The preparation and some properties of plutonium fluorides

Chemical Disposition of Plutonium in Hanford Site Tank Wastes

“…The chemical and physical dispositions of plutonium in the starting Hanford process materials, in solution by itself and with various anions and other metal ions, as solid compounds, in adsorption reactions, and after treatment with NaOH to be made alkaline for tank waste storage are summarized in Table 7-2. (Dawson et al 1954b). Conversion of PuF 4 to PuF 4 •2.5 H 2 O is known to occur in HF solution (Dawson et al 1954a) and it is likely that this conversion also transpires in water.…”

The Chemical Thermodynamic Properties of Plutonium Compounds

“…The resulting calculation using this recent heat of formation of PuCl3 gives the heat of formation of PuF3 as -374.4 kcal/mole. Later studies on the precipitation of PuF3 from hydrofluoric acid solution revealed the presence of occluded water in the precipitated PuF3 (30) which means a slight correction to the heat of formation of PuF3 as it was assumed in the precipitation measurements that the PuF3 was anhydrous. It is difficult to make a correction for the occluded water as the precipitate is probably not a definite complex since it begins to lose weight as soon as the temperature is raised, and the amount of water it contains varies with the temperature of precipitation (30).…”

“…Later studies on the precipitation of PuF3 from hydrofluoric acid solution revealed the presence of occluded water in the precipitated PuF3 (30) which means a slight correction to the heat of formation of PuF3 as it was assumed in the precipitation measurements that the PuF3 was anhydrous. It is difficult to make a correction for the occluded water as the precipitate is probably not a definite complex since it begins to lose weight as soon as the temperature is raised, and the amount of water it contains varies with the temperature of precipitation (30). Rand (92) has estimated the heat of hydration of PuF3 to be -3.4 ± 2.5 kcal/ mole by comparison with the heats of hydration of ThF4 and UF4 to their 0.4 hydrates (39) which have surprisingly different values of -1.2 and -6.1 kcal/ mole.…”

“…The heat of formation of plutonium tetrafluoride at 298°K can be derived from the equilibrium data on the reaction 4PuF8(c) + 02(g) <=í 3PuF4(c) + Pu02(c) The equilibrium pressure of oxygen from this reaction has been given as 7.2 mm at 783°K and 7.5 cm at 1073 °K (30). The free energy of formation of PuF4 at these respective temperatures is then calculated from the free-energy change for the above reaction and the free energy of formation of the other components taken from Tables IX and X, respectively.…”

The Potential Interactions of Novec 1230 and Its Thermal Degradation Products with Actinide Metals and Oxides

“…As shown in Scheme for Pu, a series of controlled events would need to occur to convert PuO 2 to PuF 6 . The PuO 2 can react with the TDP HF between room temperature and 150 °C to possibly form intermediate compounds (i.e., Pu(OH) 2 F 2 and Pu(OH)F 3 ) that would then form PuF 3 or PuF 4 if a reducing or oxidizing atmosphere is present, respectively. The ideal temperature for the reaction: PuO 2 + 4 HF + normalO 2 → PuF 4 + 2 normalH 2 normalO + normalO 2 is 550 °C (500 °C for Np and 550 °C for U and Th). ,, While the incipient formation of PuF 4 via hydrofluorination has been observed at considerably lower temperatures (e.g., 200 °C), the aforementioned reactions are kinetically slow .…”