VVER-1000 main steam line break analysis using the coupled code system DYN3D/ATHLET


VVER-1000 main steam line break analysis using the coupled code system DYN3D/ATHLET

Kliem, S.; Kozmenkov, Y.; Höhne, T.; Rohde, U.; Weiß, F.-P.

Calculations using the coupled code system DYN3D/ATHLET were performed in the frame of the OECD/NEA MSLB benchmark for a VVER-1000 reactor. The coolant mixing inside the reactor pressure vessel was treated using a validated empirical mixing model implemented into the DYN3D/ATHLET code.
Using very conservative boundary conditions (reduced scram worth, two stuck rods, running MCP throughout the whole transient) a return-to-power was predicted.
For the assessment of the empirical mixing model a time dependent calculation using the computational fluid dynamics code CFX-10 was performed. For that analysis, a detailed model of the reactor pressure vessel consisting of the inlets nozzles, downcomer, lower plenum and a part of the core and having 4.67 million unstructured tetra cell elements was used. For the considered case with running main coolant pumps, this calculation shows a sector formation at the core inlet with a certain amount of mixing at the edges of the sector.
A core calculation using these CFX results as boundary conditions predicted also a return-to-power with a maximum value being about 200 MW lower than in the coupled code calculation. This variation calculation confirms the applicability of the empirical mixing model. The comparison shows also, that in this way results with a reasonable degree of conservatism can be obtained.

  • Contribution to proceedings
    International Conference on the Physics of Reactors (PHYSOR'08), 14.-19.09.2008, Interlaken, Switzerland
    Proceeedings of the International Conference on the Physics of Reactors 2008, CDROM paper 311, Villigen: Paul Scherrer Institut, 978-3952140956
  • Lecture (Conference)
    International Conference on the Physics of Reactors (PHYSOR'08), 14.-19.09.2008, Interlaken, Switzerland

Permalink: https://www.hzdr.de/publications/Publ-11279
Publ.-Id: 11279