Sören Kliem

Dr. Sören Kliem is the Head of the Reactor Safety Department at the Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), a leading German research center in nuclear and environmental sciences. He holds a PhD from the Technical University Dresden and has been a key figure in reactor safety research since joining Forschungszentrum Rossendorf in 1994. He leads a department focused on advanced nuclear safety analysis, code development, and experimental validation.

Education:

• PhD, Technical University Dresden, Faculty of Machinery Building, 2010
• Diploma, Moscow Power Engineering Institute (MEI), 1992

His research interests include reactor dynamics, nuclear accident analysis, thermal-hydraulics, neutron kinetics, coolant mixing in PWRs, and the development and validation of coupled simulation codes such as DYN3D and ATHLET. He is actively involved in EU-funded projects like Horizon 2020 R2CA, McSAFER, and EURATOM EASI-SMR, focusing on the safety of conventional and innovative reactor designs, particularly small modular reactors (SMRs).

The 15 most recent publications reflect a strong focus on reactor safety modeling, including boron dilution transients, severe accident management, code validation using experimental data (e.g., from ROCOM), and the application of high-fidelity simulation tools (CFD, coupled codes) to nuclear safety problems. His work emphasizes both numerical simulation and experimental benchmarking, particularly in the context of PWRs and VVER reactors.

Scientific Projects:

• Horizon 2020 R2CA: Reduction of radiological consequences of design basis and design extension accidents (2019–2023)
• Horizon 2020 McSAFER: High-Performance Advanced Methods and Experimental Investigations for the Safety Evaluation of Generic Small Modular Reactors (2020–2023)
• Horizon EURATOM EASI-SMR: Ensuring Assessment of Safety Innovations for SMR (2024–2028)

Kliem plays a central role in advising and leading collaborative research efforts, supervising junior researchers, and contributing to international benchmarking initiatives. He has no listed formal students, but his leadership implies significant mentoring. He is involved in multiple research facilities, including the ROCOM and TOPFLOW test facilities, which are critical for experimental validation of safety codes.

Laboratories and Facilities:

• ROCOM (Rossendorf Coolant Mixing) test facility – for studying coolant mixing and boron dilution
• TOPFLOW facility – for two-phase flow and safety experiments
• DYN3D/ATHLET code development and validation environment