Temperature Accelerated Aging Effects of Plutonium and Plutonium Based Materials

Aging effects resulting from the radioactive decay of Pu/Pu-materials have been shown to be accelerated at low temperatures, as at low temperatures the E = k_BT energy is not sufficient to anneal away defects induced by said decay. In strongly correlated elemental Pu, these effects manifest in physical properties such as magnetization and its local atomic structure. Similar manifestations have been observed in the transport properties of superconducting PuCoGa₅. Yet, no previous studies attempted to quantify the amount of total entropy associated with low temperature accelerated aging, nor did they find a lot success in quantitatively modeling the local disordered structure of Pu/Pu-materials resulting from decay induced defects. Recently, we have placed an initial bound on the total entropy associated with low temperature aging via specific heat measurements. Our initial results indicate there is a non-negligible and possible “universal” entropy scale for all Pu-materials studied. This is very important as studies of chemical and physical properties associated with the aging of Pu could be vastly hastened beyond its half-life (24 K years). Using pair distribution function, we begin to attempt to marry this scale to disorder local structure models to correlate Pu-aging properties/structures of interest to the Los Alamos National Laboratory.