THE VOLATILITY OF PuO2 IN NONREDUCING ATMOSPHERES

摘要

The vapor pressure of plutonium dioxide (PuO2) was investigated in the temperature range 1450 to 1775 C (1723 to 2048 K) in air, argon, and oxygen atmospheres by a transpiration technique. Data and thermodynamic calculations showed that Pu02 can vaporize congruently or as a suboxide species, probably PuO, depending on the atmosphere. The ΔH298 for vaporization in 1 atm of oxygen is 153,800 cal per mole. The standard free energy of formation (ΔGf) of gaseous PuO2 is -121,000+ 10.7T from 1227 to 1827C (1500 to 2100 K). The calculated erosion loss is approximately 3 mils per yr at 1705 C (1978 K).