Institut für Material- und Festkörperforschung II, Kernforschungszentrum Karlsruhe GmbH, Karlsruhe,
Pages: 17 Published: Jan 1984
A comparative study of the oxidation behavior of Zircaloy-4 versus austenitic stainless steel No. 1.4970 was performed in high-temperature steam. Nuclear reactor-type tube sections of both materials were exposed on both sides to superheated steam at temperatures ranging from 600 to 1300°C for up to 6 h. The specimens were evaluated by gravimetry, metallography, and other methods. The results are presented in terms of weight gain, corresponding metal consumption, and wall penetration as functions of time and temperature. The two materials behaved similarly in that the faster oxidation of the thicker Zircaloy-4 cladding consumed the total wall thickness in a time equivalent to the slower oxidation of the thinner stainless steel cladding. Besides oxide scale formation, oxygen diffusion into the bulk of the metal formed various oxygen-containing phases, which together influence the mechanical cladding properties. Remarkable swelling of tube dimensions was caused by oxidation.
loss-of-coolant accident, severe core damage, Zircaloy-4 cladding, austenitic stainless steel cladding, steam oxidation, metal consumption, wall penetration, dimensional changes, heat, hydrogen production
Paper ID: STP34507S