SEARCH · Engineering Papers

Results for “Reactor Design”

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.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 955 records · Page 53

All sources NASA NTRS DOE OSTI

NASA NTRS2013

Kilowatt-Class Fission Power Systems for Science and Human Precursor Missions

Nuclear power provides an enabling capability for NASA missions that might otherwise be constrained by power availability, mission duration, or operational robustness. NASA and the Department of Energy (DOE) are developing fission power technology to serve a wide range of future space uses. Advantages include lower mass, longer life, and greater mission flexibility than competing power system options. Kilowatt-class fission systems, designated "Kilopower," were conceived to address the need for systems to fill the gap above the current 100-Wclass radioisotope power systems being developed for science missions and below the typical 100-kWe-class reactor power systems being developed for human exploration missions. This paper reviews the current fission technology project and examines some Kilopower concepts that could be used to support future science missions or human precursors.

Mason, Lee↗

NASA NTRS1986

1985 Nuclear Science Symposium, 32nd, and 1985 Symposium on Nuclear Power Systems, 17th, San Francisco, CA, October 23-25, 1985, Proceedings

The present conference ranges over topics in high energy physics instrumentation, detectors, nuclear medical applications, health physics and environmental monitoring, reactor instrumentation, nuclear spacecraft instrumentation, the 'Fastbus' data acquisition system, circuits and systems for nuclear research facilities, and the development status of nuclear power systems. Specific attention is given to CCD high precision detectors, a drift chamber preamplifier, a Cerenkov ring imaging detector, novel scintillation glasses and scintillating fibers, a modular multidrift vertex detector, radial wire drift chambers, liquid argon polarimeters, a multianode photomultiplier, the reliability of planar silicon detectors, the design and manufacture of wedge and strip anodes, ultrafast triode photodetectors, photomultiplier tubes, a barium fluoride plastic scintillator, a fine grained neutron hodoscope, the stability of low leakage silicon photodiodes for crystal calorimeters, and X-ray proportional counters. Also considered are positron emission tomography, single photon emission computed tomography, nuclear magnetic resonance imaging, Geiger-Muller detectors, nuclear plant safeguards, a 32-bit Fastbus computer, an advanced light water reactor, and nuclear plant maintenance.

Source record↗

NASA NTRS1983

A parametric study of thermally augmented O2/H2 rocket enines

An analysis is presented of the performance of a conceptual propulsion system in which liquid hydrogen and liquid oxygen are first vaporized and heated by thermal power from a spacecraft nuclear electric power supply prior to combustion in a rocket engine. Calculations of the specific impulse (I-sp) are presented for a series of O2/H2 oxidizer-to-fuel mixture ratios and reactant pre-heat temperatures (T-aug). It is found that the ratio of the augmentation power to the total engine jet power (P-aug/P-tot) determines the engine thrust for a given P-aug, T-aug, and I-sp. In addition, the performance of an unaugmented O2/H2 and a heated-hydrogen rocket engine were also calculated for the same conditions. Results show that an augmented O2/H2 engine has three to eight times the thrust of a heated H2 engine for a given P-aug. It is concluded that it should be possible to design a high/low thrust propulsion system using a common propellant, with the option of using thermal power from the nuclear electric power supply to augment the low-thrust propulsion system during cruise periods when the reactor's full electric power is not needed.

Frisbee, R. H.↗

NASA NTRS2011

A Small Fission Power System for NASA Planetary Science Missions

In March 2010, the Decadal Survey Giant Planets Panel (GPP) requested a short-turnaround study to evaluate the feasibility of a small Fission Power System (FPS) for future unspecified National Aeronautics and Space Administration (NASA) science missions. FPS technology was considered a potential option for power levels that might not be achievable with radioisotope power systems. A study plan was generated and a joint NASA and Department of Energy (DOE) study team was formed. The team developed a set of notional requirements that included 1-kW electrical output, 15-year design life, and 2020 launch availability. After completing a short round of concept screening studies, the team selected a single concept for concentrated study and analysis. The selected concept is a solid block uranium-molybdenum reactor core with heat pipe cooling and distributed thermoelectric power converters directly coupled to aluminum radiator fins. This paper presents the preliminary configuration, mass summary, and proposed development program.

Mason, Lee↗

NASA NTRS2021

Compass Final Report: Nuclear Electric Propulsion (NEP)-Chemical Vehicle 1.2

Many previous studies have examined sending crews to and from Mars. The most economical involved a ‘conjunction’ class whereby the crew spends around 500 days on Mars waiting for a ‘cheap’ return. The total mission time results in over a 1000-day mission duration (about 3 years). Given the current experience level of only one year on the International Space Station (ISS), it of interest to reduce that time to only two years, thus reducing risk and minimizing required Mars surface infrastructure. The Phase 1.1 Study goal was stated as follows, “Determine the feasibility of a two-year roundtrip class Mars mission concept of operation that enables boots on Mars no later than 2036.” While the Phase1 study did show feasibility for the NEP-Chemical option, the 2036 Opposition opportunity was found to stress the schedule due to proposed technology development schedules. A 2039 Opposition (which requires even more energy than the 2036 case) was chosen as representative for Phase 1.2. Phase 1.2 also sought to further refine the concept, building on the feasibility, but addressing several challenges brought by the red team and habitat team. Given the date of 2039, nearer term technologies, primarily nuclear thermal and nuclear electric were deemed as the most viable for these missions. As will be shown, the energy required to perform such a mission in only two years (for the 2039 opportunity at least) is about three times that of the three-year conjunction mission. The rocket equation shows that this mission would then require several times the propellant of the three-year mission unless the specific impulse (ISP) of the propulsion system can be increased. Based on lunar needs, a limit of five Space Launch System (SLS) launchers with 8.4m fairings was imposed for the piloted transportation portion of the mission, limiting the size of the system. When using nuclear electric propulsion, the main limiting factor was packaging the required radiator area. The higher Isp nuclear electric propulsion (NEP) system option is described herein but with a twist: in order to keep the size of radiators packageable in one SLS and use proven reactor power system technology (~1200K reactor outlet temperature and superalloy-class Brayton) the NEP system had to be combined with a chemical propulsion system. This combination of electric propulsion and high thrust chemical was found to be useful in previous design studies combining solar electric propulsion (SEP) and chemical propulsion. Such a combination allowed the low-thrust system to provide significant change in velocity (∆V) during the interplanetary portions of the mission, thereby notably reducing the ∆V required by the high thrust system to capture and depart from the Mars gravity well. Here the high thrust ‘impulsive’ system is more efficient due to the Oberth Effect. A plethora of trades, both at the mission and system level, as well as the subsystem level were performed to develop these vehicle concepts. An entire family of NEP-Chemical transportation vehicles is described herein. The main driver and the primary focus was the piloted vehicle but additional concepts for cargo were performed using the same ‘building blocks’ in order to reduce costs and provide commonality.

Nuclear Power↗

NASA NTRS1999

Evaluation of the Hydrodynamic Focusing Bioreactor (HDFB) and the Centrifugal Absorption Cartridge System (CACS) Performance Under Micro G

The Hydrodynamic Focusing Bioreactor (HDFB) technology is designed to provide a flow field with nearly uniform shear force throughout the vessel, which can provide the desired low shear force spatial environment to suspend three-dimensional cell aggregates while providing optimum mass transfer. The reactor vessel consists of a dome-shaped cell culture vessel, a viscous spinner, an access port, and a rotating base. The domed vessel face has a radius of R(o). and rotates at 0mega(o) rpm, while the internal viscous spinner has a radius of R(i) and rotates at 0mega(i) rpm. The culture vessel is completely filled with cell culture medium into which three-dimensional cellular structures are introduced. The HDFB domed vessel and spinner were driven by two independent step motors,

Gonda, Steve↗

NASA NTRS2007

NTREES Testing and Operations Status

Nuclear Thermal Rockets or NTR's have been suggested as a propulsion system option for vehicles traveling to the moon or Mars. These engines are capable of providing high thrust at specific impulses at least twice that of today's best chemical engines. The performance constraints on these engines are mainly the result of temperature limitations on the fuel coupled with a limited ability to withstand chemical attack by the hot hydrogen propellant. To operate at maximum efficiency, fuel forms are desired which can withstand the extremely hot, hostile environment characteristic of NTR operation for at least several hours. The simulation of such an environment would require an experimental device which could simultaneously approximate the power, flow, and temperature conditions which a nuclear fuel element (or partial element) would encounter during NTR operation. Such a simulation would allow detailed studies of the fuel behavior and hydrogen flow characteristics under reactor like conditions to be performed. Currently, the construction of such a simulator has been completed at the Marshall Space Flight Center, and will be used in the future to evaluate a wide variety of fuel element designs and the materials of which they are fabricated. This present work addresses the operational status of the Nuclear Thermal Rocket Element Environmental Simulator or NTREES and some of the design considerations which were considered prior to and during its construction.

Emrich, Bill↗

NASA NTRS2014

An Alternative Water Processor for Long Duration Space Missions

A new wastewater recovery system has been developed that combines novel biological and physicochemical components for recycling wastewater on long duration human space missions. Functionally, this Alternative Water Processor (AWP) would replace the Urine Processing Assembly on the International Space Station and reduce or eliminate the need for the multi-filtration beds of the Water Processing Assembly (WPA). At its center are two unique game changing technologies: 1) a biological water processor (BWP) to mineralize organic forms of carbon and nitrogen and 2) an advanced membrane processor (Forward Osmosis Secondary Treatment) for removal of solids and inorganic ions. The AWP is designed for recycling larger quantities of wastewater from multiple sources expected during future exploration missions, including urine, hygiene (hand wash, shower, oral and shave) and laundry. The BWP utilizes a single-stage membrane-aerated biological reactor for simultaneous nitrification and denitrification. The Forward Osmosis Secondary Treatment (FOST) system uses a combination of forward osmosis (FO) and reverse osmosis (RO), is resistant to biofouling and can easily tolerate wastewaters high in non-volatile organics and solids associated with shower and/or hand washing. The BWP has been operated continuously for over 300 days. After startup, the mature biological system averaged 85% organic carbon removal and 44% nitrogen removal, close to stoichiometric maximum based on available carbon. To date, the FOST has averaged 93% water recovery, with a maximum of 98%. If the wastewater is slighty acidified, ammonia rejection is optimal. This paper will provide a description of the technology and summarize results from ground-based testing using real wastewater

Barta, Daniel J.↗

NASA NTRS2015

A Biologically-Based Alternative Water Processor for Long Duration Space Missions

A wastewater recovery system has been developed that combines novel biological and physicochemical components for recycling wastewater on long duration space missions. Functionally, this Alternative Water Processor (AWP) would replace the Urine Processing Assembly on the International Space Station and reduce or eliminate the need for the multifiltration beds of the Water Processing Assembly (WPA). At its center are two unique game changing technologies: 1) a biological water processor (BWP) to mineralize organic forms of carbon and nitrogen and 2) an advanced membrane processor (Forward Osmosis Secondary Treatment) for removal of solids and inorganic ions. The AWP is designed for recycling larger quantities of wastewater from multiple sources expected during future exploration missions, including urine, hygiene (hand wash, shower, oral and shave) and laundry. The BWP utilizes a single-stage membrane-aerated biological reactor for simultaneous nitrification and denitrification. The Forward Osmosis Secondary Treatment (FOST) system uses a combination of forward osmosis (FO) and reverse osmosis (RO), is resistant to biofouling and can easily tolerate wastewaters high in non-volatile organics and solids associated with shower and/or hand washing. The BWP was operated continuously for over 300 days. After startup, the mature biological system averaged 85% organic carbon removal and 44% nitrogen removal, close to maximum based on available carbon. The FOST has averaged 93% water recovery, with a maximum of 98%. If the wastewater is slighty acidified, ammonia rejection is optimal. This paper will provide a description of the technology and summarize results from ground-based testing using real wastewater.

Barta, Daniel J.↗

NASA NTRS2020

Development of a Photosynthesis Measurement Chamber under Different Airspeeds for Applications in Future Space Crop-Production Facilities

Space crop production systems are being developed to grow fresh produce in-situ to supplement the astronauts’ diet, but the required ventilation rates for crops in different gravity environments remains poorly understood. The reduction or lack of buoyancy-driven convection in reduced gravity environments leads to impaired gas exchange (CO2 absorption, water transpiration and O2 release) at the leaf surface if no extra ventilation is provided, and this could lead to a reduction in biomass production in the long run. To better characterize the influence of different airspeeds on photosynthesis and be able to model this in low gravity, a chamber was designed to interface with a LI-6800 portable photosynthesis system. This paper details the design of this chamber, specifically made to measure whole-plant and small canopy gas exchange at different airspeeds. The fans provide turbulent mixing in the chamber to ensure that it behaves like a continuous stirred tank reactor (CSTR)and that the residence time distribution (RTD) is the same for any fan speed; the computational fluid dynamic (CFD) model of the gas domain (the air in the chamber) hence uses a k-omega turbulence model. An airflow map of the chamber was created using anemometer measurements for the different airspeeds tested, and this was used together with the CFD simulation results to relate the experimentally measured fan outputs to actual airspeeds on top of an artificial plant. Environmental parameters (air temperature, relative humidity, CO2level) are controlled by the LI-6800. This work was funded by NASA Space Biology through the NASA postdoctoral program / USRA.

Lucie Poulet↗

NASA NTRS1991

Rotating reactor studies

Undesired gravitational effects such as convection or sedimentation in a fluid can sometimes be avoided or decreased by the use of a closed chamber uniformly rotated about a horizontal axis. In a previous study, the spiral orbits of a heavy or buoyant particle in a uniformly rotating fluid were determined. The particles move in circles, and spiral in or out under the combined effects of the centrifugal force and centrifugal buoyancy. A optimization problem for the rotation rate of a cylindrical reactor rotated about its axis and containing distributed particles was formulated and solved. Related studies in several areas are addressed. A computer program based on the analysis was upgraded by correcting some minor errors, adding a sophisticated screen-and-printer graphics capability and other output options, and by improving the automation. The design, performance, and analysis of a series of experiments with monodisperse polystyrene latex microspheres in water were supported to test the theory and its limitations. The theory was amply confirmed at high rotation rates. However, at low rotation rates (1 rpm or less) the assumption of uniform solid-body rotation of the fluid became invalid, and there were increasingly strong secondary motions driven by variations in the mean fluid density due to variations in the particle concentration. In these tests the increase in the mean fluid density due to the particles was of order 0.015 percent. To a first approximation, these flows are driven by the buoyancy in a thin crescent-shaped depleted layer on the descending side of the rotating reactor. This buoyancy distribution is balanced by viscosity near the walls, and by the Coriolis force in the interior. A full analysis is beyond the scope of this study. Secondary flows are likely to be stronger for buoyant particles, which spiral in towards the neutral point near the rotation axis under the influence of their centrifugal buoyancy. This is because the depleted layer is thicker and extends all the way around the reactor.

Roberts, Glyn O.↗

NASA NTRS1975

SUMMA hot-ion plasma heating research at NASA Lewis Research Center

This report describes the SUMMA superconducting magnetic mirror facility at the NASA Lewis Research Center and the hot-ion plasma research conducted therein. SUMMA is characterized by intense magnetic fields (designed for 8.6 T at the mirrors) and a large-diameter working bore (41 cm diameter) with room-temperature access. The goal of the plasma research program is to produce steady-state plasmas of fusion reactor densities and temperatures (but not confinement times). The program includes electrode development to produce a hot, dense, large-volume, steady-state plasma and diagnostics development to document the plasma properties. SUMMA and its hot-ion plasma are ideally suited to develop advanced plasma diagnostics methods. Two such methods whose requirements are well matched to SUMMA are: (1) heavy ion beam probing to measure plasma space potential, and (2) submillimeter wavelength laser Thomson scattering to measure local ion temperature. Two NASA University Grants were established to identify major requirements for developing these two diagnostic techniques in SUMMA.

Reinmann, J. J.↗

NASA NTRS1985

Tethered nuclear power for the Space Station

A nuclear space power system the SP-100 is being developed for future missions where large amounts of electrical power will be required. Although it is primarily intended for unmanned spacecraft, it can be adapted to a manned space platform by tethering it above the station through an electrical transmission line which isolates the reactor far away from the inhabited platform and conveys its power back to where it is needed. The transmission line, used in conjunction with an instrument rate shield, attenuates reactor radiation in the vicinity of the space station to less than one-one hundredth of the natural background which is already there. This combination of shielding and distance attenuation is less than one-tenth the mass of boom-mounted or onboard man-rated shields that are required when the reactor is mounted nearby. This paper describes how connection is made to the platform (configuration, operational requirements) and introduces a new element the coaxial transmission tube which enables efficient transmission of electrical power through long tethers in space. Design methodology for transmission tubes and tube arrays is discussed. An example conceptual design is presented that shows SP-100 at three power levels 100 kWe, 300 kWe, and 1000 kWe connected to space station via a 2 km HVDC transmission line/tether. Power system performance, mass, and radiation hazard are estimated with impacts on space station architecture and operation.

Bents, D. J.↗

NASA NTRS1986

Modeling of transient heat pipe operation

Mathematical models and associated solution procedures which can be used to design heat pipe cooled structures for use on hypersonic vehicles are being developed. The models should also have the capability to predict off-design performance for a variety of operating conditions. It is expected that the resulting models can be used to predict startup behavior of liquid metal heat pipes to be used in reentry vehicles, hypersonic aircraft, and space nuclear reactors. Work to date related to numerical solutions of governing differential equations for the outer shell and the combination capillary structure and working fluid is summarized. Finite element numerical equations using both implicit, explicit, and combination methods were examined.

Colwell, G. T.↗

NASA NTRS1985

Tethered nuclear power for the space station

Bents, D. J.↗

NASA NTRS2013

Kilowatt-Class Fission Power Systems for Science and Human Precursor Missions

Nuclear power provides an enabling capability for NASA missions that might otherwise be constrained by power availability, mission duration, or operational robustness. NASA and the Department of Energy (DOE) are developing fission power technology to serve a wide range of future space uses. Advantages include lower mass, longer life, and greater mission flexibility than competing power system options. Kilowatt-class fission systems, designated "Kilopower," were conceived to address the need for systems to fill the gap above the current 100-W-class radioisotope power systems being developed for science missions and below the typical 100-k We-class reactor power systems being developed for human exploration missions. This paper reviews the current fission technology project and examines some Kilopower concepts that could be used to support future science missions or human precursors.

Flexibility↗

NASA NTRS2019

Thermal, Fluid and Neutronic Analysis of an LEU Nuclear Thermal Propulsion Core

This paper describes the use of detailed multidisciplinary fluid/thermal/ structural/neutronic simulations to predict performance of the nuclear fuel elements of a Nuclear Thermal Propulsion rocket reactor. To achieve maximum performance, a rocket reactor's fuel must operate near thermal hydraulic, structural and neutronic limits where multidisciplinary interactions are important. Yet physical testing is expensive, time- consuming and risky. Lower-fidelity correlations (heat transfer) and simulations have always existed for design, and one role of detailed numerical analysis is to confirm correlation validity and accuracy. For complex and subtle issues, detailed numerical simulations may prove their value. The paper gives examples of both of these situations. Limitations of the methods and potential extensions will be explored.

Rocket Engine Design↗

NASA NTRS1983

Energetic closed-cycle gas core reactors for orbit raising

Closed-cycle gas core reactor power plants can be of two types. In the 'mixed flow' type, the gaseous nuclear fuel is intimately mixed with the working gas in the cavity. In the 'light bulb' type the fissioning plasma is enclosed in a transparent tube, and energy transfer to the separate working gas occurs by thermal radiation. The potentials of high temperature gas core reactors in terrestrial electric power generator applications have been considered, and a number of civilian power-beaming applications for gaseous fuel nuclear-MHD power plants in space have been suggested. Major conclusions of investigations related to the design of space power systems are discussed. Attention is given to options for conversion cycles, the power system specific mass, and research and technology issues.

Rosa, R. J.↗