The oxides of the transuranic elements have been the subject of numerous investigations since the discovery of neptunium (Np) and plutonium (Pu) in 1940–1941. Similar to uranium oxides, they are stable under atmospheric conditions and do not require complicated synthesis. Once they were produced in substantial quantities they became available for experiments. Early research included their structural, magnetic, and thermodynamic characterization, mainly at ambient and cryogenic temperatures. Only in the 1960s were systematic studies undertaken on the (very) high-temperature properties of the oxides of the transuranic elements. This was in part because the uranium-plutonium mixed dioxide was becoming the prevailing fuel choice for fast reactors, and because the well-studied metal fuel exhibited dimensional instability during irradiation for which solutions were not easily found. Oxide fuel operates at a much higher temperature, only a few hundreds of kelvins below melting, resulting in an almost complete fission gas release, and, hence, a remarkable stability up to high burnup.

KONINGS Rudy;  MANARA Dario;  GUENEAU Christine; 

2013-12-19

Glenn T. Seaborg Institute at Los Alamos National Laboratory

JRC79540

http://arq.lanl.gov/issues/2013/volume2.pdf,    https://publications.jrc.ec.europa.eu/repository/handle/JRC79540,