Initial stage of helium clustering in UN and PuN

Synthesis and Properties of the Helium Clathrate and Defect Perovskite [He2–x□x][CaNb]F6

“…For example, α decay in nuclear fuel results in the formation of helium that can, in principle, lead to bubble formation, fuel element swelling, and possibly failure. Consequently, there have been studies of the solubility and energetics of helium incorporation in materials such as actinide dioxides, and also its diffusion through the materials. − There has also been interest in the formation of helium compounds with iron, and iron oxide, in the context of exoplanet interiors and deep earth minerals, − as these materials could be important in accounting for helium abundance in the earth and solar system. The boundaries of helium chemistry have been further expanded by preparing the electride Na 2 He at >113 GPa .…”