Impact of oxygen starvation on operation and potential gas-phase ignition of passive auto-catalytic recombiners

Meynet, N.; Boutarfaïa, Ahmed; Giovangigli, Vincent

doi:10.1016/j.combustflame.2014.02.001

Cited by 40 publications

(10 citation statements)

References 30 publications

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“…This, however, requires kinetics of all adsorption, surface and desorption reactions to be modelled when calculating the local hydrogen recombination rate, as in CFD simulations conducted by e.g. Meynet et al (2014).…”

Section: Resultsmentioning

confidence: 99%

“…Gera et al (2012), Heitsch (2000), Prabhudharwadkar et al (2011b), Reinecke et al (2010) and recently by Meynet et al (2014). Now it has reached a satisfactory level mostly in the case of stationary PAR operation.…”

Section: Introductionmentioning

confidence: 99%

“…In these conditions, components of the gas phase (nitrogen, oxygen, hydrogen and steam) are far from their critical point. Hence it could be assumed, following Reinecke et al (2010) and Meynet et al (2014), that density of the gas phase can be calculated from the ideal gas law. Other gas properties such as: thermal conductivity, dynamic viscosity and coefficients of molecular diffusivity were calculated in the present work from the kinetic theory of gas, while the specific heat of gas components was obtained from data available in the book of Poling et al (2001).…”

Section: Model Descriptionmentioning

confidence: 99%

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A Mechanistic Model of a Passive Autocatalytic Hydrogen Recombiner

Rożeń¹

2015

Chemical and Process Engineering

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A passive autocatalytic hydrogen recombiner (PAR) is a self-starting device, without operator action or external power input, installed in nuclear power plants to remove hydrogen from the containment building of a nuclear reactor. A new mechanistic model of PAR has been presented and validated by experimental data and results of Computational Fluid Dynamics (CFD) simulations. The model allows to quickly and accurately predict gas temperature and composition, catalyst temperature and hydrogen recombination rate. It is assumed in the model that an exothermic recombination reaction of hydrogen and oxygen proceeds at the catalyst surface only, while processes of heat and mass transport occur by assisted natural and forced convection in non-isothermal and laminar gas flow conditions in vertical channels between catalyst plates. The model accounts for heat radiation from a hot catalyst surface and has no adjustable parameters. It can be combined with an equation of chimney draft and become a useful engineering tool for selection and optimisation of catalytic recombiner geometry.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Model Descriptionmentioning

confidence: 99%

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A Mechanistic Model of a Passive Autocatalytic Hydrogen Recombiner

Rożeń¹

2015

Chemical and Process Engineering

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“…[3] and [5][6][7][8][9]. Gas fl ow inside PAR was modelled either as laminar [5,6,8] or as turbulent one using the k- model [7] and the k- model [3,9].…”

Section: Modelling Of a Passive Autocatalytic Hydrogen Recombiner -A mentioning

confidence: 99%

Modelling of a passive autocatalytic hydrogen recombiner – a parametric study

Rożeń

2015

Nukleonika

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Abstract. Operation of a passive autocatalytic hydrogen recombiner (PAR) has been investigated by means of computational fl uid dynamics methods (CFD). The recombiner is a self-active and self-adaptive device used to remove hydrogen from safety containments of light water nuclear reactors (LWR) by means of a highly exothermic reaction with oxygen at the surface of a platinum or palladium catalyst. Different turbulence models (k-, k-, intermittency, RSM) were applied in numerical simulations of: gas fl ow, heat and mass transport and chemical surface reactions occurring in PAR. Turbulence was found to improve mixing and mass transfer and increase hydrogen recombination rate for high gas fl ow rates. At low gas fl ow rates, simulation results converged to those obtained for the limiting case of laminar fl ow. The large eddy simulation technique (LES) was used to select the best RANS (Reynolds average stress) model. Comparison of simulation results obtained for two-and three-dimensional computational grids showed that heat and mass transfer occurring in PAR were virtually two-dimensional processes. The effect of hydrogen thermal diffusion was also discussed in the context of possible hydrogen ignition inside the recombiner.

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“…There are many studies to improve the performance of PAR. [3]- [6] However the technique takes an issue that PAR can be an igniter of hydrogen explosion instead of preventing when combustion occur in PAR. [7] In this study, a new shape of PAR structure is proposed, and analyzed to improve hydrogen reduction rates and reduce hydrogen explosion risk.…”

Section: Introductionmentioning

confidence: 99%

Effect of PAR Structure on Hydrogen Reduction Rate and Explosion Risk

Ryu¹,

Park

2016

Advanced Science and Technology Letters

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Abstract. Nuclear power plant is again concerned about a sever accident due to the Fukushima accident by hydrogen explosions. Hydrogen is produced by the reaction of the fuel rod coating material and water vapor in a very high ambient temperature, which condition is generated with the heat of the fuel. If the hydrogen is not removed sufficiently, that will be a principal cause of a hydrogen explosion. One of countermeasures to remove hydrogen is Passive Autocatalytic Recombiner (PAR). However, it was brought up that the spontaneous ignition on the hot surface inside the PAR could lead to hydrogen explosion. In this study a new design concept of the catalyst structure is proposed and analyzed. The results showed that the proposed structure of a catalyst reduced the hot temperature area which might reduce the hydrogen explosion risk.

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Impact of oxygen starvation on operation and potential gas-phase ignition of passive auto-catalytic recombiners

Cited by 40 publications

References 30 publications

A Mechanistic Model of a Passive Autocatalytic Hydrogen Recombiner

A Mechanistic Model of a Passive Autocatalytic Hydrogen Recombiner

Modelling of a passive autocatalytic hydrogen recombiner – a parametric study

Effect of PAR Structure on Hydrogen Reduction Rate and Explosion Risk

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