X‐ray diffraction, differential scanning calorimetry and evolved gas analysis of aged plutonium tetrafluoride (PuF4)

• DOI: 10.1007/s10967-021-07810-z
• Publication Date: 2021-06-23T04:04:14Z
• Authors: David M. Wayne; Jared T. Stritzinger; Amanda J. Casella; Lucas E. Sweet; Jordan F. Corbey; Daniel J. Garcia; E. Miller Wylie; Lav Tandon; Angela C. Olson; Jung Ho Rim
• Keywords: 01 natural sciences; 0104 chemical sciences

A 30 year-old PuF4 sample consisting of brown powder (PuF4-b) and pink granules (PuF4-p) was analyzed. X-ray diffraction shows the bulk is comprised of three compounds: PuF4, PuO2, and PuF4·1.6H2O. Broadening of PuF4 XRD peaks suggests possible $$\upalpha$$ -damage. After annealing at 650 °C, crystalline PuF4 and PuO2 remain. Thermogravimetric analysis and differential scanning calorimetry—with simultaneous evolved gas analysis—of the separated PuF4-p and PuF4-b components reveal a distinct sequence of reactions. Dehydration occurs between ~ 90 and 300 °C. Exothermic annealing of the $$\upalpha$$ -damage occurs in two stages: at 350–355 °C and at 555–558 °C. Hydrofluoric acid, fluorine and helium desorb during the first exotherm. Above 700 °C, PuF4 reacts with PuO2, resulting in oxygen release and mass loss.