The solubility of helium in uranium dioxide was calculated directly from atomic properties and compared with experiment. The calculations were based upon a statisticalhyphen;mechanical formula which assumes dissolved helium to behave as a simple harmonic oscillator in an interstitial site in the UO2lattice. Knowledge of the interactions between helium and the oxygen and uranium ions of the lattice permits computation of the heat of solution and the vibration frequency, which yield the Henry's law constant. The calculated solubility of 6.6times;10minus;4cc (STP)/gmiddot;atm at 1200deg;C was in good agreement with the experimental measurements, but the heat of solutions differed appreciably. This discrepancy was attributed to experimental errors, for the very large observed heat of solution (sim;minus;30 kcal/mole) could not arise from purely physical interactions.
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