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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Knudsen Effusion Mass Spectrometry: Principles and Applications

Knudsen Effusion Mass Spectrometry (KEMS) is a well-established technique in physical chemistry. First, we discuss the basic principles of the technique. It is based on a small enclosure which sets up a condensed/vapor near equilibria. A small, well-defined orifice allows the vapor to be sampled a mass spectrometer. Although the number of groups utilizing this method has decrease significantly from its height in 1960s, we will show that it is still useful for many problems in physical chemistry, materials science, geology, and nuclear science. Specific examples illustrate its versatility: Measurement of the enthalpy of formation of HfO(g); measurement of activities in the Ti-Al-O and Ni-Al systems; measurement of activities in several rare earth silicate systems; measurement of vapor pressures above olivine; dating of minerals with K/Ar method; and determination of adsorption/desorption behavior on nuclear fission products on graphite. These are only a small sampling of the many applications of this versatile technique.

Mass spectrometry, thermodynamics, high temperatur↗
NASA NTRS2011

Non-Nuclear Testing of Fission Technologies at NASA MSFC

Highly realistic non-nuclear testing can be used to investigate and resolve potential issues with space nuclear power and propulsion systems. Non-nuclear testing is particularly useful for systems designed with fuels and materials operating within their demonstrated nuclear performance envelope. Non-nuclear testing also provides an excellent way for screening potential advanced fuels and materials prior to nuclear testing, and for investigating innovative geometries and operating regimes. Non-nuclear testing allows thermal hydraulic, heat transfer, structural, integration, safety, operational, performance, and other potential issues to be investigated and resolved with a greater degree of flexibility and at reduced cost and schedule compared to nuclear testing. The primary limit of non-nuclear testing is that nuclear characteristics and potential nuclear issues cannot be directly investigated. However, non-nuclear testing can be used to augment the potential benefit from any nuclear testing that may be required for space nuclear system design and development. This paper describes previous and ongoing non-nuclear testing related to space nuclear systems at NASA s Marshall Space Flight Center (MSFC).

Houts, Robert G.↗
NASA NTRS1999

Results of a First Generation Propellant Energy Source Module Testing: Non-Nuclear Testing of Fission System

The use of resistance heaters to simulate heat from fission allows extensive development of fission systems to be performed in non-nuclear test facilities, saving time and money. Resistance heated tests on the Module Unfueled Thermal- hydraulic Test (MUTT) article has been performed at the Marshall Space Flight Center. This paper discusses the results of these experiments to date, and describes the additional testing that will be performed. Recommendations related to the design of testable space fission power and propulsion systems are made.

VanDyke, Melissa↗
NASA NTRSDate not supplied

Nuclear Thermal Propulsion (NTP) Fission Product and Source Term Analysis

Nuclear thermal propulsion (NTP) is an in-space propulsion technology that uses a nuclear reactor to directly heat a propellant to provide high thrust, at higher efficiencies than achievable with conventional chemical propulsion systems. Due to the ability of NTP rockets to efficiently provide high thrust, this technology has been proposed for long duration space missions such as crewed missions to Mars and beyond. A primary hurdle for NTP technology development is the demonstration of an integrated reactor engine system to verify its functionality and performance. This primarily requires the manufacture and testing of candidate reactor and engine technologies to demonstrate the proposed design enables desired performance and exhibits acceptable response under all known operation modes. A major component in this testing is fission product accumulation, since after operation radioactive isotopes can be produced and pose radiological dose concerns. This paper explains the background behind fission product analysis and the methodology used to evaluate current reactor designs and identify the amount of fission products present and their radiological impact. Results of multiple thrust level engines at different time periods are discussed and highlight the need for additional experimental testing to confirm fractional release levels of fission products out of the system. Benchmarking of models and future paths of analysis are also discussed.

Fission↗
NASA NTRSDate not supplied

Nuclear Thermal Propulsion (NTP) Fission Product and Source Term Analysis

Nuclear thermal propulsion (NTP) is an in-space propulsion technology that uses a nuclear reactor to directly heat a propellant to provide high thrust, at higher efficiencies than achievable with conventional chemical propulsion systems. Due to the ability of NTP rockets to efficiently provide high thrust, this technology has been proposed for long duration space missions such as crewed missions to Mars and beyond. A primary hurdle for NTP technology development is the demonstration of an integrated reactor engine system to verify its functionality and performance. This primarily requires the manufacture and testing of candidate reactor and engine technologies to demonstrate the proposed design enables desired performance and exhibits acceptable response under all known operation modes. A major component in this testing is fission product accumulation, since after operation radioactive isotopes can be produced and pose radiological dose concerns. This paper explains the background behind fission product analysis and the methodology used to evaluate current reactor designs and identify the amount of fission products present and their radiological impact. Results of multiple thrust level engines at different time periods are discussed and highlight the need for additional experimental testing to confirm fractional release levels of fission products out of the system. Benchmarking of models and future paths of analysis are also discussed.

Nuclear Thermal Propulsion↗
NASA NTRS1963

OUTLOOK FOR GAS-CORE NUCLEAR ROCKETS

Fission energy transferal, hydrogen propellant flow, and adequate fissionable material are main factors in gas-core nuclear rocket design concepts

GASEOUS FISSION REACTOR↗
NASA NTRS1990

Linear energy transfer (LET) spectra of cosmic radiation in low Earth orbit

Integral linear energy transfer (LET) spectra of cosmic radiation (CR) particles were measured on five Cosmos series spacecraft in low Earth orbit (LEO). Particular emphasis is placed on results of the Cosmos 1887 biosatellite which carried a set of joint U.S.S.R.-U.S.A. radiation experiments involving passive detectors that included thermoluminescent detectors (TLDs), plastic nuclear track detectors (PNTDs), fission foils, nuclear photo-emulsions, etc. which were located both inside and outside the spacecraft. Measured LET spectra are compared with those theoretically calculated. Results show that there is some dependence of LET spectra on orbital parameters. The results are used to estimate the CR quality factor (QF) for the Cosmos 1887 mission.

NASA Discipline Radiation Health↗
NASA NTRS2003

The Case of Nuclear Propulsion

Fission technology can enable rapid, affordable access to any point in the solar system. If fission propulsion systems are to be developed to their full potential; however, near-term customers must be identified and initial fission systems successfully developed, launched, and utilized. Successful utilization will simultaneously develop the infrastructure and experience necessary for developing even higher power and performance systems. To be successful, development programs must devise strategies for rapidly converting paper reactor concepts into actual flight hardware. One approach to accomplishing this is to design highly testable systems, and to structure the program to contain frequent, significant hardware milestones. This paper discusses ongoing efforts in Russia and the United States aimed at enabling near-term utilization of space fission systems.

Koroteev, Anatoly S.↗
NASA NTRSDate not supplied

Space Nuclear Propulsion 101

The Fission Surface Power (FSP) project is a NASA effort to demonstrate a tens of kilowatt class nuclear fission reactor power system on the Moon in next decade. Fission technology promises a class of long-duration Sun-independent scalable power systems with applications across the Solar System. The FSP project is just the beginning of the journey for this technology. This presentation will showcase the current state of the project, technical goals and accomplishments, future plans, and how this technology may find exciting future applications.

fission↗
NASA NTRS1995

Linear Energy Transfer (LET) spectra of cosmic radiation in low Earth orbit

Integral linear energy transfer (LET) spectra of cosmic radiation (CR) particles were measured on five Cosmos series spacecraft in low Earth orbit (LEO). Particular emphasis is placed on results of the Cosmos 1887 biosatellite which carried a set of joint U.S.S.R.-U.S.A. radiation experiments involving passive detectors that included thermoluminescent detectors (TLD's), plastic nuclear track detectors (PNTD's), fission foils, nuclear photo-emulsions, etc. which were located both inside and outside the spacecraft. Measured LET spectra are compared with those theoretically calculated. Results show that there is some dependence of LET spectra on orbital parameters. The results are used to estimate the CR quality factor (QF) for the COSMOS 1887 mission.

Parnell, T. A.↗
NASA NTRS2013

Reactor Simulator Testing

As part of the Nuclear Systems Office Fission Surface Power Technology Demonstration Unit (TDU) project, a reactor simulator test loop (RxSim) was design & built to perform integrated testing of the TDU components. In particular, the objectives of RxSim testing was to verify the operation of the core simulator, the instrumentation and control system, and the ground support gas and vacuum test equipment. In addition, it was decided to include a thermal test of a cold trap purification design and a pump performance test at pump voltages up to 150 V since the targeted mass flow rate of 1.75 kg/s was not obtained in the RxSim at the originally constrained voltage of 120 V. This paper summarizes RxSim testing. The gas and vacuum ground support test equipment performed effectively in NaK fill, loop pressurization, and NaK drain operations. The instrumentation and control system effectively controlled loop temperature and flow rates or pump voltage to targeted settings. The cold trap design was able to obtain the targeted cold temperature of 480 K. An outlet temperature of 636 K was obtained which was lower than the predicted 750 K but 156 K higher than the cold temperature indicating the design provided some heat regeneration. The annular linear induction pump (ALIP) tested was able to produce a maximum flow rate of 1.53 kg/s at 800 K when operated at 150 V and 53 Hz. Keywords: fission, space power, nuclear, liquid metal, NaK.

Schoenfeld, Michael P.↗
NASA NTRS2016

Nonproliferation Challenges in Space Defense Technology - PANEL

The use of highly enriched uranium (HEU) almost always "helps" space fission systems. Nuclear Thermal Propulsion (NTP) and high power fission electric systems appear able to use < 20% enriched uranium with minimal / acceptable performance impacts. However, lower power, "entry level" systems may be needed for space fission technology to be developed and utilized. Low power (i.e. approx.1 kWe) fission systems may have an unacceptable performance penalty if LEU is used instead of HEU. Are there Ways to Support Non-Proliferation Objectives While Simultaneously Helping Enable the Development and Utilization of Modern Space Fission Power and Propulsion Systems?

Nuclear↗
NASA NTRS2021

Operational Considerations for Fission Reactors Utilized on Nuclear Thermal Propulsion Missions to Mars

This report is aimed at identifying the implications associated with the operation of space nuclear power reactors that would be utilized for Nuclear Thermal Propulsion (NTP) missions to Mars. The objective of this study is to evaluate the operational features of reactors that could provide propulsion and possibly electrical power for future crewed and cargo missions to Mars. This report follows upon an initial report looking at the generic considerations for operating fission reactors in space applications and is intended as a deeper dive into the operational features related to specific Mars NTP applications.

Nuclear Thermal Propulsion↗
NASA NTRS1975

Fissioning uranium plasmas and nuclear-pumped lasers

Current research into uranium plasmas, gaseous-core (cavity) reactors, and nuclear-pumped lasers is discussed. Basic properties of fissioning uranium plasmas are summarized together with potential space and terrestrial applications of gaseous-core reactors and nuclear-pumped lasers. Conditions for criticality of a uranium plasma are outlined, and it is shown that the nonequilibrium state and the optical thinness of a fissioning plasma can be exploited for the direct conversion of fission fragment energy into coherent light (i.e., for nuclear-pumped lasers). Successful demonstrations of nuclear-pumped lasers are described together with gaseous-fuel reactor experiments using uranium hexafluoride.

Schneider, R. T.↗
NASA NTRS1974

Research on fission fragment excitation of gases and nuclear pumping of lasers

Experimental investigations of fission fragment excited gases are reported along with a theoretical analysis of population inversions in fission fragment excited helium. Other studies reported include: nuclear augmentation of gas lasers, direct nuclear pumping of a helium-xenon laser, measurements of a repetitively pulsed high-power CO2 laser, thermodynamic properties of UF6 and UF6/He mixtures, and nuclear waste disposal utilizing a gaseous core reactor.

Schneider, R. T.↗
NASA NTRS2015

NASA's Nuclear Thermal Propulsion Project

Space fission power systems can provide a power rich environment anywhere in the solar system, independent of available sunlight. Space fission propulsion offers the potential for enabling rapid, affordable access to any point in the solar system. One type of space fission propulsion is Nuclear Thermal Propulsion (NTP). NTP systems operate by using a fission reactor to heat hydrogen to very high temperature (>2500 K) and expanding the hot hydrogen through a supersonic nozzle. First generation NTP systems are designed to have an Isp of approximately 900 s. The high Isp of NTP enables rapid crew transfer to destinations such as Mars, and can also help reduce mission cost, improve logistics (fewer launches), and provide other benefits. However, for NTP systems to be utilized they must be affordable and viable to develop. NASA's Advanced Exploration Systems (AES) NTP project is a technology development project that will help assess the affordability and viability of NTP. Early work has included fabrication of representative graphite composite fuel element segments, coating of representative graphite composite fuel element segments, fabrication of representative cermet fuel element segments, and testing of fuel element segments in the Compact Fuel Element Environmental Tester (CFEET). Near-term activities will include testing approximately 16" fuel element segments in the Nuclear Thermal Rocket Element Environmental Simulator (NTREES), and ongoing research into improving fuel microstructure and coatings. In addition to recapturing fuels technology, affordable development, qualification, and utilization strategies must be devised. Options such as using low-enriched uranium (LEU) instead of highly-enriched uranium (HEU) are being assessed, although that option requires development of a key technology before it can be applied to NTP in the thrust range of interest. Ground test facilities will be required, especially if NTP is to be used in conjunction with high value or crewed missions. There are potential options for either modifying existing facilities or constructing new ground test facilities. At least three potential options exist for reducing (or eliminating) the release of radioactivity into the environment during ground testing. These include fully containing the NTP exhaust during the ground test, scrubbing the exhaust, or utilizing an existing borehole at the Nevada National Security Site (NNSS) to filter the exhaust. Finally, the project is considering the potential for an early flight demonstration of an engine very similar to one that could be used to support human Mars or other ambitious missions. The flight demonstration could be an important step towards the eventual utilization of NTP.

Houts, Michael↗