Experimental study into ordered BaO-deficient Ba3PuO6

The Ba-Pu-O system is a key system in the understanding of irradiated oxide fuel, which is used in both Light-Water Reactors and next-generation reactors like the Sodium-cooled Fast Reactor and Lead-cooled Fast Reactor. However, experimental studies into the Ba-Pu-O system are quite limited and date most often back to last century. Herein, new experimental research into BaO-deficient Ba3PuO6 and BaPuO3 will be presented. These materials were investigated structurally, using X-ray diffraction at ambient and non-ambient temperature. Room-temperature and high-temperature crystal structures were elucidated and the thermal expansion was determined. Moreover, the low-temperature heat capacity has been measured, yielding both the standard entropy and heat capacity at 298.15 K. [1] The insights gained in this studies are key to the development of an accurate thermodynamic model of oxide fuel at higher burnup. Next, thermal expansion data of the materials is important for fuel performance codes.
[1] van Hattem, Andries, et al. "Structural and physical investigation of ordered BaO-deficient Ba3PuO6." Communications Chemistry 8.1 (2025): 270.