Fluid mixing and flow distribution in the reactor circuit (FLOMIX-R)
| Autor: | Rohde, U., Höhne, T., Kliem, S., Hemström, B., Scheuerer, M., Dury, T., Remis, J., Muhlbauer, P., Toth, I., Elter, J., Bezrukov, Y., Toppila, T., Lillington, J. |
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| Jazyk: | angličtina |
| Rok vydání: | 2005 |
| Předmět: | |
| Zdroj: | The 4-th International Conference "Safety Assurance of NPP with WWER", 23.-25.05.2005, Podolsk, Russia 4th Scientific and Technical Conference "Safety Assurance of NPP with WWER", 23.-26.05.2005, Podolsk, Russia |
| Popis: | The coolant mixing in PWR is an issue relevant for reactor safety, but of importance also for the optimisation of normal reactor operation. In the case of boron dilution accidents, the coolant mixing is the only effective mitigative mechanism against severe consequences of the accident. The degree of mixing determines the thermal and, therefore, mechanical load of the reactor pressure vessel wall. Within the European project FLOMIX-R, an unique experimental data base on coolant mixing in PWRs has been created. Experiments on coolant mixing have been performed at three European mixing test facilities representing different types of reactors. Additionally, slug mixing data from the FSUE EDO Gidropress VVER-1000 mock-up have been made available. Mixing under steady-state flow conditions, slug mixing during the start-up of the first main coolant pump and mixing of cold emergency core cooling (ECC) water have been investigated. Moreover, measurement data from a real VVER-440 reactor plant (NPP Paks in Hungary) have been made available. The measurement data base was used for the validation of computational fluid dynamics (CFD) codes. Calculations were performed for selected tests from the data base using the CFD codes CFX and FLUENT. For quality assurance in the CFD code validation, so-called Best Practice Guidelines (BPG) have been applied. The BPG require a minimization of numerical errors and solution errors by systematic grid and time step refinement and sensitivity tests on the impact of uncertainties in the boundary conditions, before the effect of different physical models can be assessed. The applicability of various turbulence modeling techniques was studied for transient and steady state flow. The paper gives on overview on the experimental data base and on first, preliminary conclusions from the CFD code validation. |
| Databáze: | OpenAIRE |
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