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Simulation of Scaled Core-Meltdown-Experiments and Investigation of a Possible Vessel Support against Failure

Willsch├╝tz, H.-G.; Altstadt, E.; Weiss, F.-P.; Sehgal, B. R.

At present the scaled core melt down experiments FOREVER are underway. These experiments are simulating the lower head of a reactor pressure vessel under the load of a melt pool with internal heat sources. Due to the multiaxial creep deformation of the three-dimensional vessel with a highly non-uniform temperature field these experiments are an excellent possibility to validate numerical creep models. A Finite Element model is developed and using the Computational Fluid Dynamic module the temperature field within the vessel wall is evaluated. The transient structural mechanical calculations are then performed applying a new creep model procedure. Additionally the material damage is evaluated considering the creep deformation as well as the prompt plasticity.
After post-test calculations for the FOREVER-C2 experiment, pre-test calculations for the experiments to come are performed. Taking into account both - experimental and numerical results - gives a good opportunity to improve the simulation and understanding of real accident scenarios. Analysing the calculations it seems to be advantageous to introduce a vessel support which can disburden the vessel from a part of the mechanical load and therefore avoid the vessel failure or at least prolongate the failure time as a possible accident mitigation strategy. Additionally, it seems to be possible to install an absolutely passive automatic control device to initiate the flooding of the reactor pit to ensure external vessel cooling in case of a core melt down.

Keywords: FOREVER-Experiment; Coupling of Thermo-Fluid Dynamic and Structural Mechanical FE-Model; Advanced Creep Modelling; Vessel Support as Accident Mitigation Strategy

  • Lecture (Conference)
    16th International Conference on Structural Mechanics in Reactor Technology SMiRT16, Washington, DC, USA, August 12-17, 2001, Paper No. 1145
  • Contribution to proceedings
    16th International Conference on Structural Mechanics in Reactor Technology SMiRT16, Washington, DC, USA, August 12-17, 2001, Paper No. 1145

Permalink: https://www.hzdr.de/publications/Publ-3832
Publ.-Id: 3832