Space Nuclear Power Research Articles

Fallout from Nuclear Power in Space

Fallout from Nuclear Power in Space

Stanford Patent Claim Is Put Under Wraps

Stanford Patent Claim Is Put Under Wraps

Gaseous-Fuel Reactor Systems for Aerospace Applications

Research on the gaseous fuel nuclear rocket concept continues under the programs of the U.S. National Aeronautics and Space Administration (NASA) Office for Aeronautics and Space Technology and now includes work related to power applications in space and on earth. In a cavity reactor test series, initial experiments confirmed the low critical mass determined from reactor physics calculations. Recent work with flowing UF6 fuel indicates stable operation at increased power levels. Preliminary design and experimental verification of test hardware for high-temperature experiments have been accomplished. Research on energy extraction from fissioning gases has resulted in lasers energized by fission fragments. Combined experimental results and studies indicate that gaseous-fuel reactor systems have significant potential for providing nuclear fission power in space and on earth.

Brittle Grain Boundary Fracture in Iridium

Iridium is a most interesting fee metal with a high melting point (2443°C) and extremely high elastic moduli (Young's modulus of 76 million psi). Single crystals of Ir fail by brittle cleavage and polycrystalline Ir fails by brittle intergranular fracture at temperatures below 1000°C. We have previously shown that both modes of fracture are intrinsic and not impurity related. (1)The present study was undertaken to study the grain boundary structure of Ir by transmission electron microscopy. Sheet specimens of Ir-0.3%W (used in space nuclear power applications) were recrystallized at temperatures above 1300°C. Thin foils were prepared by spark planing and electropolishing with an acidified CaCl2 solution in a jet polisher and were examined in a JEOL 200 B electron microscope operated at 200 kv.We examined a large number of foils and found the most interesting grain boundary features to be ledges (2) (Fig. la).

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Vacuum System for Irradiation Studies

An oil-free vacuum system capable of achieving vacuum levels of 10−6 Torr for in-pile experiments has been constructed at the pool-type Battelle Research Reactor (BRR). The pumping system which is mounted on a moveable bridge above the pool surface, consists of a 7500 liter/sec titanium sublimation pump and two 350-liter/sec triode-type ion pumps; system roughing is accomplished with a roots-type blower with a double-walled liquid nitrogen trap. Nine meters of 20.3-cm (8-in.) diam vacuum piping connect the pumping system to a test chamber at the core level. Test chamber geometry can be varied to fit either a 7.62×7.62-cm test cell or the core face. Neutron fluxes of 2×1013 neutron/cm2⋅sec (thermal) and 1×1013 neutron/cm2⋅sec (fast) are available and the maximum gamma rate is 108 R/h. Adjustments of desired gamma/neutron ratio are made by employing appropriate shielding at the core face. Irradiation effects on the performance of electro-mechanical components for space nuclear power systems have been studied at elevated temperatures (620–820 K) and a full-scale nuclear fueled thermionic diode is currently being prepared for irradiation in the system.

Heat-rejection radiator mass and its influence in space power systems

The influence of radiators on space nuclear power system mass has been studied by determining this mass as a function of the parameter K R = radiator mass/ area. Four power-conversion schemes are considered: Brayton, Rankine, thermoelectric and thermionic, over the power range 200–1000 kW. The total system includes power processing equipment and the secondary radiator. The Brayton cycle becomes competitively light (improvements by factors up to 5), and the power range of interest for thermoelectric systems increases significantly with achievable values of K R . The power processor, secondary radiator and shield render present thermionic systems massive, so that other concepts promise lower mass if K R can be reduced to less than 0.5 kg/m 2.

A Nuclear Thermionic Space Power Concept Using Rod Control and Heat Pipes

Nuclear reactor space power system concept using thermionic diodes, heat pipes and rod control, emphasizing neutronic aspects and feasibility

Compatibility of Materials with Alkali Metals for Space Nuclear Power Systems

Compatibility of Materials with Alkali Metals for Space Nuclear Power Systems

SNAP 10A Data Reduction

On April 3, 1965 the world's first nuclear reactor space power system, SNAP I0A, was launched and operated successfully for forty-three days in orbit. To reduce and analyze the flight test data, data handling procedures and data analysis computer programs representing the end results of three years of effort and improvement of similar data systems for SNAP 10A ground tests were used. This paper describes the evolution of data handling and reduction from the manual methods used for the first non-nuclear system test to later ground tests where data loggers of increasing degrees of sophistication were used to generate punched paper tape which was then computer processed, reduced, and analyzed, and finally to the completely electronic and computerized reduction of flight test telemetry data. The equipment used, handling procedures developed, and computer programs are briefly described. Improvements in each generation of data system resulting from experience and improved equipment are emphasized. As a result of the experience in semi-automatic data collection, reduction, and analysis gained in the SNAP 10A program recommendations for creation and improvement of similar data systems are given, and some of the more important pitfalls encountered are discussed. Finally, the more significant differences between flight and ground acquisition and reduction are noted.

Design, ground test and flight test of SNAP 10A, first reactor in space

The first nuclear reactor space power system, SNAP 10A, was successfully flight tested in April 1965. This paper includes a description of the reactor-thermoelectric system and the development program that preceded the flight. Special emphasis is given to the endurance test experience gained from the nuclear ground test system. The flight test is described in detail and the knowledge gained from the test is given.

Snap 10A Flight Test Instrumentation Performance

The instrumentation on SNAP 10A, the world's first nuclear reactor space power system, was evaluated. Flight test information requirements, based on SNAPSHOT test experience, were summarized to provide criteria for judging instrument performance. Generally performance and reliability were good, but as with any initial flight test, instrumentation selected early in the program was not always optimum. These exceptions are emphasized. Larger flight test data errors caused changes in the relative usefulness of different types of instruments in flight compared to ground tests.

SNAPSHOT Launch Operations

SNAP 10A, the first space nuclear reactor power system, was launched and brought to full power on April 3, 1965. The unit consists of a compact reactor, cooled by a liquid metal and coupled to a thermoelectric conversion system. The reactor uses a fully enriched uranium-zirconium hydride material as the combined fuelmoderator and beryllium as the reflector. The demonstration of one primary SNAPSHOT objective - verifying the safe and routine, transport, test and launch of a nuclear system, culminated in the launch at Vandenberg Air Force Base. Launch preparations began with the establishment of generalized procedures for the factory-to-flight sequence. A safety analysis followed, resulting in development of safety devices, administrative controls and emergency procedures. Training of the crew and the validation of the support equipment was accomplished by handling and testing usage in the operations at Atomics International. Further training, procedure verification and equipment validation was obtained by a trial shipment and by sending a test system through the operations sequence. SNAP 10A arrived at VAFB on February 16. After a brief reassembly and checkout period, it was transported to the launch pad. A double pad cycle was instigated to ensure safe and complete checkout. In the first cycle, the system mated to the Agena was subjected to a SNAP 10A-Agenalaunch complex compatibility test. A simulated flight test followed, wherein a complete launch through orbital startup sequence using the backup systems was checked. A second simulated flight test exercised the primary systems.

Nuclear Propulsion and Power in Space

Nuclear Energy in Space By Erik S. Pedersen. (Prentice–Hall Space Technology Series.) Pp. xi + 516. (Englewood Cliffs, N.J., and London: Prentice–Hall, 1964.) 160s.

Grinding the Refractory Metals

A BRIGHT future has been predicted for the refractory metals for aerospace applications. Typical uses include; solid propellent rocket motor nozzles, re‐entry surfaces for gliders and nuclear space power systems (liquid metal containers). Refractory metals are already employed on ram jet engines, hot structure sections capable of supporting aerodynamic and thermal stresses, or as heat shields protecting low temperature structural members.

CONTROL OF BERYLLIUM FIRE HAZARDS IN A FIRE TEST SERIES.

Abstract As part of the SNAP-10A (Space Nuclear Auxiliary Power) project, beryllium hazards were measured in four controlled fires. Over 125 air samples and swipe samples were taken during the tests; only eight samples showed concentrations of Be above the minimum detectable level. Controls and procedures described insured safe test conditions. Areas needing further study are noted.

Vapor Cycle Coolant Requirements for Nuclear Space Power Plants

This paper includes a discussion of choice of coolants in the design of nuclear space power plants. Among the specific problems discussed are loss of coolant through meteoroid penetration, compatibility between coolant and construction materials at high temperatures, probability of damage by meteoroids and fabrication problems associated with large, lightweight, hermetically sealed structures which must be packageable, assembled in space and launched into orbit.

Reliability Limitations on Electronics for Nuclear Propulsion and Space Power Systems

Although a large amount of data is available on the temperature and radiation effects on electronic components, it does not contain the necessary engineering information that can be found for the more conventional space electronics design. For nuclear applications, the electronics designer needs information on a much greater number of components because of the wide range of temperature and radiation environments. A coordinated development and reliability program should be started now to assure the usefulness of nuclear propulsion and space power by providing the necessary reliable components and the engineering design information required to design the electronic equipment.