Benchmark on Hydrogen Distribution in a Containment Based on the OECD-NEA THAI HM-2 Experiment

Schwarz, S.; Fischer, K.; Bentaib, A.; Burkhardt, Jörg; Lee, Jung-Jae; Duspiva, J.; Visser, D.C.; Kyttälä, Juha; Royl, P.; Kim, Jong-Tae; Kostka, P.; Liang, Rita

doi:10.13182/nt11-a12508

Cited by 32 publications

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“…Under-prediction of condensation can have different causes, for instance the implemented condensation model, the imposed initial conditions (gas composition and temperature distribution) and/or the modeled heat transfer to the solids. The influence of the heat losses to the solids for the THAI HM-2 test is also considered by Schwarz et al (2010) and Bentaib and Bleyer (2011). This heat transfer effect can be understood by observing the temperatures of the gas mixture in the vessel.…”

Section: Phase-1 Results (0-4300 S)mentioning

confidence: 99%

“…The international benchmark exercise ISP47 (Allelein et al, 2007) as well as the HM-2 benchmark exercise within the OECD-NEA THAI project (Schwarz et al, 2010) showed a strong user-dependence, which demonstrates the importance of setting up and applying best practice guidelines (BPGs) specific for containment applications. To make a start with the development of such BPGs, sensitivity analyses are performed in the present work to analyse the effect of mesh resolution, near-wall treatment, turbulence modeling and turbulence settings on the hydrogen distribution in a containment.…”

Section: Introductionmentioning

confidence: 99%

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Validation of a FLUENT CFD model for hydrogen distribution in a containment

Visser

Houkema

Siccama

et al. 2012

Nuclear Engineering and Design

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a b s t r a c tHydrogen may be released into the containment atmosphere of a nuclear power plant during a severe accident. Locally, high hydrogen concentrations may be reached that can possibly cause fast deflagration or even detonation and put the integrity of the containment at risk. The distribution and mixing of hydrogen is, therefore, an important safety issue for nuclear power plants.Computational fluid dynamics (CFD) codes can be applied to predict the hydrogen distribution in the containment within the course of a hypothetical severe accident and get an estimate of the local hydrogen concentration in the various zones of the containment. In this way the risk associated with the hydrogen safety issue can be determined, and safety related measurements and procedures could be assessed. In order to further validate the CFD containment model of NRG in the context of hydrogen distribution in the containment of a nuclear power plant, the HM-2 test performed in the German THAI (thermalhydraulics, hydrogen, aerosols and iodine) facility is selected. In the first phase of the HM-2 test a stratified hydrogen-rich light gas layer was established in the upper part of the THAI containment. In the second phase steam was injected at a lower position. This induced a rising plume that gradually dissolved the stratified hydrogen-rich layer from below. Phenomena that are expected in severe accidents, like natural convection, turbulent mixing, condensation, heat transfer and distribution in different compartments, are simulated in this hypothetical severe accident scenario.The hydrogen distribution and associated physical phenomena monitored during the HM-2 test are predicted well by the CFD containment model. Sensitivity analyses demonstrated that a mesh resolution of 45 mm in the bulk and 15 mm near the walls is sufficiently small to adequately model the hydrogen distribution and dissolution processes in the THAI HM-2 test. These analyses also showed that wall functions could be applied. Sensitivity analyses on the effect of the turbulence model and turbulence settings revealed that it is important to take the effect of buoyancy on the turbulent kinetic energy into account. When this effect of buoyancy is included, the results of the standard k-ε turbulence model and SST k-ω turbulence model are similar and agree well with experiment. The outcome of these sensitivity analyses can be used as input for setting up the guidelines on the application of CFD for containment issues.

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Section: Phase-1 Results (0-4300 S)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%