Copper-coated steel containers are part of the engineered barrier system to permanently store Canadian nuclear fuel waste in a deep geological repository. This work models the dose rates (D Rs) at the container surfaces as a function of fuel age. It also utilises a humid-air radiolysis model to study the effects of D R and humidity on radiolytic oxidant production for conditions where unexpected early water intrusion reaches clay seal materials. Radiolysis of humid air produces HNO 3. The HNO 3 production rate in a condensed water droplet formed on a container surface was conservatively estimated by assuming that every •OH produced by primary radiolytic processes was immediately converted to HNO 3 in the gas phase and that all of the HNO 3 was absorbed in the water droplet. Also assuming that all of the nitric acid absorbed in the water droplet is consumed in corroding copper and using a hemispherical water droplet geometry, the corrosion depth of the copper coating induced by humid-air radiolysis is conservatively estimated to be 9.4 μm over the permanent storage time.

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