Dark patinas rich in manganese (Mn) developed on several sandstones of the Lunéville château (France) contrasting with the general yellow color of the building. The characterization of the Mn compounds in the patinas, but also in the building stones, allowed us to propose a model for the patina formation based on the dissolution of the Mn phases initially present in the stone bulks. The results obtained in this study might enlighten processes occurring on other buildings or in natural settings.

The present contribution provides an overview on the collaborative project iCROSS and reports selected results. The impact of considering complex coupled processes in repository subsystems for the assessment of the integrity of a given (generic) repository arrangement will be discussed. The interdisciplinary team combines experimental work in the lab, in the underground rock laboratory and environmental simulations in order to achieve process understanding across variable scales.

An overview on the recent advances in the field of high temperature studies of radionuclides in aqueous solutions will be given. Besides summarizing information on key technical aspects relevant for high temperature studies, the effect of increased temperatures on the complexation of trivalent actinides with chloride will be discussed in more detail, to illustrate newly derived in-depth understanding of the impact of increased temperatures on the (geo)chemical behaviour of trivalent actinides.