On April 14–15, 2026, the second semi-annual meeting within the framework of the L’Opera project was held at the Faculty of Nuclear Sciences and Physical Engineering of the Czech Technical University in Prague. Senior Researcher Zlobenko B.P. participated as a project participant from the Institute of Environmental Geochemistry of the NAS of Ukraine with a report “Testing the strength and stability of geopolymer matrices for waste”. The L’Opera project is part of the European EURAD 2 program, which is funded by the European Commission. Experts from 8 countries and 22 organizations came to Prague to discuss research in the field of materials science for radioactive waste. The L’Opera project is dedicated to the study of geopolymers and alternative matrices for the immobilization of radioactive waste, as well as their long-term behavior in repository conditions. An excellent event for discussing and exchanging experience with international partners and further joint development of this research. The meeting was organized by a group of representatives from the Rež Nuclear Research Center, CVUT, and SÚRAO.