The Glass Material Oxidation and Dissolution System (GMODS) is a recently invented process for the direct, single-step conversion of spent nuclear fuel (SNF) to high-level waste (HLW) glass. GMODS converts metals, ceramics, organics, and amorphous solids to glass in a single step. Conventional vitrification technology can not accept feeds containing metals or carbon. The GMODS has the potential to solve several issues associated with the disposal of various US Department of Energy (DOE) miscellaneous SNFs: (1) chemical forms unacceptable for repository disposal; (2) high cost of qualifying small quantities of particular SNFs for disposal; (3) limitations imposed by high-enriched SNF in a repository because of criticality and safeguards issues; and (4) classified design information. Conversion of such SNFs to glass eliminates these concerns. A description of the GMODS, {open_quotes}strawman{close_quotes} product criteria, experimental work to date, and product characteristics are included herein.

New, high-strength, hollow, glass microspheres filled with pressurized hydrogen exhibit storage densities which make them attractive for bulk hydrogen storage and transport. The hoop stress at failure of our engineered glass microspheres is about 150,000 psi, permitting a three-fold increase in pressure limit and storage capacity above commercial microspheres, which fail at wall stresses of 50,000 psi. For this project, microsphere material and structure will be optimized for storage capacity and charge/discharge kinetics to improve their commercial practicality. Microsphere production scale up will be performed, directed towards large-scale commercial use. Our analysis relating glass microspheres for hydrogen transport with infrastructure and economics` indicate that pressurized microspheres can be economically competitive with other forms of bulk rail and truck transport such as hydride beds, cryocarbons and pressurized tube transports. For microspheres made from advanced materials and processes, analysis will also be performed to identify the appropriate applications of the microspheres considering property variables, and different hydrogen infrastructure, end use, production and market scenarios. This report presents some of the recent modelling results for large beds of glass microspheres in hydrogen storage applications. It includes plans for experiments to identify the properties relevant to large-bed hydrogen transport and storage applications, of the …

We present the first direct observation of a supersonic ionization front supported by electron thermal transport in a hot solid density plasma produced by 100fsec-laser-pulse irradiation of a transparent fused quartz target.

We describe a cooperative project between Pacific Northwest Laboratory and Intel on providing low latency communications on the Intel Paragon. Our interest is in developing modules that are tailored to specific types of communication and are optimized for these cases. The modules described are implemented as simple extensions to the Paragon operating system. The first extension supports remote reads, writes, and accumulates on subsections of matrices. This module is intended to be used where the communication pattern is not known until run time. The second extension is designed to support low latency communication for short messages in a pipelined fashion. Finally, an interface for doing highly structured communication where the patterns of communication are well understood ahead of time is described. This is intended to be used in global communications such as global reduction.

The pulsed characteristics of gated, stripline configuration microchannel-plate (MCP) detectors used in X-ray framing cameras deployed on laser plasma experiments worldwide are examined in greater detail. The detectors are calibrated using short (20 ps) and long (500 ps) pulse X-ray irradiation and 3--60 ps, deep UV (202 and 213 nm), spatially-smoothed laser irradiation. Two-dimensional unsaturated gain profiles show < 5% percent long-range transverse variations but up to 3 dB/cm drop in gain parallel to the pulse propagation direction. Up to 50% gain enhancements due to voltage reflection from the bends of a meander stripline geometry and from the ends of conventional straight striplines are also observed. Reproducible gate profiles are obtained with either picosecond X-ray or UV bursts and FWHM extracted with 3 picosecond accuracy. A novel single-shot method for measuring local gate propagation speeds using a tilted MCP is also demonstrated. Detailed output versus input studies indicate a linear dynamic range of 300. At higher irradiances, the gradual transition from linear behavior to hard saturation is gathered over a range of 10{sup 5} in irradiation and fitted using a discrete dynode model. Finally, a pump-probe experiment quantifying for the first time long-suspected gain depletion by strong localized irradiation was …

Radiation damage studies were performed on polystyrene and poly(vinyltoluene) samples containing different concentrations of either an antioxidant (A O-2) or a plasticizer (PP-4). In addition, parallel studies were carried out utilizing samples of these polymers prepared in the presence of cross-linking agents such as NPG, HDA, and DVB. The samples were irradiated using a {sup 60} Co source to total doses of 1 and 10 Mrad, at a dose rate of approximately 1 Mrad/h. Transmittance measurements were recorded before and immediately after irradiation, and after oxygen annealing. These experiments showed that none of these agents improved the radiation resistance of polystyrene and poly(vinyltoluene) with regard to their optical properties.

The Fernald Environmental Management Project (FEMP), formerly the Feed Materials Production Center (FMPC), is a Department of Energy (DOE) site which produced high-quality uranium for military defense beginning in 1951. Production at the FEMP was halted in July 1989. Later that year, the facility was placed on the National Priorities List (NPL). The DOE is currently conducting a Remedial Investigation/Feasibility Study (RI/FS) and other response actions under the Amended Consent Agreement between the US Environmental Protection Agency (USEPA) and the DOE.

Production and injection data from 11 slim holes and 10 large-diameter wells at the Oguni Geothermal Field, Japan, were examined in an effort to establish relationships (1) between productivity of large-diameter wells and slim holes, (2) between injectivity and productivity indices and (3) between productivity index and borehole diameter. The production data from Oguni boreholes imply that the mass production from large diameter wells may be estimated based on data from slim holes. Test data from both large- and smalldiameter boreholes indicate that to first order the productivity and the injectivity indices are equal. Somewhat surprisingly, the productivity index was found to be a strong function of borehole diameter; the cause for this phenomenon is not understood at this time.

Determination of true formation temperature from measured bottom hole temperature is important for geothermal reservoir evaluation after completion of well drilling. For estimation of equilibrium formation temperature, we studied non-linear least squares fitting method adapting the Middleton Model (Chiba et al., 1988). It was pointed out that this method was applicable as simple and relatively reliable method for estimation of the equilibrium formation temperature after drilling. As a next step, we are studying the estimation of equilibrium formation temperature from bottom hole temperature data measured by MWD (measurement while drilling system). In this study, we have evaluated availability of nonlinear least squares fitting method adapting curve fitting method and the numerical simulator (GEOTEMP2) for estimation of the equilibrium formation temperature while drilling.

The effects of an adsorbing phase on the injection of liquid and eventual production of vapor from a low-porosity, vapor dominated geothermal reservoir was studied. The magnitude of delay caused by adsorption, diffusion partitioning, preferential partitioning, and permeability variation were compared. Results were then compared to measured tracer production data at the Geysers to determine the most likely delay mechanism for injected tracer at the Geysers. A one-dimensional numerical model describing vapor flow in a porous medium in the presence of a sorbing phase was used to investigate the delay of injected tracer caused solely by the sorbing phase. An analytical model was used to describe delay effects due to diffusion partitioning of tracer from the vapor phase into the liquid phase. Properties of steam and tracer used in Geysers tracer studies were compared to determine the effects of preferential partitioning. Finally, a streamline model of a tracer study was used to determine the magnitude of permeability delays possible using permeability values measured at the Geysers. It was concluded that adsorption alone has very little effect on the delay of injected tracer indicating that little recharge of the adsorbed mass occurs for a typical injection program at the Geysers. Diffusion …

Through May of 1993, a sequence of reservoir flow tests has been conducted at our Fenton Hill Hot Dry Rock (HDR) test site as part of the Long-Term Flow Testing (LTFT) program. This testing, which extended over an aggregate period of about 8 months, has demonstrated several significant features concerning HDR reservoirs that taken together reflect very positively on the future development of the HDR concept into a viable commercial reality. Of most significance is the demonstrated self-regulating nature of the flow through such a reservoir. Both temperature and tracer data indicate that the flow, rather than concentrating in a few potential direct flow paths, progressively shifted towards more indirect flow paths as the test proceeded. This self-regulating mechanism may be related to the strongly temperature-dependent viscosity of water. Measurements have shown that the reservoir flow impedance is concentrated in the near-wellbore region surrounding the production well. This situation may well be a blessing in disguise since this suggests that the distance between injection and production wells can be significantly increased, with a greatly enhanced access to fractured hot rock, without an undue impedance penalty. However, since the multiply interconnected joints within the HDR reservoir are held open by fluid …

A large number of microearthquake seismograms have been recorded by a downhole, three-component seismic network deployed around the Coso, California geothermal reservoir. Shear-wave splitting induced by the alignment of cracks in the reservoir has been widely observed in the recordings. Over 100 events with body wave magnitude greater than 1.0 from microearthquakes recorded since March of 1992. have been processed. The results show that most events with paths within the critical angle that defines the shear-wave window, display clear shear-wave splitting, and the fast shear waves have predominant polarization directions for most stations. The rose diagrams of fast shear-wave particle motion suggest that there are three predominant fracture strikes (or directions of maximum horizontal stresses) in the Coso geothermal field: N 40°-60°E, N 0°-25°E, and N 25° - 35° W, which are consistent with photographically or magnetically mapped alignments on the surface. From the delay time of split shear waves, we estimate that the crack density in the most active geothermal reservoir area (above 3.00km depth) ranges between 0.030 and 0.055. values commonly found in other hydrocarbon or geothermal reservoirs.

The measurement of the quantity of adsorbed water on geothermal reservoir rocks allows a more realistic estimation of reserves for vapor-dominated geothermal reservoirs. This study measured adsorptioddesorption isotherms of water vapor on rock samples from Calpine Co.'s well MLM-3, both core fragments and well cuttings from Coldwater Creek steamfield and a number of well cuttings from well Prati State 12, Northwest Geysers steam field. Surface areas of these rock samples were measured using nitrogen adsorption at 77K. The results of these measurements suggest that surface area is a crucial factor in determining the amount of water adsorption. Analysis of the water adsorption data indicates that adsorption is the dominant phenomena in the matrix of the reservoir rock at relative pressures below 0.8. Depending on the structure of the rock, capillary condensation contributes considerably to the total water retention at relative pressure between 0.8 and 1.0. However, there is no clear distinction between adsorption and capillary condensation and it is difficult in the experiments to determine when complete saturation occurs. A significant result of these experiments was the demonstration that well cuttings show adsorption characteristics very much like those obtained from core fragments. This should allow further adsorption measurements to be …

The extraction of heat or thermal energy from the Earth -- heat mining -- has the potential to play a major role as an energy supply technology for the 21st century. However, even if reservoir stimulation goals are achieved, the role of heat mining with today's energy prices and development costs is limited to only a small fraction of the earth's surface, specifically to geologically active regions where geothermal gradients are high. This paper examines the prospects for universal heat mining and the types of developments required to make it a reality. A generalized multi-parameter economic model was developed for optimizing the design and performance of hot dry rock (HDR) geothermal systems by linking an SQP nonlinear programming algorithm with a generalized HDR economic model. HDR system design parameters selected for optimization include well depth (or initial rock temperature), geofluid flow rate, number of fractures and injection temperature. The sensitivities of the optimized design parameters, HDR system performance, and levelized electricity price to average geothermal gradient, fractured area/volume, maximum allowable geofluid temperature, reservoir flow impedance, well deviation, and fracture separation have been investigated. Key technical and institutional obstacles to universal heat mining are discussed in a more general context. These …

A numerical study of the Mori geothermal field which consisted of a series of three-dimensional natural state modeling and history matching was carried out with porous models. Finally satisfactory fits both on temperature and pressure of the natural state and on pressure history caused by exploitation were obtained. The results indicate that the deep hot water ascends mainly through the fractures near the caldera wall and the fractures confined to some lithofaces, and some of the ascending hot water flows to the west from the caldera. A sketch of the geological structure, the way of making up the initial numerical model, the way of concluding free parameters, and results of calculations of natural state modeling and history matching for the best numerical model are presented.

Recently, two new developments appeared in the literature on modelling flow and transport in heterogeneous systems. The first one is the use of two different concentration variables namely, the resident and flux concentrations, in tracer studies. The second one involves representing the heterogeneity by means of a frequency disribution function for immobile phase size. Based on these developments, this work involves a classification of the solutions of transport equation in heterogeneous systems. It also demonstrates interpretation of tracer experiments in such systems. Distinguishing between the resident and flux concentration variables prevents the inconsistencies between theoretical solutions and actual conditions of experiments and hence, allows correct interpretation of tracer return profiles. Representing heterogeneities by means of frequency distribution functions allows representing matrix blocks of various sizes likely to exist in a fractured reservoir.

This paper presents a solution for the inverse problem to the flow of tracers in naturally fractured reservoirs. The models considered include linear flow in vertical fractures, radial flow in horizontal fractures, and cubic block matrix-fracture geometry. The Rosenbrock method for nonlinear regression used in this study, allowed the estimation of up to six parameters for the cubic block matrix fracture geometry. The nonlinear regression for the three cases was carefully tested against syntetical tracer concentration responses affected by random noise, with the objective of simulating as close as possible step injection field data. Results were obtained within 95 percent confidence limits. The sensitivity of the inverse problem solution on the main parameters that describe this flow problem was investigated. The main features of the nonlinear regression program used in this study are also discussed. The procedure of this study can be applied to interpret tracer tests in naturally fractured reservoirs, allowing the estimation of fracture and matrix parameters of practical interest (longitudinal fracture dispersivity alpha, matrix porosity phi2, fracture half-width w, matrix block size d, matrix diffusion coefficient D2 and the adsorption constant kd). The methodology of this work offers a practical alternative for tracer flow tests interpretation to …

A long-term flow test was carried out in the Fenton Hill HDR Phase-2 reservoir for 14 months during 1992-1993 to examine the potential for supplying thermal energy at a sustained rate as a commercial demonstration of HDR technology. The test was accomplished in several segments with changes in mean flowrate due to pumping conditions. Re-test estimates of the extractable heat content above a minimum useful temperature were based on physical evidence of the size of the Fenton Hill reservoir. A numerical model was used to estimate the extent of heat extracted during the individual flow segments from the database of measured production data during the test. For a reservoir volume of 6.5x10{sup 6}m{sup 3}, the total heat content above a minimum temperature of 150{degree} C was 1.5x10{sup 15}J. For the total test period at the three sustained mean flowrates, the integrated heat extracted was 0.088x10{sup 15}J, with no discernable temperature decline of the produced fluid. The fraction of energy extracted above the abandonment temperature was 5.9%. On the basis of a constant thermal energy extraction rate, the lifetime of the reservoir (without reservoir growth) to the abandonment temperature would be 13.3 years, in good agreement with the pre-test estimate of …

Economic optimisation of the Ohaaki Geothermal Field dual-flash system indicated the requirement to program for sliding High Pressure turbine inlet pressures and the de-rating of individual wells to Intermediate Pressure. A wellbore simulator was used to generate output curves up to 5 years into the future to enable 'what-if' modelling for maximum electrical generation under different scenarios. The key to predicting future output curves as a function of wellhead pressure was predicting two-phase well productivities as a function of field pressure and enthalpy trends. Using a wellbore simulator to generate inflow pressure curves from output test data and matching measured downhole data showed that the Duns and Ros flow correlation produced a linear response with a consistent relationship to static pressures for most wells. This was used to generate predicted output characteristic curves up to 1998, enabling the modelling of varying turbine inlet pressures.

Steam production data from wells surrounding Unit 13 injection well CA 956A-1 and Unit 16 injection well Barrows-1 were analyzed to estimate annual and cumulative recovery factors due to water injection into these wells. Production and injection data from SMUDGEO#1 and Bear Canyon wellfields were also analyzed to obtain recovery of the injected water in those wellfields. The results of this study may be useful in designing future injection projects in vapor dominated systems.

The relationship between production rates of large diameter geothermal production wells, and slimholes, is studied. The analysis is based on wells completed in liquid-dominated geothermal fields, where flashing occurs either in the wellbore or at the surface. Effects of drawdown in the reservoir, and pressure drop in the wellbore, are included; heat losses from the wellbore to the formation are not presently included in our analysis. The study concentrates on the influence of well diameter on production rate. For situations where the pressure drop is dominated by the reservoir, it is found that the mass flowrate varies with diameter according to W - D{sup {alpha}}, where the exponent {alpha} is a function of reservoir outer radius, well diameter and skin factor. Similarly, when pressure drop in the wellbore is dominant, the scaling exponent was found to be a function of well diameter and pipe roughness factor. Although these scaling laws were derived for single-phase flow, numerical simulations showed them to be reasonably accurate even for cases where flashing occurs in the wellbore.

We conducted feasibility studies of gravity monitoring based upon reservoir simulation. At first, actual field data (although slightly modified) were used for constructing the conceptual model of a geothermal reservoir, particularly for shallow geothermal reservoir case study. Then the possibility of gravity monitoring was confirmed. Secondly, in order to study the possibility of this for deep geothermal reservoir, we constructed simplified models for deep reservoir. Three models were prepared for our feasibility studies. These simulations showed us that we could also get fairly positive results, if we apply a very sensitive and stable gravity monitoring system. As a next step, we will investigate gravity monitoring systems according to our feasibility studies.

Water adsorption in geothermal reservoir materials was investigated by transient flow technique using steam and COz gas. Theoretical and experimental results indicate that water adsorption exists in vapordominated type of reservoir, but experiments in the past have been limited to pure gases. The common presence of CO2, a non-condensible gas, in a geothermal reservoir necessitated a study of the effect of partial CO2 concentration on adsorption. Experimental laboratory work using a crushed Geysers rock sample at low pressure was carried out. Transient pressure exerted by steam pressure inside the sample was measured against time during a desorption process. It was found that the partial presence of CO2 did not significantly affect the adsorption of water.

The effects of dissolved salts (NaCI, KCI, MgCl{sub 2}, CaCI{sub 2}, Na{sub 2}SO{sub 4}, MgSO{sub 4}, and their mixtures) on oxygen and hydrogen isotope partitioning between brines and coexisting phases (vapor and calcite) were experimentally determined at 50-350{degree} C and 300{degree} C, respectively. In liquid-vapor equilibration experiments, for all of the salts studied, the hydrogen isotope fractionation factors between the salt solutions and vapor decreased appreciably (up to 20{permille}) compared to pure water-vapor. Except for KCI solutions at 500 C, the oxygen isotope fractionation factors between salt solutions and vapor were higher (up to 4{permille}) than, or very close to, that of pure water. The observed isotope salt effects are all linear with the molalities of the solutions. Mixed salt solutions mimicking natural geothermal brines exhibit salt effects additive of those of individual salts. The isotope exchange experiments of calcite-water at 300{degree}C and 1 kbar yielded a fractionation factor of 5.9+0.3{permille} for pure water and effects of NaCl consistent with those obtained from the liquid-vapor equilibration experiments. The isotope salt effects observed in this study are too large to be ignored, and must be taken into account for isotopic studies of geothermal systems (i.e., estimation of isotope ratios and temperatures …