Technical Report NTB 90-33

Poços de Caldas Report No. 15Summary and implications for radioactive waste management

This report provides an overview of the Poços de Caldas natural analogue study, aspects of which have been described in detail in the previous 14 reports of this series.

The first part of this report provides the historical background to the project, describes the research programme developed at the Osamu Utsumi and Morro do Ferro sites and summarises the main findings of the geological, hydrologic and geochemical characterisation work.

This is followed by reviews of the four analogue sub-projects – testing geochemical models of trace element solubility and speciation, evaluation of models of redox front development and movement, examining the role of natural colloids as a vector for transport of trace elements and appraisal of a modelling approach to quantifying hydrothermal alteration and solute transport processes.

Finally, the direct implications of the project to radioactive waste management are discussed along with some valuable spin-off which was identified. Such a large multidisciplinary study proved a very valuable focus for forging contacts between specialists – from different disciplines in a manner closely analogous to that required for an integrated site assessment. The iterative development of the modellers' wish lists and the field/lab analytical programme was a key to the success of this Project and provides guidelines for site-specific performance assessment.