Analysis of the Boiling Water Reactor Turbine Trip Benchmark with the Code DYN3D


Analysis of the Boiling Water Reactor Turbine Trip Benchmark with the Code DYN3D

Grundmann, U.; Rohde, U.; (Editors)

Considering the phase 2 of the OECD/NRC BWR Turbine Trip Benchmark several analyses were performed with the help of the DYN3D code. Thermal-hydraulic boundary conditions of the core are given for this part of the benchmark. Concerning the modelling of the BWR in the DYN3D code several simplifications and their influence on the results were investigated. The standard calculations with DYN3D were performed with 764 coolant channels (1 channel per fuel assembly). It is shown that the power peak obtained for the given boundary conditions is close to the measured value. For numerical stability reasons, preliminary calculations were carried out neglecting the instationary mass balance equation. This approximation provided a stronger reduction of the core void that results in a higher power peak. The impact of the assembly discontinuity factors (ADF) was studied. It is shown that the influence on core-averaged values of the steady state and the transient is small. Considering local parameters the influence is not negligible. Several participants of the benchmark perform calculations with 33 thermal-hydraulic channels. The influence of the number of coolant channels has also a small effect on the core averaged values, but local parameters as axial power distribution in single fuel assemblies are affected. The phase slip model of MOLOCHNIKOV is the standard model of DYN3D for void fraction calculation. The ZUBER-FINDLAY model shows only small deviations from the standard case for both global and local values, however not in the direction of the measurement. Using the thermal-hydraulic boundary conditions the best agreement with the experiment was obtained for the standard model.

Keywords: nuclear reactors; transients; benchmarks; boiling water reactor; turbine trip; measurements; simulation; three-dimensional

  • Lecture (Conference)
    PHYSOR 2002 International Conference on the New Frontiers of Nuclear Technology: Reactor Physics, Safety and High-Performance Computing, October 7-10, 2002, Seoul, Korea
  • Contribution to proceedings
    PHYSOR 2002 International Conference on the New Frontiers of Nuclear Technology: Reactor Physics, Safety and High-Performance Computing, October 7-10, 2002, Seoul, Korea

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Publ.-Id: 4468