Mitglied der Helmholtz-Gemeinschaft Simulation of the efficiency of hydrogen recombiners as safety devices Ernst-Arndt Reinecke, Stephan Kelm, Wilfried Jahn, Christian Jäkel, Hans-Josef Allelein International Conference on Hydrogen Safety September 12-14, 2011, San Francisco, CA

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 2E.-A. Reinecke et al. Overview Simulation of the efficiency of hydrogen recombiners as safety devices  Passive auto-catalytic recombiner (PAR)  Goal of the numerical study  Scenario investigated  Model approach  Results

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 3E.-A. Reinecke et al. Unintended H 2 release inside confined space safety measuredevice detectionsensor release interruptionautomatic valve avoid hydrogen accumulation and ignition/explosion ventilation recombiner

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 4E.-A. Reinecke et al. Passive auto-catalytic recombiner (PAR)

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 5E.-A. Reinecke et al. Commercial PARs in Nuclear Power Plants Vendors  AECL, Canada  AREVA, France/Germany  NIS, Germany Source: Siempelkamp

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 6E.-A. Reinecke et al. Operational boundary conditions NPP containment  large temperature and density gradients  large natural convection loops  large geometry (20,000-70,000 m³, typical length scales 5-50 m)  steam-inertized in early accident phase Typical H2 and FC applications  significant smaller scales  different thermal hydraulic conditions NPP PAR applicability ? H2 & FC GOAL:

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 7E.-A. Reinecke et al. Scenario

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 8E.-A. Reinecke et al. Source: CEA Experiment GARAGE facility at CEA/France  single vehicle private garage (~40 m³)  concentration measurement at ~60 pos. Test 1: He release (~2 g/s) for ~2 min data recently published: Gupta et al., Int J Hydrogen Energy 34 (2009) 5902–5911

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 9E.-A. Reinecke et al. Release scenario and measurement locations

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 10E.-A. Reinecke et al. Approach Scenario based on GARAGE experiment (CEA) 1.Simulation of the helium release and distribution scenario and validation against experimental data 2.Replace helium by hydrogen and verify the calculated distribution 3.Add a PAR to the scenario and compare mitigated/unmitigated scenario

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 11E.-A. Reinecke et al. Model approach

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 12E.-A. Reinecke et al. Coupled Modeling Approach Macro ScaleMeso ScaleMicro Scale REKO-DIREKT (in-house) ANSYS CFX

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 13E.-A. Reinecke et al. PAR model: REKO-DIREKT Input: T, y i, p Output: T, y i, mchemical (catalytical) reaction natural convection Chimney Catalyst section mass/heat transfer

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 14E.-A. Reinecke et al. T / °C y H2 / Vol.-% CFX  REKO-DIREKT - Inlet gas temperature - Inlet gas composition - Pressure REKO-DIREKT  CFX - Outlet gas temperature - Outlet gas composition - Mass flow through PAR REKO-DIREKT  CFX REKO-DIREKT

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 15E.-A. Reinecke et al. Results

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 16E.-A. Reinecke et al. Unmitigated release - setup Physical Model:  Half Symmetry  RANS equations  Ideal gas equation of state  Isothermal  SST-model incl. buoyancy prod. & dissipation  Injection He: 240 g (1,99 g/s) H2: 120 g (0,99 g/s)  Wall functions at inner walls  Vent: Outlet Boundary

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 17E.-A. Reinecke et al. Helium/Hydrogen concentration profiles

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 18E.-A. Reinecke et al. Mitigated release - setup Physical Model:  Half Symmetry  RANS equations  Ideal gas equation of state  SST-model incl. buoyancy prod. & dissipation  Injection H2: 120 g (0,99 g/s)  Wall functions at inner walls +Fixed Wall Temperature +Temperature dependent properties +No heat radiation  Vent: Outlet Boundary

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 19E.-A. Reinecke et al. Comparison mitigated/unmitigated scenario 800 s 240 s 120 s

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 20E.-A. Reinecke et al. Comparison mitigated/unmitigated scenario

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 21E.-A. Reinecke et al. Details mitigated scenario

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 22E.-A. Reinecke et al. PAR model details

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 23E.-A. Reinecke et al. Flammable cloud volume histories

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 24E.-A. Reinecke et al. Performance (estimates) Processor  1 CPU Quadcore I7-860, 2.8 GHz  Open Suse Linux 11.3  CFX 12.1 Calculation time (1200 s)  unmitigated scenario: ~10 d  mitigated scenario: ~40 d  REKO-DIREKT: ~6 min  more time steps  more gas components (H2+O2+N2+H2O)

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 25E.-A. Reinecke et al. Conclusions

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 26E.-A. Reinecke et al. Conclusions (1/2) Goal  investigate the applicability of PAR from NPP containment to typical H2&FC application  significant differences in operational boundary conditions  first study based on GARAGE experiment, performed with ANSYS- CFX and REKO-DIREKT Results  H 2 injection of 1.5 m³, flammable cloud was removed within 10 minutes  hot exhaust plume promotes the transport of hydrogen rich gas mixture towards the PAR inlet

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 27E.-A. Reinecke et al. Conclusions (2/2) Next steps  parameter variation  injection rate, location, and direction  PAR design and number  geometry of the enclosure  consideration of possible PAR ignition scenarios  validation against mitigation experiments in new multi-compartment facility, currently under construction at JÜLICH

ICHS-4 September 12-14, 2011, San Francisco, CA Folie 28E.-A. Reinecke et al. Thank you for your attention !