Keywords: low-alloy steel, air oxidation, nuclear waste, waste package design, nuclear energy, nuclear power, outer wall material, kinetics
Oxidation characteristics of A588 steel and its applicability to high-heat-load nuclear waste package designs
The ASTM A588 steel is proposed as the outer wall material for second-generation nuclear waste package designs (Armijo et al., 2006; Kar, 2006). Oxidation weight-gain kinetics was evaluated for the A588 steel by thermal-gravimetric method at a range of temperatures (475°C to 600°C). Isothermal oxidation tests were conducted in dry air. Oxidation at lower temperatures followed parabolic kinetics and that at temperatures above 575°C was faster. The morphology and composition of the scales, formed at 475°C, favour the applicability of the A588 steel. Assuming a realistic activation energy and oxide scale growth rate, the calculated metal penetration depth was determined to be very small. The protective nature of the oxide scale on the steel is investigated in this work and discussed in relevance to the second-generation waste package and the other high-heat-load waste package designs (Kar et al., 2006; 2008).