témavezető: Fábián Margit
belső konzulens: Pátzay György
helyszín (magyar oldal): MTA Energiatudományi Kutatóközpont helyszín rövidítés: MTAEK
A kutatási téma leírása:
Vitrification of high-level radioactive waste (HLW) has received greater attention, worldwide, than any other HLW solidification process. Essentially important task in this area is, to find a simple and an understandable process where we can immobilize the HLW materials.
Since the time frame for calculating the performance of the HLW glass in a geological repository is very long, even slow water/glass interaction phenomenon need to be understood well for developing mathematical formulations for predicting the performance. Data related to water/glass interaction, both leaching and general corrosion, are considered essential to the development of performance assessment models. The term, chemical durability, as it is used for glass waste form refers to its resistance to attack by aqueous solutions measured as a rate of dissolution or by elemental release.
The aim of the planned research is the synthesis, structural investigation, chemical durability test and corrosion studies of borosilicate glasses. New glass compositions will be synthesized with inactive (Ce, Nd, Eu) and radioactive (U) elements for safe storage of radioactive waste including a new technology for vitrification. For chemical modelling of the actinides we use lanthanides; Ce for the hazardous radioactive Pu, while Nd for Am and Eu for Cm. The atomic structure of the samples will be investigated by combined neutron- and X-ray diffraction and X-ray absorption measurements. Using Reverse Monte Carlo modelling, the partial atomic pair-correlation functions will be determined, providing structural data for the short- and medium-range order.
Chemical durability tests are planned on the investigated samples, the test periods will be typically in the order of days to months, on different temperatures between ambient and 80°C. Further task is the understanding the dissolution or corrosion rate of the glasses, using laboratory experiment involving clay rock from Boda Claystone Formation which is the planned Hungarian host rock for the deep-geological disposal project. Chemical analysis of leachates from both type of tests will be also the task of applicant.
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