Synthesis, Characterization, and Stability of Two Americium Vanadates, AmVO and AmVO.

In search for chemically stable americium compounds with high power densities for radioisotope sources for space applications, AmVO and AmVO were prepared by a solid-state reaction. We present here their crystal structure at room temperature solved by powder X-ray diffraction combined with Rietveld refinement. Their thermal and self-irradiation stabilities have been studied.

Synthesis and characterization of homogeneous (U,Am)O and (U,Pu,Am)O nanopowders.

This paper details the first dedicated production of homogeneous nanocrystalline particles of mixed actinide oxide solid solutions containing americium. The target compositions were UPuAmO, UAmO and UAmO. After successful hydrothermal synthesis and chemical characterisation, the nanocrystals were sintered and their structure and behaviour under self-irradiation were studied by powder XRD.

Structural and Thermodynamic Investigation of the Perovskite BaNaMoO.

Neutron diffraction, X-ray absorption spectroscopy (XAS), and Raman spectroscopy measurements of the quaternary perovskite phase BaNaMoO have been performed in this work. The cubic crystal structure in space group 3̅ has been refined using the Rietveld method. X-ray absorption near-edge structure spectroscopy (XANES) measurements at the Mo K-edge have confirmed the hexavalent state of molybdenum.

Kinetic study on the grain growth of PuO nanocrystals.

Kinetic measurements on the grain growth of PuO nano-crystals are presented. On the basis of isothermal XRD measurements at temperatures of 820 °C, 900 °C, 1000 °C, and 1100 °C the activation energy for the crystallite growth of PuO nanopowder is determined as 351(5) kJ mol in the temperature range from 820 to 1000 °C. Modelling shows that in this range growth happens likely through surface diffusion.

Optimization of Uranium-Doped Americium Oxide Synthesis for Space Application.

Americium 241 is a potential alternative to plutonium 238 as an energy source for missions into deep space or to the dark side of planetary bodies. In order to use the Am isotope for radioisotope thermoelectric generator or radioisotope heating unit (RHU) production, americium materials need to be developed. This study focuses on the stabilization of a cubic americium oxide phase using uranium as the dopant.