Bukov URF II – the new section of the operated Czech generic underground research laboratory: selected results from construction‑phase characterisation

The Radioactive Waste Repository Authority (SÚRAO) is the national organisation responsible for the safe management and disposal of radioactive waste in the Czech Republic. One of the key components of its long‑term mission concerns the development of the country’s deep geological repository (DGR), which is currently advancing via a structured programme of research, design and stakeholder engagement. Aimed at supporting the pre‑implementation phase, SÚRAO is currently conducting an extensive research, development and demonstration (RD&D) programme using a number of generic underground research laboratories, which provide the experimental conditions required to verify the repository concept prior to the selection of the final site (Smutek et al., 2023).The Bukov Underground Research Facility (URF), including its recent extension - Bukov URF II, fulfils a central role in the RD&D framework. The facility is situated on the 12th level of the former Rožná I uranium mine, approximately 500 metres below the surface. Bukov URF II consists of 6 laboratory corridors and a total of 13 test chambers. The excavation of the Bukov II galleries was completed in April 2024, and the facility entered operation in 2025.The geological and geotechnical characterisation of Bukov URF II is focusing on forming an understanding of the structural, lithological, hydrogeological and mechanical properties of the Moldanubian crystalline rock basement. Recent investigation research - including detailed structural mapping, core logging, hydrogeological tests, geophysical surveys and in‑situ stress measurements – has provided the data required to make a high‑resolution assessment of the rock mass. The data form the basis for designing and evaluating repository‑relevant experiments, including the testing of the engineered barrier system and the validation of the technical design of the DGR (Hausmannová et al., 2025). The comprehensive results assist in further refining the understanding of deformation structures, fracture network connectivity, geomechanical behaviour and rock mass quality across the newly-excavated spaces of Bukov URF II (Bukovská et al. 2025). Together, these findings significantly strengthen the evidence base for the Czech DGR programme and its continued technical development.References:Bukovská Z., Soejono I., Rukavičková L., Chabr T., Morávek R., Levý O., Sosna K., Souček K., Vavro M., Řihošek J., Zelinková T., Pořádek P., Švagera O., Kryl J., Hanák J., Čermák F., Kašpar R., Mareček L., Nedvěd J., Vavro L., Staš L., Georgiou L., Janeček I., Zuna M., Kočan K., Třískalová I., Velímková A. (2025): Geological and geotechnical characterisation of the rock environment – Bukov URF II – English summary. – TZ812/2025/ENG, SÚRAO, Prague.Hausmannová L, Augusta J. Dohnálková M., Golubko A., Lahodová Z., Matušková E., Mecová M., Smutek J., Valter M., Vencl M. (2025): Technical design of the deep geological repository 2025, SÚRAO TZ 848/2025/ENG REV.1, Prague.Smutek J., Augusta J., Dohnálková M., Golubko A., Hausmannová L., Mareda L., Matulová M., Mikláš O., Vondrovic L. (2023): The Bukov URF research, development and demonstration activities programme 2023. TZ 683/2023/ENG, SÚRAO, Prague.