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One of the possible consequences of a loss-of-coolant accident (LOCA) in a light-water reactor would be the rapid heatup of the fuel tubes in a steam environment. During the period of time in which the cladding was exposed to steam (provided both from boiloff of residual water in the pressure vessel and by the emergency coolant) at elevated temperatures, reaction of the Zircaloy with the steam would cause the formation of an oxide film on the cladding surface and an oxygen gradient into the wall. Since the ductility of Zircaloy is a direct function of oxygen content, and since the oxygen content is a function of time and temperature of steam exposure, a study of the degree of embrittlement to be expected in a LOCA necessitates the examination of specimens exposed to specific temperatures for given lengths of time in a steam environment. Correlations are developed among steam exposure, oxygen content, ductility, and hardness which permit estimating the degree of embrittlement the cladding would attain during any LOCA transient. Curve fitting to LOCA transient data and subsequent integration provide easy analysis of the amount of embrittlement expected.

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