Dr. Sören Kliem

Reactor Safety
Phone: +49 351 260 2318

Department of Reactor Safety


Neutron physics and reactor dynamics

  • Validation and application to light water reactors and innovative reactor concepts of the Monte Carlo code SERPENT2
  • Application of the deterministic lattice code HELIOS-2
  • Development, verification and application of the in-house reactor dynamics code DYN3D
  • Extension of the DYN3D code to innovative reactor concepts
  • Coupling of DYN3D to the system code ATHLET
  • Coupling of DYN3D to the Computational Fluid Dynamics codes ANSYS CFX and TRIO_U

Plant dynamics and severe accident analysis

  • Accident analysis and analysis of plant dynamics using the ATHLET system code
  • Assessment of the impact of severe accident management measures on the progression of severe accidents in PWRs and VVERs

Monte-Carlo simulations (n- / γ-field calculations)

  • Development of the in house Monte Carlo code TRAMO
  • Fluence calculations of the of the reactor pressure vessel and internals using MCNP and TRAMO

Latest Publication

Extension of the DYN3D/ATHLET code system to SFR applications: models description and initial validation

Fridman, E.; Nikitin, E.; Ponomarev, A.; Di Nora, A.; Kliem, S.; Mikityuk, K.

The coupled DYN3D/ATHLET code system was recently adapted for Sodium cooled Fast Reactors (SFRs) applications. The main objective of this study is to validate further the DYN3D/ATHLET code system by performing a coupled 3D neutron kinetics/thermal-hydraulics analysis of six transient start-up tests conducted at the French Superphenix (SPX) reactor. The tests were a part of the startup test program aiming at evaluation of the core reactivity feedback characteristics. Peculiarity of these transients is the necessity of accounting for the thermal expansions of the primary system structural elements influencing the position of control rods in the core.
The paper includes a brief summary on the benchmark specification, description of the neutronics and thermal-hydraulics models, and comparison of the simulation results to the available experimental data. For all six transients, a good agreement between simulations and experiments was observed confirming a reasonable performance of DYN3D/ATHLET.

Keywords: Serpent; Monte Carlo; DYN3D; ATHLET; Coupled code system; SFR; Superphenix


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FWOR Jörg Konheiser Evgeny Nikitin André Gommlich Dr. Alexander Grahn Reuven Rachamin Dr. Silvio Baier Kerstin Kurde Dr. Emil Fridman Dr. Frank Schäfer Dr. Sören Kliem


NameBld./Office+49 351 260Email
Dr. Sören Kliem250/1082318


NameBld./Office+49 351 260Email
Dr. Silvio Baier250/1113034
Dr. Yurii Bilodid250/2092020
Dr. Emil Fridman250/2092167
Matthias Jobst250/1143572
Jörg Konheiser250/1092416
Kerstin Kurde250/1073025
Dr. Evgeny Nikitin250/2072906
Dr. Erik Pönitz250/1152067
Dr. Reuven Rachamin250/1103291
Dr. Frank Schäfer250/1172069


Dr. Sören Kliem

Reactor Safety
Phone: +49 351 260 2318