Recovery in Stabilized Delta Pu and its Effects on Thermophysical Properties

Recent efforts at Los Alamos National Laboratory (LANL) have focused on thermodynamic measurements of aged and pre-conditioned delta alloys at temperatures in the vicinity of defect recovery and stored energy release. In both scenarios, quantifiable thermophysical property changes are observed across temperatures ranging from 125-225 °C. Analogous behavior in Pu has been observed via electrical resistivity measurements, which has been attributed to migration of point defects, dislocations, and vacancy clusters. Whether interactions between defects produced by pre-conditioning or natural aging can develop into alpha-like embryos, which can lead to decomposition of the delta phase, remains to be seen. Consequently, ongoing thermal analysis work is being conducted at LANL on a comprehensive series of pre-conditioned and naturally aged Pu-Ga alloys and the ensuing results in the context of delta phase stability will be discussed.