The Melt Enthalpy of Pu6Fe

Schwartz, et al., previously reported calorimetry measurements conducted on a Pu-Pu6Fe mixture, from which they derived a melt enthalpy of 31.2 J/g (46.6 kJ/mol) for Pu6Fe. This was the first-and remains the only-such value to appear in the literature. We reanalyze those results in light of two contributions to the measured heat flow not considered in the original report: the melt enthalpy of the excess Pu and the subsequent heating of the liquid mixture. These corrections yield a revised value of 24.4 J/g (36.3 kJ/mol), which we show to be consistent with the melt enthalpy of U6Fe.