Devices become increasingly vulnerable to soft errors as their feature sizes shrink. Previously, soft errors primarily caused problems for space and high-atmospheric computing applications. Modern architectures now use features so small at sufficiently low voltages that soft errors are becoming significant even at terrestrial altitudes. The soft error vulnerability of iterative linear algebra methods, which many scientific applications use, is a critical aspect of the overall application vulnerability. These methods are often considered invulnerable to many soft errors because they converge from an imprecise solution to a precise one. However, we show that iterative methods can be vulnerable to soft errors, with a high rate of silent data corruptions. We quantify this vulnerability, with algorithms generating up to 8.5% erroneous results when subjected to a single bit-flip. Further, we show that detecting soft errors in an iterative method depends on its detailed convergence properties and requires more complex mechanisms than simply checking the residual. Finally, we explore inexpensive techniques to tolerate soft errors in these methods.

From joint power generation conference; New Orleans, Louasiana, USA (16 Sep 1973). The High Temperature Gas Cooled Reactor (HTGR) fuel recycle operation is described. The description includes the HTGR spent fuel shipping system and the proposed method of reprocessing the spent fuel to recover the bred /sup 233/U and /sup 235/U. The process for refabricating the recovered fuel into recycle fuel is also discussed. (auth)

The primary goal of this project was to develop and validate new classes of cost-effective low-permeability ceramic and refractory components for handling molten aluminum in both melting and casting environments. Three approaches were employed with partial to full success to achieve this goal: (1) Develop materials and methods for sealing surface porosity in thermal-shock-resistant ceramic refractories; (2) Develop new ceramic coatings for extreme service in molten aluminum operations, with particular emphasis on coatings based on highly stable oxide phases; and (3) Develop new monolithic refractories designed for lower-permeability applications using controlled porosity gradients and particle size distributions. The results of the research work and the field tests performed utilizing these three approaches are listed below: (1) It was demonstrated that high-density IR heating could be a tool for altering and sealing the surface porosity of fused silica. However, the process was not very cost-effective. (2) A low-cost glaze composition having a coefficient of thermal expansion (CTE) similar to that of a DFS tube was identified and was successfully tested for its integrity and adherence to DFS. Although the glaze acted as a barrier between the molten aluminum and the DFS, persistent porosity and crazing within the glaze affected its performance …

The cost effectiveness of fracture stimulation at The Geysers, the Imperial Valley, and other geothermal resource areas in the United States vas studied using GEOCOM, a computer code for analyzing the impact of completion activities on the life-cycle costs of geothermal wells. Technologies for fracturing the reservoir near the wellbore involve the creation of a pressure pulse in the wellbore by means of either hydraulic or explosive force. The cost of a single fracture stimulation job can vary from $50,000 to over $500,000, with a typical cost of around $300,000. The code shows that additional flow achieved by fracture stimulation must exceed 10,000 pounds per hour for each $100,000 invested in stimulation in order for a fracture treatment to be cost effective. In some reservoirs, this additional flow must be as great as 30,000 pounds per hour. The cost effectiveness of fracturing has not yet been demonstrated in the field. The Geothermal Well Stimulation Program achieved an overall average of about 10,000 pounds per hour for each $100,000 invested.

OAK B188 Initial Screening of Thermochemical Water-Splitting Cycles for High Efficiency Generation of Hydrogen Fuels Using Nuclear Power There is currently no large scale, cost-effective, environmentally attractive hydrogen production process, nor is such a process available for commercialization. Hydrogen is a promising energy carrier, which potentially could replace the fossil fuels used in the transportation sector of our economy. Fossil fuels are polluting and carbon dioxide emissions from their combustion are thought to be responsible for global warming. The purpose of this work is to determine the potential for efficient, cost-effective, large-scale production of hydrogen utilizing high temperature heat from an advanced nuclear power station. Almost 800 literature references were located which pertain to thermochemical production of hydrogen from water and over 100 thermochemical watersplitting cycles were examined. Using defined criteria and quantifiable metrics, 25 cycles have been selected for more detailed study.

Radium (Ra) toxicity in dogs is a cornerstone for the evaluation of plutonium (Pu) toxicity, as it provides a possible link to Pu toxicity in humans. Survival regression models with covariates were used to estimate the risk to survival and the frequency and latency of bone tumor development. It appears for Ra that dose-rate is a more significant contributor to non-survival and bone tumors than is skeletal dose.

Recently a Resistive Magnetohydrodynamics (MHD) package has been added to the KULL code. In order to be compatible with the underlying hydrodynamics algorithm, a new sub-zonal magnetics discretization was developed that supports arbitrary polygonal and polyhedral zones. This flexibility comes at the cost of many more unknowns per zone - approximately ten times more for a hexahedral mesh. We can eliminate some (or all, depending on the dimensionality) of the extra unknowns from the global matrix during assembly by using a Schur complement approach. This trades expensive global work for cache-friendly local work, while still allowing solution for the full system. Significant improvements in the solution time are observed for several test problems.

OAK-B135 A symposium discussing the implications of certain phenomena observed in radiation biology for cancer risk assessment in general. In July of 2002 a workshop was convened that explored some of the intercellular phenomena that appear to condition responses to carcinogen exposure. Effects that result from communication between cells that appear to either increase the sphere of damage or to modify the sensitivity of cells to further damage were of particular interest. Much of the discussion focused on the effects of ionizing radiation that were transmitted from cells directly hit to cells not receiving direct exposure to radiation (bystander cells). In cell culture, increased rates of mutation, chromosomal aberration, apoptosis, genomic instability, and decreased clonogenic survival have all been observed in cells that have experienced no direct radiation. In addition, there is evidence that low doses of radiation or certain chemicals give rise to adaptive responses in which the treated cells develop resistance to the effects of high doses given in subsequent exposures. Data were presented at the workshop indicating that low dose exposure of animals to radiation and some chemicals frequently reduces the spontaneous rate of mutation in vitro and tumor responses in vivo. Finally, it was concluded that …

The U.S. Department of Energy (DOE) has millions of gallons of radioactive liquid and sludge wastes that must be retrieved from underground storage tanks. This waste, in the form of slurries, must be transferred and processed to a final form, such as glass logs. On-line instrumentation to measure the properties of these slurries in real-time during transport is needed in order to prevent plugging and reduce excessive dilution. The results, describes a collaborative effort between Pacific Northwest National Laboratory (PNNL) and the University of Washington to develop a completely new method for using ultrasonics to measure the particle size and viscosity of a slurry. The concepts are based on work in optics on grating-light-reflection spectroscopy (GLRS) at the University of Washington and work on ultrasonic diffraction grating spectroscopy (UDGS) carried out at PNNL. The objective of the research was to extend the GLRS theory for optics to ultrasonics, and to demonstrate its capabilities of UDGS. The proposed ultrasonic method could result in an instrument that would be simple, rugged, and very compact, allowing it to be implemented as part of a pipeline wall at facilities across the DOE complex

Geothermal resource investigations have been conducted for the past four years on Unalaska Island in the Aleutian Chain. The focus of the work has been Makushin Volcano, about 12 miles from the cities of Unalaska and Dutch Harbor. In the summer of 1982, three widely spaced deep temperature gradient holes were drilled which encountered high temperatures. During the summer of 1983, a three inch diameter "slim hole" well, ST-1, was drilled to 1,949 feet. A shallow, low pressure, steam zone and a relatively productive hot water zone at total depth were encountered. The lower zone produced 47,000 lb/hr, limited by reaching critical mass velocity at the orifice. The static bottomhole pressure and temperature were 478 psig and 379{degrees}F, respectively. Analysis of transient pressure and flow data yielded a productivity inex of 3,470 lb/hr/psi and a permeability-thickness of 50,900 md-ft for the three-foot (at the wellbore) lower zone fracture. A preliminary reservoir/wellbore flow evaluation for a possible power plant indicates two commercial-size wells could fuel a 10 megawatt facility.

From July, 1974, to December, 1979, the Laboratory for Nuclear Service (LNS) conducted a study of the feasibility of resource sharing via general - purpose computer networks. Originally, the study focused on methods of implementing an ARPAnet connection for LNS in collaboration with the MIT Information Processing Center (IPC). When it appeared that the most feasible solution for LNS was to access the ARPANET via the MIT Multics system, the investigation expanded to a consideration of the implementation of computer resource sharing via networks. Experiments were performed at various ERDA installations on the ARPANET in using the networks for offloading large calcuations and obtaining access to unique hardware and software. Performance statistics were collected and cost comparisons, made. Both the benefits and barriers of networking were analyzed. The value of electronic mail, teleconferencing, and other forms of computer-aided communication was also investigated. The study demonstrated that resource sharing via networks can provide small computer installations access to computer facilities not available on site. However, it is not adequate substitute for an on-site computer. There must be enough computing power locally to service the average load. Certain types of computations are not effectively done on the network. Use of the network …

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Modeling done at Pacific Northwest National Laboratory (PNNL) in FY2000 predicted improved sensitivity for remote chemical detection by differential absorption lidar (DIAL) if frequency-modulated (FM) lasers were used. This improved sensitivity results from faster averaging away of speckle noise and the recently developed quantum cascade (QC) lasers offer the first practical method for implementing this approach in the molecular fingerprint region of the infrared. To validate this model prediction, a simple laboratory bench FM-DIAL system was designed, assembled, tested, and laboratory-scale experiments were carried out during FY2001. Preliminary results of the FM DIAL experiments confirm the speckle averaging advantages predicted by the models. In addition, experiments were performed to explore the use of hybrid QC - CO2 lasers for achieving sufficient frequency-modulated laser power to enable field experiments at longer ranges (up to one kilometer or so). This approach will allow model validation at realistic ranges much sooner than would be possible if one had to first develop master oscillator - power amplifier systems utilizing only QC devices. Amplification of a QC laser with a CO2 laser was observed in the first hybrid laser experiments, but the low gain and narrow linewidth of the CO2 laser available for these experiments …

Injection-backflow tracer testing on a single well is not a commonly used procedure for geothermal reservoir evaluation, and, consequently, there is little published information on the character or interpretation of tracer recovery curves. Two field experiments were conducted to develop chemical tracer procedures for use with injection-backflow testing, one on the fracture-permeability Raft River reservoir and the other on the matrix-permeability East Mesa reservoir. Results from tests conducted with incremental increases in the injection volume at both East Mesa and Raft River suggests that, for both reservoirs, permeability remained uniform with increasing distance from the well bore. Increased mixing during quiescent periods, between injection and backflow, at Raft River suggest an area near the well bore that has a hydrologic character different from the far well bore environment. Increased flow rates for East Mesa testing resulted in a general decrease in mixing. Comparison of recovery curves from the Raft River reservoir with those from the East Mesa reservoir suggests that mixing is greatest, and therefore permeability is greatest, in the fractured reservoir. These test results indicate that injection-backflow testing with tracers can be used successfully to characterize flow in the near-well bore environment.

Mofete field, located near Naples, in southern Italy, lies within the large Campi Flegrei caldera. Drilling for geothermal fluids was carried out unsuccessfully in 1939-1954. AGIP, in joint venture with the national utility ENEL, after intensive exploration efforts, resumed drilling at the end of 1978; several new deep wells indicate the presence of a water dominated field in Mofete with three reservoirs (only the shallowest of which was reached by previous wells). The deepest aquifer, tapped by well Mofete 5 at the depth of about 2700 m, contains hypersaline fluids (about 516000 ppm TDS at atmospheric conditions corresponding to about 150000 ppm in the reservoir) with a bottom hole temperature of about 360{degrees}C. The intermediate level, reached by well Mofete 2 at 1900 m depth, is characterized by low salinity fluids (about 38000 ppm TDS at the surface corresponding to 18000 ppm calculated in the reservoir) with a reservoir temperature of 340{degrees}C. The uppermost reservoir, tapped by wells Mofete 1, 3D, 7D, 8D and 9D ranges between 550 and 1500 m depth and has water with salinity ranging from 40000 to 76000 ppm TDS at the surface corresponding to 28000 to 52000 ppm in the reservoir with a bottom temperature …

Weight increases during the oxidation of irradiated foils of pure copper were greater than for unirraaiated specimens. Enhanced reactivity appeared to be strongest in the thin-film region up to about 5 mu g/cm/sub 2/. Oxide film (Cu/ sub 2/O) thickness for both irradiated and unirradiated specimens was approximately 1200 A. Radiation did not affect the reduction of Cu/sub 2/O during the induction period (period in which the reduction proceeds very slowly or not at all). In later stages of the reduction process, a serious lack of reproducibility was observed. Radiation effects on films of Cu/sub 2/O formed by prior oxidation of the copper substrate decreased the kinetics of secondary oxidation. The secondary oxidation curve exhibited a large gap at the point of interrnption for irradiation. The development of an automatic recording microbalance of high sensitivity and a furnace for studies in reactor radiation fields is reported. Measurements were made of the electrode potentials of irradiated (5.5 x 10/sup 19/ neutrons cm/sup -2/) copper, aluminum, magnesium, and zirconium. Cell potentials were found to be dominated by the oxide films formed on the electrode surfaces. The results indicate that radiation does affect the local anode reaction potential. No significant difference between the …

The Sensor Research & Development Corporation (SRD) has undertaken the development of a Continuous Emissions Monitor (CEM) for mercury based on the technique of Cavity Ring-Down Spectroscopy (CRD). The project involved building an instrument for the detection of trace levels of mercury in the flue gas emissions from coal-fired power plants. The project has occurred over two phases. The first phase concentrated on the development of the ringdown cavity and the actual detection of mercury. The second phase dealt with the construction and integration of the sampling system, used to carry the sample from the flue stack to the CRD cavity, into the overall CRD instrument. The project incorporated a Pulsed Alexandrite Laser (PAL) system from Light Age Incorporated as the source to produce the desired narrow band 254 nm ultra-violet (UV) radiation. This laser system was seeded with a diode laser to bring the linewidth of the output beam from about 150 GHz to less than 60 MHz for the fundamental beam. Through a variety of non-linear optics the 761 nm fundamental beam is converted into the 254 nm beam needed for mercury detection. Detection of the mercury transition was verified by the identification of the characteristic natural isotopic …

Research progress is reported in the following areas: (1) the delineation of the boundary separating elastic-brittle and transient-1 semibrittle behavior of granite and of its volcanic and metamorphic equivalents, rhyolite and granite gneiss; (2) the variation of fracture permeability in Sioux Quartzite, Westerly Granite and a fine-1 grained gabbro as a function of effective pressure and hydrothermal alterations; and (3) determine the mechanical properties of selected rocks at high temperatures and pressures. (ACR)

This report summarizes the results obtained from a series of petrofabric analyses of deformed and undeformed salt specimens. The specimens were originally obtained from a bedded salt mine near Lyons, Kansas where Project Salt Vault was conducted and from an operating salt mine in a domal salt formation at Jefferson Island, LA. Specimens from each site were tested in quasi-static triaxial compression and triaxial creep at RE/SPEC Inc. Subsequently, specimens which exhibited representative macroscopic deformational characteristics were selected for these fabric studies. The purpose of the petrofabric studies is to assist in developing a fundamental physical understanding of the mechanical results. Undeformed specimens were examined by optical techniques to determine preferred crystal orientations. Deformed specimens were studied by petrofabric techniques in order to characterize the deformational mechanisms. Finally, the results of the petrofabrics are compared to the mechanical data.

The Department of Energy (DOE) selected Caustic-Side Solvent Extraction (CSSX) as the preferred technology for the removal of radioactive cesium from High-Level Waste (HLW) at the Savannah River Site (SRS). Before the full-scale Salt Waste Processing Facility (SWPF) becomes operational, the Closure Business Unit (CBU) plans to process a portion of dissolved saltcake waste through a Modular CSSX Unit (MCU). This work was derived from Technical Task Request SP-TTR-2004-00013, ''Gamma Monitor for MCU''. The deliverables for this task are the hardware and software for the gamma monitors and a report summarizing the testing and acceptance of this equipment for use in the MCU. Gamma-ray monitors are required to: (1) Measure the Cs-137 concentration in the decontaminated salt solution before entering the DSS (Decontaminated Salt Solution) Hold Tank, (2) Measure the Cs-137 concentration in the strip effluent before entering the Strip Effluent Hold Tank, (3) Verify proper operation of the solvent extraction system by verifying material balance within the process (The DSS Hold Tank Cs-137 concentration will be very low and the Cs-137 concentration in the Strip Effluent Hold Tank will be fifteen times higher than the Cs-137 concentration in the Feed Tank.) Sodium iodide monitors are used to measure the …

The Cerro Prieto geothermal field is a liquid-dominated geothermal reservoir of complex geological and hydrological structure. It is located at the southern end of the Salton-Mexicali trough which includes other geothermal anomalies as Heber and East Mesa. Although in 1973, the initial power plant installed capacity was 75 MW of electrical power, this amount increased to 180 MW in 1981 as field development continued. It is expected to have a generating capacity of 620 MW by the end of 1985, when two new plants will be completely in operation. Questions about field deliverability, reservoir life and ultimate recovery related to planned installations are being presently asked. Numerical modeling studies can give very valuable answers to these questions, even at the early stages in the development of a field. An effort to simulate the Cerro Prieto geothermal reservoir has been undergoing for almost two years. A joint project among Comision Federal de Electricidad (CFE), Instituto de Investigaciones Electricas (IIE) and Intercomp of Houstin, Texas, was created to perform reservoir engineering and simulation studies on this field. The final project objective is tosimulate the behavior of the old field region when production from additional wells located in the undeveloped field zones will …

We present a two-steps synthesis route that yields nanometer size crystalline germanium in the form of a black powder. It relies on high temperature decomposition of tetraethylgermane (TEG) in organic solvents. The presence of pure germanium with diamond structure is unambiguously attested by powder XRD measurements. Low resolution TEM indicates that the particles are between {approx}5 to 30 nm in size depending on the synthesis conditions. The as-synthesized Ge powders can be stored in air for months and no oxidation occurs. The Ge powders are sparingly soluble in conventional solvents because Ge nanocrystals are likely embedded in a matrix, composed mainly of C=C, C-C, and C-H bonds. The presence of residual organic by-products impedes probing of the optical properties of the dots. Also, we discuss drawbacks and open challenges in high temperature solution synthesis of Ge nanocrystals that could also be faced in the synthesis of Si nanocrystals. Overall, our results call for a cautious interpretation of reported optical properties of Ge and Si nanocrystals obtained by high temperature solution methods.

This paper consists of two parts and an appendix. In the first part a review is made of the geothermal activity in Italy from 1975 to 1982, including electrical and non-electrical applications. Remarks then follow on the trends that occurred and the operational criteria that were applied in the same period, which can be considered a transitional period of geothermal development in Italy. Information on recent trends and development objectives up to 1990 are given in the second part of the paper, together with a summary on program activities in the various geothermal areas of Italy. The appendix specifically reviews the main reseroir engineering activities carried out in the past years and the problems likely to be faced in the coming years in developing Itallian fields.

General features of the geometry of Los Azufres reservoir have been defined through the mapping of hydrothermal mineral alteration zones. Hydrothermal alteration has been studied in cuttings and drill cores from most of the active wells. X-ray diffraction microprobe analysis and classical optical methods have been employed for the identification of primary and authigenic minerals in fresh and altered samples. Observed patterns of alteration have been correlated with temperature and patterns of fluid circulation. The resulting model depicts a body of geothermal fluid at depth, which ascends and discharges through two main fracture systems. These two circulation zones are characterized by concentric aureoles of increasing hydrothermal alteration towards quasivertical axes. The overall pattern could be described as a dome structure produced by the abnormal thermal gradient, distorted by the effects of active upward circulation of the fluids.