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.

Synthesis, Characterization, and Stability of Americium Phosphate, AmPO.

AmPO was prepared by a solid-state reaction method, and its crystal structure at room temperature was solved by powder X-ray diffraction combined with Rietveld refinement. The purity of the monazite-like phase was confirmed by spectroscopic (high-resolution solid-state P NMR and Raman) and microscopic (SEM-EDX and TEM) techniques. The thermal and self-irradiation stability have been studied.

Plutonium and Americium Aluminate Perovskites.

Both AmAlO and PuAlO perovskites have been synthesized and characterized using powder X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), and Al magic angle spinning nuclear magnetic resonance spectroscopy (MAS NMR). AmAlO perovskite showed a rhombohedral configuration (space group 3̅) in agreement with previous studies. The effect of americium α-decay on this material has been followed by XRD and Al MAS NMR analyses.

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.

On the Role of the Electrical Field in Spark Plasma Sintering of UO.

The electric field has a large effect on the stoichiometry and grain growth of UO during Spark Plasma Sintering. UO is gradually reduced to UO as a function of sintering temperature and time. A gradient in the oxidation state within the pellets is observed in intermediate conditions.