Properties of Liquid Plutonium

Unalloyed polycrystalline Pu displays extreme thermal expansion behavior, i.e., α → β → γ → (delta) increases by 25% in volume and (delta) → (varepsilon) → liquid decreases by 4.5% in volume. Thus, making it difficult to measure density into the liquid state. Dilatometer outfitted with CaF molten metal cell offers a proven capability to measure thermal expansion in molten metals, but has yet to be proven for Pu. Historic data from the liquid nuclear fuels program will prove extremely useful as a guide to future measurements. 3.3at% Ga changes Pu molten metal properties: 50% increase in viscosity and ∼3% decrease in density. Fe may decrease the density by a small amount assuming an averaging of densities for Pu-Ga and Pu-Fe liquids. More recent Boivineau (2009) work needs some interpretation, but technique is being employed in (U,Pu)O2 nuclear fuels program (Pu Futures, 2012).