Scientific Highlights

In a deep geological repository, low and intermediate level radioactive waste from nuclear applications is solidified by cementitious materials for several thousand years. Researchers from the Paul Scherrer Institute and the Karlsruhe Institute of Technology have now demonstrated how cement limits the mobility of those radioactive substances. The new findings improve our understanding of the processes involved in this early phase of deep geological disposal.

A study by the Centre for Technology Assessment TA-Swiss, coordinated by the Paul Scherrer Institute, recommends further pursuing deep geothermal energy in Switzerland. The energy resources underground are vast, environmentally friendly to extract and available around the clock, the authors conclude. The earthquake risk and the cost of electricity production, which are still too high, however, remain challenges that society needs to weigh up against the advantages of deep geothermal energy.

Researchers from the Paul Scherrer Institute (PSI) and the Hungarian Academy of Sciences joined forces within an EU project to investigate the basic properties of argillaceous rocks in a repository for high-level radioactive waste. As the results reveal, the insights gained so far for Opalinus Clay can be transferred also to the Boda Clay found in Hungary.

Chemical reactions will change the nature of the deep repository and the surrounding rock (clay rock); that much is certain. But to what extent and with what impact on safety? Researchers from the Paul Scherrer Institute are looking to answer this question with the aid of a combination of experiments and computer simulations.

How do radioactive substances move through the host rock in a deep repository for nuclear waste? Researchers from the Diffusion Processes Group in the Laboratory of Waste Management at the Paul Scherrer Institute (PSI) have been investigating. The transport properties of negatively charged radionuclides, which are repelled by the negatively charged surfaces of clay minerals and thus hardly adhere to the rock, are well known. An EU project in which the PSI is also involved is now yielding similar insights into positively charged and therefore highly adherent radionuclides.

Radioactive waste from nuclear power plants, as well as from medical applications, industry and research, has to be isolated from the environment, particularly the habitat of humans, for a very long time. Specialists at PSI have been concerned with the safety issues surrounding safety certification for geological repositories for many years. Research at PSI focusses primarily on the physico-chemical processes inside such storage systems. The aim is to create a realistic description of the risks associated with storage of radioactive waste.