Characterization of Aluminum Metal Powders for Plutonium-238 Program
As part of radioisotope thermoelectric generator (RTG) production for power sources in deep space exploration, Oak Ridge National Laboratory (ORNL) produces plutonium-238 (238Pu). To produce 238Pu, neptunium-237 (237Np) targets are fabricated at ORNL and subsequently irradiated at the High Flux Isotope Reactor (HFIR) at ORNL and the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL). Specifically, current flowsheets utilize neptunium dioxide (237NpO2) targets. Aluminum (Al) powder is blended with 237NpO2 target material to improve thermal conductivity during irradiation. The current composition of 237NpO2/Al pellets (i.e., cermets, or ceramic–metallics) is 20% 237NpO2, 70% Al, and 10% void space. Al powders utilized by the 238Pu program are high-fired under vacuum before blending into targets. The primary objective of this work is to measure the physical, chemical, and thermal properties of Al before and after the high-firing process. Properties of interest include the morphology, surface texture, particle size, crystal phase(s), and thermal conductivity of the material. These properties are measured with existing materials characterization equipment at ORNL, including powder x-ray diffraction (pXRD), scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS), laser flash analysis (LFA), and thermogravimetric analysis (TGA). A secondary objective of this work is to compare the Al powders before and after the high-firing procedure to determine the effects of high-firing on chemical, physical, and thermal properties and to determine the efficacy of the high-firing process.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1984345
- Report Number(s):
- ORNL/TM-2023/2896; TRN: US2403677
- Country of Publication:
- United States
- Language:
- English
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