In situ observation of incorporation processes
My work is motivated by the long term safety assessment of nuclear waste disposal in geological formations and the occurrence of a possible incident like the intrusion of groundwater and the following release of radionuclides. The retention mechanism of the geochemical barrier and the surrounding rocks are subject of recent research. Long-lived actinides require a prediction of the safety for 1 Ma.
Calcite is present as secondary phase (weathering of the geochemical barrier) and as rock-forming Mineral in the surrounding rocks. It has the property to incorporate guest ions into the bulk.
These incorporation processes (solid solutions) are the subject of my research. Under near equilibrium conditions over a period of one year calcite get the possibility to incorporate curium (in a first step europium as a non-radioactive equivalent). The single steps of incorporation and the species, which occur, will be characterized with site-selective TRLFS.
Furthermore investigations with RAXR and CTR should be conducted. So an understanding on a molecular level can be reached. In addition it is contrived to investigate other minerals, which can incorporate guest ions (e.g. aragonite, aluminaphases) and to compare the different mechanism of incorporation.