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Low work function thermionic emission materials

Description: Thermionic energy conversion in a microminiature format shows potential as a viable, high efficiency, on-chip power source. Microminiature thermionic converters (MTC) with inter-electrode spacings on the order of microns are currently being prototyped and evaluated at Sandia. The remaining enabling technology is the development of low work function materials and processes than can be integrated into these converters. In this report, the authors demonstrate a method of incorporating thin film em… more
Date: November 1, 1999
Creator: Zavadil, K.R.; King, D.B. & Ruffner, J.A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Comparison among five hydrodynamic codes with a diverging-converging nozzle experiment

Description: A realistic open-cycle gas-core nuclear rocket simulation model must be capable of a self-consistent nozzle calculation in conjunction with coupled radiation and neutron transport in three spatial dimensions. As part of the development effort for such a model, five hydrodynamic codes were used to compare with a converging-diverging nozzle experiment. The codes used in the comparison are CHAD, FLUENT, KIVA2, RAMPANT, and VNAP2. Solution accuracy as a function of mesh size is important because, i… more
Date: September 1, 1999
Creator: Thode, L. E.; Cline, M. C.; DeVolder, B. G.; Sahota, M. S. & Zerkle, D. K.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Thermionic Converter Temperature Controller

Description: A method and apparatus for controlling the temperature of a thermionic reactor over a wide range of operating power, including a thermionic reactor having a plurality of integral cesium reservoirs, a honeycomb material disposed about the reactor which has a plurality of separated cavities, a solid sheath disposed about the honeycomb material and having an opening therein communicating with the honeycomb material and cavities thereof, and a shell disposed about the sheath for creating a coolant … more
Date: August 23, 1999
Creator: Shaner,B. J.; Wolf, Joseph H. & Johnson, Robert G. R.
Item Type: Refine your search to only Patent
Partner: UNT Libraries Government Documents Department
open access

The apparent anomalous, weak, long-range acceleration of Pioneer 10 and 11

Description: Recently the authors reported that radio Doppler data generated by NASA`s Deep Space Network (DSN) with the Pioneer 10 and 11 spacecraft indicate an apparent anomalous, constant, spacecraft acceleration with a magnitude {approximately}8.5 {times} 10{sup {minus}8} cm s{sup {minus}2}, directed towards the Sun. Analysis of similar Doppler and ranging data from the Galileo and Ulysses spacecraft yielded ambiguous results for the anomalous acceleration, but the analysis was useful in that it ruled o… more
Date: July 1999
Creator: Anderson, J. D.; Lau, E. L.; Turyshev, S. G.; Laing, P. A.; Liu, A. S. & Nieto, M. M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A Glove Box Enclosed Gas-Tungsten Arc Welding System

Description: This report describes an inert atmosphere enclosed gas-tungsten arc welding system which has been assembled in support of the MC2730, MC2730A and MC 3500 Radioisotope Thermoelectric Generator (RTG) Enhanced Surveillance Program. One goal of this program is to fabricate welds with microstructures and impurity levels which are similar to production heat source welds previously produced at Los Alamos National Laboratory and the Mound Facility. These welds will subsequently be used for high tempera… more
Date: July 1, 1999
Creator: Reece, M. & Robino, C. V.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Thermal Analysis of LANL Ion Exchange Column

Description: This document reports results from an ion exchange column heat transfer analysis requested by Los Alamos National Laboratory (LANL). The object of the analysis is to demonstrate that the decay heat from the Pu-238 will not cause resin bed temperatures to increase to a level where the resin significantly degrades.
Date: June 16, 1999
Creator: Laurinat, J.E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Characteristics of a Mixed Thorium-Uranium Dioxide High-Burnup Fuel

Description: Future nuclear fuels must satisfy three sets of requirements: longer times between refueling; concerns for weapons proliferation; and development of a spent fuel form more suitable for direct geologic disposal. This project has investigated a fuel consisting of mixed thorium and uranium dioxide to satisfy these requirements. Results using the SCALE 4.3 code system indicated that the mixed Th-U fuel could be burned to 72 MWD/kg or 100 MWD/kg using 25% of 35% UO2 respectively. The uranium remaine… more
Date: June 1, 1999
Creator: Herring, J. S. & MacDonald, P. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Monthly Progress Report Heat Source Technology Programs January to March 1997

Description: This quarterly report describes activities performed in support of Cassini fueled-clad production and studies related to the use of {sup 238}PuO{sub 2}in radioisotope power systems carried out for the Office of Special Applications of the U.S. Department of Energy (DOE) by Los Alamos National Laboratory (LANL). Most of the activities described are ongoing; the results and conclusions described may change as the work progresses.
Date: May 1, 1999
Creator: George, T. G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Operational comparison of bubble (super heated drop) dosimetry results with routine albedo thermoluminescent dosimetry for a selected group of Pu-238 workers at Los Alamos National Laboratory

Description: This paper is an operational study that compares the use of albedo thermoluminescent dosimeters with bubble dosimeters to determine whether bubble dosimeters do provide a useful daily ALARA tool that can yield measurements close to the dose-of-record. A group of workers at the Los Alamos National Laboratory (LANL) working on the Radioactive Thermoelectric Generators (RTG) for the NASA Cassini space mission wore both bubble dosimeters and albedo dosimeters over a period from 1993 through 1996. T… more
Date: March 1999
Creator: Romero, L. L.; Hoffman, J. M.; Foltyn, E. M. & Buhl, T. E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Containment of Nitric Acid Solutions of Plutonium-238

Description: The corrosion of various metals that could be used to contain nitric acid solutions of Pu-238 has been studied. Tantalum and tantalum/2.5% tungsten resisted the test solvent better than 304L stainless steel and several INCONEL alloys. The solvent used to imitate nitric acid solutions of Pu-238 contained 70% nitric acid, hydrofluoric acid, and ammonium hexanitratocerate.
Date: January 31, 1999
Creator: Reimus, M.A.H.; Silver, G.L.; Pansoy-Hjelvik, L. & Ramsey, K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Nitrate Anion Exchange in Pu-238 Aqueous Scrap Recovery Operations

Description: Strong base, nitrate anion exchange (IX) is crucial to the purification of {sup 238}Pu solution feedstocks with gross levels of impurities. This paper discusses the work involved in bench scale experiments to optimize the nitrate anion exchange process. In particular, results are presented of experiments conducted to (a) demonstrate that high levels of impurities can be separated from {sup 238}Pu solutions via nitrate anion exchange and, (b) work out chemical pretreatment methodology to adjust … more
Date: January 31, 1999
Creator: Pansoy-Hjelvik, M.E.; Silver, G.L.; Reimus, M.A.H. & Ramsey, K.B.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Decontamination and reconditioning of the Argonne National Laboratory-West Casting Laboratory alpha glove box

Description: The Casting Laboratory (CL) alpha glove box was used to melt and cast metallic uranium and plutonium fuels as part of the Department of Energy`s Liquid Metal Fast Breeder Reactor Program. This highly contaminated alpha glove box was decontaminated and reconditioned to allow a change in mission. The goal of reconditioning was to install experimental apparatus and to improve contamination control prior to introducing plutonium-238 into the CL glove box. Construction of a glove box containment str… more
Date: December 31, 1998
Creator: Poston, J.W. Jr. & Burke, L.L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Evaluation and characterization of General Purpose Heat Source girth welds for the Cassini mission

Description: General Purpose Heat Sources (GPHSs) are components of Radioisotopic thermoelectric Generators (RTGs) which provide electric power for deep space missions. Each GPHS consists of a {sup 238}Pu oxide ceramic pellet encapsulated in a welded iridium alloy shell which forms a protective barrier against the release of plutonia in the unlikely event of a launch-pad failure or reentry incident. GPHS fueled clad girth weld flaw detection was paramount to ensuring this safety function, and was accomplish… more
Date: December 31, 1998
Creator: Lynch, C.M.; Moniz, P.F. & Reimus, M.A.H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Heatpipe power system development

Description: This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of the project was to develop a design approach that could enable the development of near-term, low-cost, space fission-power systems. Sixteen desired attributes were identified for such systems and detailed analyses were performed to verify that they are feasible. Preliminary design work was performed on one concept, the Heatpipe Power … more
Date: December 31, 1998
Creator: Houts, M. G. & Poston, D. I.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Light-weight radioisotope heater impact tests

Description: The light-weight radioisotope heater unit (LWRHU) is a {sup 238}PuO{sub 2}-fueled heat source designed to provide one thermal watt in each of various locations on a spacecraft. Los Alamos National Laboratory designed, fabricated, and safety tested the LWRHU. The heat source consists of a hot-pressed {sup 238}PuO{sub 2} fuel pellet, a Pt-30Rh vented capsule, a pyrolytic graphite insulator, and a fineweave-pierced fabric graphite aeroshell assembly. To compare the performance of the LWRHUs fabric… more
Date: December 31, 1998
Creator: Reimus, M.A.H.; Rinehart, G.H. & Herrera, A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Nondestructive inspection of General Purpose Heat Source (GPHS) girth welds

Description: The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of {sup 238}Pu decay to an array of thermoelectric elements. The GPHS is fabricated using iridium capsules, TIG welded, to contain the {sup 238}PuO{sub 2} fuel pellet. GPHS capsules will be utilized in the upcoming Cassini mission to explore Saturn and its moons. The physical integrity of the girth weld is important to mission safety and performance. Since experience in the past had revealed a pote… more
Date: December 31, 1998
Creator: Reimus, M.A.H.; George, T.G. & Lynch, C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Nuclear modules for space electric propulsion

Description: Analysis of interplanetary cargo and piloted missions requires calculations of the performances and masses of subsystems to be integrated in a final design. In a preliminary and scoping stage the designer needs to evaluate options iteratively by using fast computer simulations. The Oak Ridge National Laboratory (ORNL) has been involved in the development of models and calculational procedures for the analysis (neutronic and thermal hydraulic) of power sources for nuclear electric propulsion. Th… more
Date: December 31, 1998
Creator: Difilippo, F. C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Radioisotope thermoelectric generator/thin fragment impact test

Description: The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of {sup 238}Pu decay to an array of thermoelectric elements in a radioisotope thermoelectric generator (RTG). Because the potential for a launch abort or return from orbit exists for any space mission, the heat source response to credible accident scenarios is being evaluated. This test was designed to provide information on the response of a loaded RTG to impact by a fragment similar to the type o… more
Date: December 31, 1998
Creator: Reimus, M.A.H. & Hinckley, J.E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Redefining design criteria for Pu-238 gloveboxes

Description: Enclosures for confinement of special nuclear materials (SNM) have evolved into the design of gloveboxes. During the early stages of glovebox technology, established practices and process operation requirements defined design criteria. Proven boxes that performed and met or exceeded process requirements in one group or area, often could not be duplicated in other areas or processes, and till achieve the same success. Changes in materials, fabrication and installation methods often only met imme… more
Date: December 31, 1998
Creator: Acosta, S.V.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Reducing the risk to Mars: The gas core nuclear rocket

Description: The next giant leap for mankind will be the human exploration of Mars. Almost certainly within the next thirty years, a human crew will brave the isolation, the radiation, and the lack of gravity to walk on and explore the Red planet. However, because the mission distances and duration will be hundreds of times greater than the lunar missions, a human crew will face much greater obstacles and a higher risk than those experienced during the Apollo program. A single solution to many of these obst… more
Date: December 31, 1998
Creator: Howe, S.D.; DeVolder, B.; Thode, L. & Zerkle, D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Characterization of Sputter Deposited Thin Film Scandate Cathodes for Miniaturized Thermionic Converter Applications

Description: We have successfully developed a method for fabricating scandate-based thermionic emitters in thin film form. The primary goal of our effort is to develop thin film emitters that exhibit low work fimction, high intrinsic electron emissivity, minimum thermal activation properties and that can be readily incorporated into a microgap converter. Our approach has been to incorporate BaSrO into a SqOq matrix using rf sputtering to produce thin films. Diode testing has shown the resulting films to be … more
Date: December 14, 1998
Creator: King, D.B.; Ruffner, J.H. & Zavadil, K.R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

GPHS-RTGs in support of the Cassini RTG Program. Addendum to the final technical report, May 1--December 31, 1998

Description: This Addendum to the Cassini GPHS-RTG Program Final Technical Progress Report describes activities performed during the period 1 May 1998 through 31 December 1998, including effort reflecting contract modification M058. These activities include Earth Gravity Assist (EGA) reentry and related analyses which are detailed in Part A, and effort related to the installation of CAGO equipment within Lockheed Martin`s Building 100 facility in Valley Forge, PA, which is detailed in Part B.
Date: December 1, 1998
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Monthly Progress Report Heat Source Technology Programs October through December 1996

Description: This quarterly report describes activities performed in support of Cassini fueled-clad production and studies related to the use of 238Pu02 in radioisotope power systems carried out for the Office of Special Applications of the U.S. Department of Energy (DOE) by Los Alamos National Laboratory (LANL). Most of the activities described are ongoing; the results and conclusions described may change as the work progresses.
Date: December 1, 1998
Creator: George, T. G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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