Overview of Containment Issues and Major Experimental ... · ERMSAR-2005 Session 3: CONTAINMENT...
Transcript of Overview of Containment Issues and Major Experimental ... · ERMSAR-2005 Session 3: CONTAINMENT...
ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Overview of Containment Issues and Major Experimental Activities
L. Meyer, H. Wilkening, H. Jacobs, H. Paillere
The first European Review Meeting on Severe Accident Research (ERMSAR-2005)
Aix-en-Provence, France, 14-16 November 2005
2ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Organization of the CONTAINMENT group(18 partner organisations)
WP12: Hydrogen Behaviour in Containment (HBC)WP 12-1: Hydrogen Combustion (HC)
WP 12-2: Containment Atmosphere Mixing (CAM)
WP13: Fast Interaction with Corium (FIC)WP 13-1: Fuel Coolant Interaction (FCI)
WP 13-2: Direct Containment Heating (DCH)
3ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Organization of the CONTAINMENT group
WP12: Hydrogen Behaviour in Containment (HBC)WP 12-1: Hydrogen Combustion (HC)
PARTNER (7) FACILITY CODEIRSN (France) ENACCEF TONUSFZJ (Germany) REKO-3 REKO-DIREKTFZK (Germany) COM-3DGRS (Germany) COCOSYS-DECORJRC (EU) REACFLOWTUS (Bulgaria) ASTECVEIKI (Hungary) GASFLOW
*CFD-codes*Lumped parameter codes
4ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Hydrogen Combustion
Topics of the EURSAFE PIRT addressed in WP 12-1: Hydrogen Combustion (HC)
Experimental Facility addressing the issue
Physical effect involved
REKO-3The use of recombiners might limit the explosion loads but could also cause ignition.
Hydrogen removal / mitigation
RUTScaling effects in hydrogen Combustion
Pressure loads
ENACCEFFlame Acceleration in non-uniform hydrogen/air/steam mixtures
Flame Propagation
5ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Hydrogen Combustion
The ENACCEF test facility (Enceinte d’ACCElération de Flamme)
The upper dome part with a total volume of 0.66 m3
The lower driver tube with a length of 3.2 m and a diameter of 0.154 m
6ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Hydrogen Combustion
ENACCEF test facility – experimental details
The ENACCEF test facility can be filled with any type of hydrogen-air-steam mixtures.
Within the acceleration tube obstacles can be installed to increase turbulent flame propagation/acceleration.
The facility is equipped with pressure transducers and photomultipliers.
The driver tube has also optical access to allow LDV and PIV measurements.
7ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Hydrogen Combustion / Removal
From the recombiner via the experiment to the model
outlet
catalystsheetsinlet
Box-type recombiner REKO-3 REKO-DIREKT
8ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Hydrogen Combustion / Removal
REKO-3 test facility
inlet
recombinerunit
catalyst sheets
outletgas analysis
9ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Hydrogen Combustion/Removal
REKO-3 - Measurements
INLET• flow rate• gas temperature• gas composition
OUTLET• gas temperature• gas composition CATALYST PLATE
• catalyst temperatureat 10 different locations
REACTION ZONE• gas compositionat 14 different locations
INLET PARAMETERS OF EXPERIMENTS- flow rate (0.25..0.80 m/s)- inlet temperature (ambient..150°C)- inlet hydrogen concentration
(0..5 vol.%, limited by safety concerns)- inlet steam concentration
(0..60 vol.%, depending on flow rate)- inlet oxygen concentration
10ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Hydrogen Combustion / Removal
REKO-3 experiments: transient measurements
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T = 25 °Cv = 0.5 m/s
yH2 = 4 vol.%
H2 + air
11ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Hydrogen Combustion / Removal
REKO-3 experiments: stationary behavior140
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12ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Hydrogen Combustion
Hydrogen explosion modeling with the CFD-code REACFLOW Advances in Grid Adaptation by Multiple Adaptation Variables
adaptation on the flame front(H2O concentration)
adaptation on the pressure wave ahead of the flame front
13ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Hydrogen Combustion
Case 1: single point ignition
Case 2: symmetric double point ignition
Studying different ignition scenarios for hydrogen combustion in a reactor using CFX and REACFLOW
With two ignition points the overall burning rate might be larger but flame speeds (overpressure) can be reduced due to shorter flame acceleration distances/time.
TEMPERATURE at 0.5 s 0.68 s 0.98 s
14ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Hydrogen Combustion
Investigating different venting scenarios using CFX and REACFLOW for a simplified nuclear reactor geometry
Modified venting could reduce quite drastically the pressure between neighboring rooms. Such different pressures could cause the collapse of the wall and trigger a sequence of events within the containment with potentially devastating effects.
15ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Hydrogen Combustion
ASTECTwo combustion options are already available : COVI, COMB in CPA
PROCO module is being implemented into CPA:
• All combustion modes from laminar deflagration to stable detonation are
covered
• Two criteria to decide about Deflagration-to-Detonation Transition:
- Mach number of precursor shock > 1.5 (composition dependent)
- Characteristic length of compartment > 7 times the detonation cell size λ (geometry and composition dependent)
16ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Organization of the CONTAINMENT group
WP12: Hydrogen Behaviour in Containment (HBC)WP 12-2: Containment Atmosphere Mixing (CAM)
PARTNER (12) FACILITY CODEIRSN (France) TOSQAN TONUS, ASTECCEA (France) MISTRA TONUSDIMNP (Italy) CONAN FLUENT, FUMO, MELCORFZK (Germany) GASFLOWGRS (Germany) COCOSYSJSI (Slovenia) CFX-4, CONTAIN, MELCORKTH (Sweden) CFX-4/5LEI (Lithuania) COCOSYS, ASTEC, CONTAINNRG (Netherlands) CFX-4/5, STAR-CD, SPECTRA, MAAPRUB-LEE(Germany) COCOSYSUPM (Spain) CFX-4, MELCORVEIKI (Hungary) GASFLOW, COCOSYS
17ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Containment Atmosphere Mixing
On-going R&D topics are related to identified gaps related to the formation of combustible gas mixtures in the containment, as identified in the EURSAFE PIRT or in recent benchmark exercises such as ISP-47:
Condensation modelling in CFD codes(UNIPI task leader)
- concerning diffusive models (wall function) or correlations (heat & mass transfer)
• review or in-depth analysis of past experiments (TOSQAN and MISTRA tests made available to SARNET)
• deficiencies, identification of validation needs
• recommendations on choice of models & best practice guidelines
• recommendations for new experiments (CONAN, MISTRA)
CONAN (UNIPI)
MISTRA (CEA)
Injection region (Zone 1) acceleration/decceleration and gas entrainment by the plume/jetInjection pipe
Non condensing wall
Condensing wall
Thermal free convection zone (Zone 4)thermally induced flow
Recirculation zone (Zone 2) recirculated flow induced by the jet
TOSQAN (IRSN)
18ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Containment Atmosphere Mixing
TOSQAN (IRSN)
On-going R&D topics are related to identified gaps related to the formation of combustible gas mixtures in the containment, as identified in the EURSAFE PIRT or in recent benchmark exercises such as ISP-47:
Spray modelling (IRSN task leader)
• Organisation of a benchmark Experiments performed by IRSN (TOSQAN) and CEA (MISTRA) are being provided as basis for benchmarking of LP and CFD codes – possibility to look at scaling effect: TOSQAN (7m3) MISTRA (100m3)
Effect of spray mitigation system on H2 distribution (risk):
- homogenization?- local H2 enrichment by steam condensation?
MISTRA (CEA)
19ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Containment Atmosphere Mixing
On-going R&D topics are related to identified gaps related to the formation of combustible gas mixtures in the containment, as identified in the EURSAFE PIRT or in recent benchmark exercises such as ISP-47:
Interaction PAR – atmosphere (CEA task leader)
• Organisation of a (numerical) benchmark on
interaction of Passive Autocatalytic Recombiners with containment atmosphere- issues of modelling (CFD) of thermal plume (burned gases)
- natural convection effects
- effect of positioning of recombiners in a room on global efficiency
20ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Organization of the CONTAINMENT group
WP13: Fast Interaction with Corium (FIC)WP 13-1: Fuel Coolant Interaction (FCI)
PARTNER (7) FACILITY CODEIRSN (France) TREPAM MC3DCEA (France) KROTOS MC3DFZK (Germany) ECO MATTINAIKE (Germany) DROPS IKEMIX, IDEMOJSI (Slovenia) ESE-2KTH (Sweden) MISTEE COMETA-KTHTUS (Bulgaria)
*CFD-codes
21ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Fuel-Coolant Interaction (FCI)
WP 13-1: Fuel-Coolant Interaction (FCI)
EURSAFE selected: FCI including steam explosion,in-vessel and ex-vessel.
Aim: - Increase knowledge about steam explosion energetics.- Develop tools to determine the risk of vessel or containment failure.
OECD Research program SERENA:- Aim: Evaluate capabilities of available codes with respect to
reactor applications.- Participants from SARNET: IRSN, CEA, FZK, IKE
22ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Experiment ECO (FZK):Measurement of Energy Conversion(mechanical energy release)Closed system of piston and cylinder15…18 kg of Al2O3 (in 4 tests)External trigger applied
• With full water mass, no explosion. • With restricted water mass (tube),
3 strong explosions.• Pressures well beyond 100 MPa.• Still quite low (and varying) energy
conversion: 2.4, 0.8 and 0.6 %.• Possible reasons for low conversion:
- high water subcooling (-> factor 2) - overstrong confinement
(piston mass = 2700 kg)• Facility mothballed
Fuel-Coolant Interaction (FCI)
23ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Fuel-Coolant Interaction (FCI)
Experiment KROTOS-Cadarache (CEA):
Study the effect of material properties on steam explosions.
Up to 5 kg corium of variable composition or 4 kg of SS (or 1.5 kg Al2O3).
External trigger applied.
Improvements with respect toKROTOS-Ispra:- reproducible melt release with slide valve;
- high-speed X-ray radioscopyto observe premixture.
To go in operation end of 2005.
24ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Organization of the CONTAINMENT group
WP13: Fast Interaction with Corium (FIC)WP 13-2: Direct Containment Heating (DCH)
PARTNER (7) FACILITY CODEIRSN (France) MC3D, RUPUICUV (ASTEC)EDF (France) MAAP-4FZK (Germany) DISCO-H/C AFDM, SIMMERGRS (Germany) CONTAIN, COCOSYSRUB-LEE (Germany)TUS (Bulgaria) ASTECFRA ANP (Germany)
*CFD-codes*Lumped parameter codes
25ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Direct Containment Heating (DCH)
HEAT TRANSFER CORIUM – STEAM / GAS
CONTAINMENT PRESSURIZATION
relocated corium
dispersed corium
steam blowdown
corium jet impact / fragmentation
+
breach in the lower head
H2 - COMBUSTION
metal oxidation and hydrogen production
trapped corium
corium film formation and entrainment
Phenomena occurring during DCH
26ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Direct Containment Heating (DCH)
PAST RESEARCH PROGRAMS (-1998)
Achievements • Large database on US reactor type plants.• Several analytical models were developed.• Simple models were integrated into codes
(MAAP, CONTAIN, MELCOR).
Main conclusions • Up to 70% dispersion out of pit• Containment integrity maintained• No scaling effect for pressure• Strong effect of geometry
Issue was closed for US plants
27ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Direct Containment Heating (DCH)
EURSAFE PIRT selected phenomena as most important:• corium entrainment out of reactor vessel with lateral breaches• corium oxidation coupled with hydrogen production• generating and trapping of particles• particle heat exchange• hydrogen combustion
Ø5092mm
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Ø5270mm
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GA 301
German KONVOI (similar to EPR) French 1300 MWe VVER-1000
28ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Nozzle
Annular gapRPV support
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RPV+RCS Volume
Filter
Gas Line
Steam Generator
Room
Pump Room
Rupture DiskMelt Simulant
Cavity
Test Facility DISCO-C (FZK)(EPR scale 1:18, P’4 scale 1:16)
Cold tests for fluid dynamic investigations
Simulant Melt: Water and liquid metal alloys Driving gas: Nitrogen and HeliumFailures Modes: Central and lateral breachesBurst pressure: 0.3 – 1.6 MPa
Central holes: Strong influence of initial gas pressure and hole size:
- The maximum dispersion (75%) is reached at pressures below 2 MPa
- Pressure < 0.5 MPa limits dispersion to <10% Lateral breaches and total circumferential breakaway of lower head lead to less dispersion than central holes
Direct Containment Heating (DCH)
29ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Test Facility DISCO-HH (FZK)(EPR scale 1:18, P’4 scale 1:16)
Hot tests including all processes, close to prototypical conditions:
Simulant Melt: Iron-alumina melt (2400 K)Driving gas: Steam or NitrogenFailures Modes: central breaches (3 sizes)Pressure at failure: 0.7 – 2.2 MPA
Containment atmosphere: Air + steam + H2 or N2
With or w/t direct flow path from pit to containment
Data available to SARNET partners from:6 Tests in EPR geometry1 Test in P’4 geometry (LACOMERA-1)1 Test in VVER-1000 geometry (LACOMERA-2)
Direct Containment Heating (DCH)
30ERMSAR-2005 Session 3: CONTAINMENT TOPICS
Test Facility DISCO-HH (FZK)(EPR scale 1:18, P’4 scale 1:16)
• Without hydrogen combustion pressure rise in containment is low.
• Pre-existing hydrogen content in containment can be important for pressure rise.
• Without direct flow path from pit to containment less hydrogen is burned and pressure rise is low.
• With small breaches the mixing and combustion of produced hydrogen with the containment atmosphere is too slow to contribute to peak pressure.
Investigations are necessary for each specific reactor design.
Direct Containment Heating (DCH)