Natural and archaeological analogues for corrosion prediction in nuclear waste systems

Natural and archaeological analogues can be a powerful means to build confidence in the long-term prediction of corrosion in nuclear waste systems. Analogues are meaningful to both experts and lay audiences. Useful analogues exist to support the long-term behaviour for both copper and steel used fuel containers (UFC) and examples are given for the corrosion processes that are, and are not, expected to occur under repository conditions for both materials. The concept of kinetic versus thermodynamic stability is used to explain the persistence of such analogues. The use of analogues to support the prediction of the long-term corrosion performance of the UFC in the safety case is also discussed. While there have been a wide range of analogue studies in the past, it is suggested that future studies should be focussed on addressing specific aspects of the treatment of corrosion issues in the safety case.