Correlation and Predicfion of Explosive Metal-Water Reaction Temperatures

The fast, potentially hazardous chemical reaction between a metal and water can occur in a nuclear reactor only above the melting point of the metal, Tm. There is a critical temperature, theta > Tm, at which the process changes over from the slow corrosion-like reaction to one which proceeds with explosive speed and violence. For the alkali metals, theta is only slightly greater than Tm. The critical temperature theta was experimentally determined for three high melting point metals, Al, Zr, and U, and it is shown that theta is approximately equal to the temperature at which the metal vapor pressure is 0.15 mm for these cases. This relation suggests that the initiation of the violent metalwater reaction for refractory metals may be a vapor phase phenomenon. On the basis of this hypothesis, and the empirical correlations developed, predictions of the value of theta are presented for a number of other metals for which experimental data are not presently available. (auth)