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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 379 records · Page 21
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Characterization of thin films prepared by co-sputtering iron and titanium precursors and thermal oxidation under air atmosphere

Highlights: • Thin films of mixed iron and titanium oxide were prepared by Ti-Fe annealing. • Segregation and phase separation of iron and titanium oxides are observed. • Formation of iron rich (Fe{sub x}O) nanoparticles at the surface region is revealed. • Formation of thin films with high refractive index can be obtained. - Abstract: Nanocomposites of metal oxides are useful materials for operation in many energy conversion systems. In this study, such nanocomposites were prepared by oxidation of mixtures of iron and titanium precursor metallic thin films at 520 °C under air atmosphere. The metallic films with different iron percentages were obtained by radio frequency (RF) magnetron sputtering on glass and silicon substrates. The films were characterized by means of X-ray Diffraction (XRD), Raman spectroscopy, UV–Vis spectroscopy, High Resolution Scanning Transmission Electron Microscopy (HRSTEM), Ellipsometry and X-ray Photo-electron Spectroscopy (XPS). The results show that these films present mainly two nanometric phases, namely Fe{sub 2}O{sub 3} and TiO{sub 2}. A phase separation was observed; the film surface was found to be iron rich oxide or clusters of iron rich oxide (Fe{sub x}O{sub y}, x > y), whereas titanium accumulated deeply in the bulk, forming TiO{sub 2} far below the film surface. A red shift of optical absorption as well as a relatively stable high refractive index (varying between 3.1 and 3.5) over a broad band of optical frequencies was observed for the films containing higher iron initial concentrations.

36 MATERIALS SCIENCE↗
NASA NTRS1978

Alternative power-generation systems

The present state of the art of thermal power systems is surveyed. Because of the great potential variety of thermal power systems, the heat sources, the power conversion systems, and the integration of thermal power systems with missions are treated sequentially.

English, R. E.↗
NASA NTRS1969

PCS-G systems analysis

Digital computer simulation of SNAP 8 power conversion system G startup and shutdown for systems analysis

Favero, L. R.↗
NASA NTRS1994

Alkali Metal Rankine Cycle Boiler Technology Challenges and Some Potential Solutions for Space Nuclear Power and Propulsion Applications

Alkali metal boilers are of interest for application to future space Rankine cycle power conversion systems. Significant progress on such boilers was accomplished in the 1960's and early 1970's, but development was not continued to operational systems since NASA's plans for future space missions were drastically curtailed in the early 1970's. In particular, piloted Mars missions were indefinitely deferred. With the announcement of the Space Exploration Initiative (SEI) in July 1989 by President Bush, interest was rekindled in challenging space missions and, consequently in space nuclear power and propulsion. Nuclear electric propulsion (NEP) and nuclear thermal propulsion (NTP) were proposed for interplanetary space vehicles, particularly for Mars missions. The potassium Rankine power conversion cycle became of interest to provide electric power for NEP vehicles and for 'dual-mode' NTP vehicles, where the same reactor could be used directly for propulsion and (with an additional coolant loop) for power. Although the boiler is not a major contributor to system mass, it is of critical importance because of its interaction with the rest of the power conversion system; it can cause problems for other components such as excess liquid droplets entering the turbine, thereby reducing its life, or more critically, it can drive instabilities-some severe enough to cause system failure. Funding for the SEI and its associated technology program from 1990 to 1993 was not sufficient to support significant new work on Rankine cycle boilers for space applications. In Fiscal Year 1994, funding for these challenging missions and technologies has again been curtailed, and planning for the future is very uncertain. The purpose of this paper is to review the technologies developed in the 1960's and 1970's in the light of the recent SEI applications. In this way, future Rankine cycle boiler programs may be conducted most efficiently. This report is aimed at evaluating alkali metal boiler technology for space Rankine cycle systems. Research is summarized on the problems of flow stability, liquid carryover, pressure drop and heat transfer, and on potential solutions developed, primarily those developed by the NASA Lewis Research Center in the 1960's and early 1970's.

Stone, James R.↗
DOE OSTI2023

Validation and Verification of TEDS Facility HYBRID Modeling

The HYBRID modeling repository is an in-house developed library of models for selected integrated energy systems (IES) modelling. HYBRID models have been developed since 2015 to describe the physical operation of tightly coupled thermal systems including power generators, thermal transport systems, thermal storage, thermal-to-electric conversion systems, and other thermal applications. Here, validation and verification (V&V) capabilities are demonstrated using the Thermal Energy Distribution System (TEDS) at INL. Building upon prior work, the TEDS model has been updated and verified so that it better represents the installed system configuration and the operating control system. The model control system was changed to allow replication of actual experimental procedures. Experimental operations focusing primarily on thermocline tank performance were devised and performed. Several anomalies were found in the operation data of the experiment facility. V&V activities calibrating a selected input parameter are demonstrated on a single component as well as with a single parameter within the thermocline. Calibrating is then demonstrated on multiple components and a multi-parameter metric for the entire system. The validation methodology is successfully applied to validate the model with experimental data. It is also used to confirm a hypothesis behind one of the anomalies in experimental performance.

25 ENERGY STORAGE↗
DOE OSTI2023

HYBRID Modeling Validation and Verification Status Matrix

The HYBRID modeling repository is a premier resource for integrated energy systems modeling. HYBRID models have been developed since 2015 to describe the physical operation of tightly coupled thermal systems including power generators, thermal transport systems, thermal storage, thermal-to-electric conversion systems, and other thermal applications. Due to the increased size of the repository, a concise summary matrix of available models is desired. This matrix will consolidate not only the list of available models but also indicate original information sources, publications that have model examples, and level of validation and verification that exists for the models. Validation and verification (V&V) levels begin from simplified algebraic relationship and advance to dynamic data validation. Moving forward, as new models are contributed to HYBRID, their V&V level will be included, updating this matrix.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
NASA NTRS1977

Nuclear Science Symposium, 23rd, Scintillation and Semiconductor Counter Symposium, 15th, and Nuclear Power Systems Symposium, 8th, New Orleans, La., October 20-22, 1976, Proceedings

The volume includes papers on semiconductor radiation detectors of various types, components of radiation detection and dosimetric systems, digital and microprocessor equipment in nuclear industry and science, and a wide variety of applications of nuclear radiation detectors. Semiconductor detectors of X-rays, gamma radiation, heavy ions, neutrons, and other nuclear particles, plastic scintillator arrays, drift chambers, spark wire chambers, and radiation dosimeter systems are reported on. Digital and analog conversion systems, digital data and control systems, microprocessors, and their uses in scientific research and nuclear power plants are discussed. Large-area imaging and biomedical nucleonic instrumentation, nuclear power plant safeguards, reactor instrumentation, nuclear power plant instrumentation, space instrumentation, and environmental instrumentation are dealt with. Individual items are announced in this issue.

Wagner, L. J.↗
NASA NTRS1984

SP-100 space nuclear power system

A baseline design concept for a 100 kWe nuclear reactor space power system is described. The concept was developed under contract from JPL as part of a joint program of the DOE, DOD, and NASA. The major technical and safety constraints influencing the selection of reactor operating parameters are discussed. A lithium-cooled compact fast reactor was selected as the best candidate system. The material selected for the thermoelectric conversion system was silicon germanium (SiGe) with gallium phosphide doping. Attention is given to the improved safety of the seven in-core control rod configuration.

Given, R. W.↗
NASA NTRS1976

Nuclear thermionic power system for spacecraft

Mission studies have shown that nuclear electric propulsion is necessary for providing the needed propulsion system for detailed outer planet exploration. The study is centered around thermionic conversion based on an out-of-core approach employing heat pipes to thermally couple the nuclear reactor with the thermionic converters. Emphasis is on a parametric study to size a 500 kWe thermionic power conversion system suitable for a single shuttle launch. It is shown that out-of-core thermionic conversion results in a large L/D system that produces minimum weight. This evolving thermionic technology is compatible with developing insulator technology allowing operation at temperatures compatible with both molybdenum and insulators while retaining a sufficiently high heat rejection temperature to minimize radiator size and weight.

Phillips, W. M.↗
NASA NTRS1980

Cogeneration Technology Alternatives Study (CTAS). Volume 2: Analytical approach

The use of various advanced energy conversion systems were compared with each other and with current technology systems for their savings in fuel energy, costs, and emissions in individual plants and on a national level. The ground rules established by NASA and assumptions made by the General Electric Company in performing this cogeneration technology alternatives study are presented. The analytical methodology employed is described in detail and is illustrated with numerical examples together with a description of the computer program used in calculating over 7000 energy conversion system-industrial process applications. For Vol. 1, see 80N24797.

Gerlaugh, H. E.↗
DOE OSTI2016

Design of a Thermal Energy Storage System for SMR's

A potential deployment strategy for Small Modular Reactors (SMR's) is in hybrid energy systems where the presence of intermittent energy sources (wind and/or solar) subjects the reactor to a time varying electric load (1). Proposed options for accommodating this load have included operating the reactor in a load follow mode, or operating the reactor at or near steady state and bypassing steam around the turbine directly to the condenser (2). Both of these strategies result in lost energy potential. With the large financial investment associated with a nuclear power plant there is strong economic incentive to run the plant at maximum capacity. One method to accomplish this is the installation of Thermal Energy Storage (TES) that can be charged when grid demand is less than 100% plant capacity. The thermal energy can then be recovered, either as a supplement to the power plant during peak demand times, or can be used for other processes (1). Sensible heat thermal energy storage systems have been proposed for solar energy systems (3). This paper describes such a system for SMRs. These results show the feasibility of a TES system alongside a nuclear power plant that can limit load following operations for the reactor. Load following results in a decrease of capacity factor for the plant along with imposing significant stresses to plant equipment. With the implementation of a TES system these stresses can be transferred from the nuclear plant to the TES system. Not only does this equate to a longer overall life of the plant's hardware, but it also will dramatically increase the capacity factor of the system. This increase in capacity factor will lead to an improved economic return over the lifespan of the reactor. Future development in the near term will focus on coupling the TES system to the dynamic response of the reactor and energy conversion system and developing the models necessary to implement the discharge mode. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗