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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 973 records · Page 54
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Anaerobic co-digestion of sugarcane press mud with vinasse on methane yield

Highlights: • Press mud and vinasse co-digestion was investigated. •Methane yield during co-digestion was 64% higher to mono-digestion. • Press mud and vinasse co-digestion increased process stability. - Abstract: The conversion efficiency of high solids waste digestion as sugarcane press mud (P) may be limited due to hydrolysis step. The option of co-digestion with vinasse, main liquid waste generated from ethanol production, was investigated under batch regime at mesophilic conditions (37.5 ± 1 °C) and the best mixture was evaluated under semicontinuous regime in stirred-tank reactors. The maximum values for methane yield in batch tests were for V{sub 75}/P{sub 25} and V{sub 50}/P{sub 50} mixtures (on basis of the chemical oxygen demand (COD) percentage added in the mixture), with an average value of 246 N mL CH{sub 4} g{sup −1} COD{sub fed}, which was 13% higher than that of press mud alone. A highest methane production rate of 69.6 N mL CH{sub 4} g{sup −1} COD{sub fed}{sup −1} d{sup −1} was obtained for the mixtureV{sub 75}/P{sub 25}. During the experiment carried out in CSTR reactors, the organic loading rate (OLR) was increased from 0.5 up to 2.2 g VS L{sup −1} d{sup −1}. Methane yields of 365 L CH{sub 4} kg{sup −1} VS and biogas productivities of 1.6 L L{sup −1} were obtained in co-digestion, which was 64% higher in comparison to mono-digestion. The performance of the process in mono-digestion was less stable than in co-digestion, with a significant fall of methane yield to 1.8 kg VS m{sup −3} d{sup −1}, and a partial inhibition of the methanogenic archaeas when the OLR was increased up to 2.2 kg VS m{sup −3} d{sup −1}. The co-digestion of vinasse with press mud is a good option for the treatment of streams at the alcohol-sugar industry.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2012

Energy characteristics of beam-plasma interaction in a closed volume

Energy exchange between an electron beam and plasma during a beam-plasma discharge in a closed cavity excited by the electron beam is analyzed using computer simulations by the KARAT code. A method allowing one to analyze the beam-plasma interaction in the quasi-steady stage of the discharge is proposed. Qualitative characteristics of energy exchange (such as beam energy losses and the energy distributions of beam electrons and plasma particles leaving the discharge) both during spontaneous discharge excitation and in the presence of initial beam modulation by regular or noiselike signals are determined. The results obtained enable one to estimate the energy characteristics of a plasma processing reactor based on a beam-plasma discharge.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2015

Radiation-Hardened Circuitry Using Mask-Programmable Analog Arrays. Final Report

As the recent accident at Fukushima Daiichi so vividly demonstrated, telerobotic technologies capable of withstanding high radiation environments need to be readily available to enable operations, repair, and recovery under severe accident scenarios where human entry is extremely dangerous or not possible. Telerobotic technologies that enable remote operation in high dose rate environments have undergone revolutionary improvement over the past few decades. However, much of this technology cannot be employed in nuclear power environments due the radiation sensitivity of the electronics and the organic insulator materials currently in use. This is the final report of the activities involving the NEET 2 project Radiation Hardened Circuitry Using Mask-Programmable Analog Arrays. We present a detailed functional block diagram of the proposed data acquisition system, the thought process leading to technical decisions, the implemented system, and the tested results from the systems. This system will be capable of monitoring at least three parameters of importance to nuclear reactor monitoring: temperature, radiation level, and pressure.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2019

Post-Irradiation Examination of Low Neutron Dose Metal Fuel Parallelepipeds

Metal fuel samples were subjected to series of low-dose irradiations at the High Flux Isotope Reactor (HFIR) Hydraulic Tube (HT) Facility in FY 2012. The objective of these irradiations was to further fundamental scientific understanding of phenomena involved in the evolution of metal fuels microstructures under irradiation based on separate effects testing of various factors including elemental composition, temperature, and neutron fluence. These data would then be used to inform theoretical models for in-service performance of metallic fuels. Because metallic fuels are generally considered for fast spectrum reactor designs, specialized irradiation capsules, referred to as “rabbits,” were designed with gadolinium thermal neutron shielding surrounding the samples. This design resulted in a fast-neutron spectrum comparable with the nominal in-reactor conditions for metal fuels.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2024

EverGREEN 2045: An Energy Mix to Decarbonize Washington State

Washington State’s future resource mix is likely to be comprised of intermittent renewables and carbon-free generation including hydropower by 2045. Generation will likely be comprised of wind, solar photovoltaic (PV), batteries, pumped storage hydropower (PSH), existing nuclear power plants, and potentially enhanced geothermal systems and advanced nuclear reactor technologies. To assess the cost and stability of the future resource mix, we partner with X-energy (advanced reactor design) and AltaRock Energy (enhanced geothermal system) for proprietary cost data. After estimating the costs of these two new technologies, we design plausible future resource mix scenarios to meet Washington State’s Clean Energy Transformation Act which transitions the state to carbon-free generation by 2045. We assess the cost and stability of the future resource mix with power system analysis tools, finding revenues are sufficient to cover variable operating and maintenance costs for most technologies providing power in 2030 and 2045, but capacity payments or power purchase agreements will likely be necessary for flexible resources, including enhanced geothermal systems and advanced nuclear reactors, to participate in the future resource mix.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
NASA NTRS1971

Shuttle APS propellant thermal conditioner study

The conditioner design concept selected for evaluation consists of an integral reactor and baffle-type heat exchanger. Heat exchange is accomplished by flowing reactor hot gases past a series of slotted and formed plates, through which the conditioned propellant flows. Heat transfer analysis has resulted in the selection of a reactor hot gas nominal mixture ratio of 1.0, giving a combustion temperature of 1560 F with a hydrogen inlet temperature of 275 R. Worst case conditions result in a combustion gas temperature of 2060 F, satisfying the condition of no damage to the conditioner in case of failure to flow cold fluid. In addition, evaluation of hot gas flow requirements and conditioner weight has resulted in the selection of a reactor hot gas exhaust temperature of 750 R.

Fulton, D. L.↗
NASA NTRS1972

The synthesis of starch from carbon dioxide using isolubilized stabilized enzymes

Systems for artificial manufacture of starch and for delineation of technological areas, and the rationale for studying them are considered. A discussion of the enzyme-catalyzed routes of synthesis available and a choice as to the most promising route are presented. A discussion of the enzymes involved, of enzyme insolubilization technology, and of possible engineering approaches, with examples in the form of model calculations for both reactors and separators, are also presented.

Bassham, J. A.↗
NASA NTRS1988

Flexible Ceramic-Insulated Cable

Cable withstands heat, radiation, and oxidation. Ceramic beads electrically insulate copper conductor from sheath of copper tape. Also suitable for furnaces, nuclear reactors, and robots operating in hot, radioactive environments.

Bouquet, Frank L.↗
NASA NTRS1991

Technology and applications of space nuclear power

Requirements for a number of potential NASA civil space missions are addressed, and the nuclear power technology base to meet these requirements is described. Particular attention is given to applications of space nuclear power to lunar, Mars, and science missions and the technology status of space nuclear power with emphasis on dynamic isotope and space nuclear reactor power systems.

Reck, Gregory M.↗
DOE OSTI2015

Isotopic molybdenum total neutron cross section in the unresolved resonance region

Accurate isotopic molybdenum nuclear data are important because molybdenum can exist in nuclear reactor components including fuel, cladding, or as a high yield fission product. High-resolution time-of-flight neutron transmission measurements on highly enriched isotopic metallic samples of 95 Mo, 96 Mo, 98 Mo, and 100 Mo were performed in the resonance energy range from 1 to 620 keV. The measurements were taken with the newly developed modular 6 Li-glass transmission detector positioned at the 100-m experimental flight station. For the unresolved energy region (URR), new comprehensive methods of analysis were developed and validated in order to obtain accurate neutron total cross-section data from the measurement by correcting for background and transmission enhancement effects. Average parameters and fits to the total cross section for 95 Mo were obtained using the Hauser-Feshbach statistical model code FITACS, which is currently incorporated into the SAMMY code. Moreover, fits to the experimental data deviate from the current evaluated nuclear data file/B-VII.1 isotopic Mo evaluations by several percent in the URR.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2012

Scientific Upgrades at the Oak Ridge National Laboratory High Flux Isotope Reactor

The United States Department of Energy is sponsoring a number of projects that will provide scientific upgrades to the neutron science facilities associated with the High Flux Isotope Reactor (HFIR) located at Oak Ridge National Laboratory. Funding for the first upgrade project was initiated in 1996 and all presently identified upgrade projects are expected to be completed by the end of 2003. The upgrade projects include: (1) larger beam tubes, (2) a new monochromator drum for the HB-1 beam line, (3) a new HB-2 beam line system that includes one thermal guide and a new monochromator drum, (4) new instruments for the HB-2 beamline, (5) a new monochromator drum for the HB-3 beam line, (6) a supercritical hydrogen cold source system to be retrofitted into the HB-4 beam tube, (7) a 3.5 kW refrigeration system at 20 K to support the cold source and a new building to house it, (8) a new HB-4 beam line system composed of four cold neutron guides with various mirror coatings and associated shielding, (9) a number of new instruments for the cold beams including two new SANS instruments, and (10) construction of support buildings. This paper provides a short summary of these projects including their present status and schedule.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2015

Acquired experience resulting from transforming a chemical installation into a nuclear one

ICIT-Valcea has developed an experimental pilot-scale installation for tritium and deuterium separation. The main objective of this pilot was to demonstrate the water detritiation technology and to transfer this technology to the CANDU reactors of the Cernavoda nuclear power plant. The pilot-scale installation was initiated in 1992. The initial design and construction were performed similarly to chemical plants as the separation of isotopes was focused on only hydrogen and deuterium to assess feasibility. In a second phase we have begun to transform it into a nuclear facility with the aim of separating tritium. Moving to tritium separation has imposed a lot of changes. Changes consisted mainly of: -) re-design of the technological systems for nuclear material processing, applying specific codes and standards (ASME, Romanian nuclear specific pressure boundary prescriptions for code classification); -) design and implementation of new systems, classified as safety systems; -) re-design and implementation of command and control systems, complying with the requirements of reliability and maintenance required for the project promoted; -) revaluation of auxiliary systems (utilities, power supply); -) implementing radiation protection systems, including secondary barriers; -) implementing and maintaining environment operational program specific to the new nuclear plant; -) developing and conducting safety analyzes; and -) the production of specific documentation to obtain the necessary permits for construction, commissioning and operation of the plant.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗