources (<150{degrees}C) in areas of high heat flow which, as a consequence of the geodynamics of the Eurasian plate, are limited to Central and South-West Italy and to Eastern Greece; (c) hot dry rocks (HDR), whose potential for Europe, and also the difficulties in implementing the heat mining concept, are enormous. A large scale experiment conducted at medium depth in Cornwall (UK) proves encouraging though. It has provided the right sort of scientific inputs to the understanding of the mechanics of anisotropic brittle basement rocks.

A surface electrical potential system was fielded during the chemical stimulation of the Rossi 21-19 well in the Beowawe Geothermal Field. The technique, which measures variations in resistivity resulting from the flow of conductive fluid into the reservoir, was not only shown to be highly sensitive, not only to the chemical treatment, but also to the in situ conductive zones before any acid injection. A review of the experiment and a preliminary interpretation of the data are presented. The data provide convincing evidence that it should be possible to map the treated zone as well as the primary pretreatment in situ conductive zones.

The present exploitation conditions of the Ahuachapan field are discussed. The high well density in a small area has resulted in a significant reservoir pressure decrease due to the inherent reservoir over-exploitation. The average pressure in the exploitation zone has decreased from the 1975 value of 34 kg/cm{sup 2} to the May 1983 value of 23 kg/cm{sup 2}. The production decline characteristics of the Ahuachapan wells were examined, concluding that all wells but Ah-22 show exponential decline. The cumulative production-reinjection for the field up to April 1983 is 159.090 x 10{sup 6} tons, and 37.592 x 10{sup 6} tons, respectively. The effect of reinjection upon field behavior is evident when observing the pressure decline characteristics of the field. It is seen that for indection fraction related to total mass extracted above 30 percent, the average decline pressure in the production area becomes approximately stabilized. If this condition is not met the reservoir pressure decreases sharply. From this finding it is concluded that a careful and properly planned reinjection program is a must for the field. The observed temperature reduction in some of the wells seems to be the result of two operating mechanisms. First, we have the pressure decline that …

Geothermal wells discharging hundreds of tons/hour of steam-water mixtures may be supplied at depth from one very narrow crack of width 1 to 2 mm, or alternatively, from some hundreds of hairline cracks. In the former case, turbulent flow takes place out to tens of meters from the well while the sum of frictional and kinetic pressure-drop indicates the flashing distance to be of the order of 10 cm from the well wall for pressure-temperature equilibrium. However it is unlikely that equilibrium obtains because of the high water velocity (order of 100 m/s) near the well giving no time for bubble nucleation. Flashing and hence mineral deposition are therefore not at all likely in the crack but can occur within the well from the crack horizon upwards. In the case of a multitude of fine cracks giving the same total flow, streamline conditions prevail over the flow path with the flash front a meter or so from the well, hence deposition is a possibility.

A freshly flashed geothermal liquid, previously dosed with inhibitor and super-saturated with calcite was injected into another well where it displaced an unflashed counterpart of itself around the wellbore. Back-production of the injectate, and subsequently the native fluid, has yielded data for the rate that a scale inhibitor is degraded after injection. The circumstance also displays a novel mechanism whereby two fluids that do not physically mix never the less reactive with one another through the reservoir rock's serving a role of intermediary. The results have been further interpretated to conclude that in some circumstances a short lifetime for the scale inhibitor is not necessarily a problem for long-term injection.

In order to evaluate geothermal reserves, it is necessary to estimate the porosity-thickness product of the reservoir. This paper deals with the method for estimating the porosity-thickness product of geothermal reservoirs by means of combining well interference and pressure buildup tests. A field study from the Chingshui geothermal area in Taiwan is given to illustrate the application of the method.

The hydrothermal system in the vicinity of Lassen Volcanic National Park contains a central region of fluid upflow in which steam and liquid phases separate, with steam rising through a parasitic vapor-dominated zone and liquid flowing laterally toward areas of hot spring discharge south of the Park. A simplified numerical model was used to simulate the 10,000-20,000 year evolution of this system and to show that under certain circumstances fluid withdrawal from hot-water reservoirs south of the Park could significantly alter the discharge of steam from thermal areas within the Park.

This paper contains the experience gained after one year operating five 5 MW portable, back-pressure, geothermal power plants at Los Azufres. A brief description of the field and te equipment is given. Cost figures of the whole installation and a list of what they believe are the advantages and disadvantages is also presented. The main conclusion is that the use of this type of turbogenerators is quite attractive in new undeveloped fields and also in countries with financial problems where initial capital cost investments must be kept as low as possible at the expenses of long term steam consumption.

Many problems concerning the origin and exploitation of geothermal reservoirs demonstrate the need for models of reactive-solute transport. Of particular interest to us is the coupling between dissolution/precipitation reactions and transient-flow behavior. In an effort to account for observed flow-rate reductions during experiments on samples of granite held in a temperature gradient (summarized at this meeting in 1981 by Moore and others), we examine the effect of quartz precipitation on fluid flow. Our results confirm earlier inerences that reactions responsible for porosity reduction were affected by kinetic factors. Although our results show substantial flow-rate reductions, we are unable to reproduce measured silica concentrations of the outlet fluid by considering the behavior of silica phases without regard for that of the feldspars and micas.