Experiments of the LACOMECO Project at KIT
A. MIASSOEDOV 1, M. KUZNETSOV 1, M. STEINBRÜCK 1, S. KUDRIAKOV 2
Z. HÓZER 3, I. KLJENAK 4, R. MEIGNEN 5, J.M. SEILER 6, A. TEODORCZYK 7
1 KIT,
Karlsruhe (DE)
4 JSI, Ljubljana (SI)
6 CEA, Grenoble (FR)
2 CEA,
3 AEKI, Budapest (HU)
Saclay (FR)
5 IRSN, Fontenay-aux-Roses (FR)
7 WUT, Warsaw (PL)
ERMSAR 2012, Cologne March 21 – 23, 2012
Background

Four KIT large-scale experimental facilities QUENCH, LIVE,
DISCO, and HYKA are offered to EU partners through the
Transnational Access to Large Research Infrastructures (TALI)
Project of the 7th EU FWP:
 1 experiment in QUENCH
 1 experiment in LIVE
 1 experiment in DISCO
 3 experiments in HYKA

Investigation of accident scenarios from core degradation to melt
formation and relocation in the vessel, melt dispersion to the
reactor cavity, and hydrogen related phenomena in severe
accidents

LACOMECO activities are strongly coupled to SARNET2
ERMSAR 2012, Cologne, Germany, March 21 – 23, 2012
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Selected LACOMECO experiments

QUENCH: QUENCH-16: Slow oxidation of fuel rod bundles in air
atmosphere (KFKI / AEKI, Budapest, Hungary together with INRNE
Sofia, Bulgaria)

LIVE: LIVE-CERAM: Dissolution kinetics of a pure KNO3 crust by a
KNO3/NaNO3 melt (CEA, Grenoble, France)

DISCO: DISCO-FCI: Ex-vessel fuel coolant interaction experiment in
the DISCO facility (IRSN, Fontenay-aux-Roses, France)

HYKA:
• UFPE: Upward flame propagation experiment in air-steamhydrogen atmosphere (JSI, Ljubljana, Slovenia)
• DETHYD: Detonations in partially confined layers of hydrogen-air
mixtures (WUT, Warsaw, Poland)
• HYGRADE: Hydrogen concentration gradients effects
understanding and modelling with data from experiments at HYKA
(CEA, Saclay, France)
ERMSAR 2012, Cologne, Germany, March 21 – 23, 2012
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QUENCH facility

Bundle with 21-31 fuel rod simulators
of ~2.5 m length

Electrically heated length: ~1 m;
max. power ~70 kW

Fuel simulated by ZrO2 pellets

Quenching (from the bottom)
with water or saturated steam

Gas analysis by mass
spectrometry (H2, steam …)

Fully instrumented to measure
T, p, flow rates, water level, etc.

Corner rods removable during tests
ERMSAR 2012, Cologne, Germany, March 21 – 23, 2012
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QUENCH-16 bundle test on air ingress
Consequences of possible air ingress into
overheated fuel assembly after damaging
of RPV or spent fuel container:
Objectives of the QUENCH-16 test
 acceleration in the cladding oxidation
•
•
 fuel rod degradation
 the release of some fission products,
most notable ruthenium
•
•
air oxidation after moderate preoxidation in
steam
slow transition in high temperature air with
following temperature excursion
role of nitrogen under oxygen-starved
conditions
hydrogen and nitrogen production during
reflood
Previous integral air ingress experiments:
 CODEX-AIT-1 and CODEX-AIT-2 tests
were performed at AEKI in 1998 and
1999 with small bundles
 QUENCH-10 performed 2004 at KIT:
strong pre-oxidised bundle
 PARAMETER SF4 performed 2009 at
LUCH/Podolsk: very high
temperatures on reflood initiation
ERMSAR 2012, Cologne, Germany, March 21 – 23, 2012
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QUENCH-16: gas consumption during air
ingress and gas release during reflood
reflood
N2 consumption
air ingress
O2 starvation
ERMSAR 2012, Cologne, Germany, March 21 – 23, 2012
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QUENCH-16 summary

Compared to QUENCH-10, the QUENCH-16 test was
performed with lower pre-oxidation, longer oxygen starvation
during air ingress and reflood initiation at lower temperatures

Maximal clad oxide thickness before air ingression 130 µm

Oxygen starvation duration 835 s on the end of air ingress

Temperature escalation from 1800 K to 2420 K upon reflood
initiation

Release of 24 g nitrogen during reflood compared to 29 g
consumed during oxygen starvation period

Significant hydrogen release during reflood: 128 g

Solidified partially oxidised melt between 300 and 500 mm,
relocated from upper elevations 500 – 800 mm
ERMSAR 2012, Cologne, Germany, March 21 – 23, 2012
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LIVE facility






1:5 scaled RPV, Ø1 m, wall thickness ~30 mm
cooling vessel to allow cooling by water or air
heating furnace of ~220 l volume
volumetric heating system
maximum temperatures of up to 1100 °C
central and non-central melt relocation
Pouring
spouts
Instrumentation





thermocouples
boundary layer temperature measurements
video (optical and IR) cameras
recording of the power input
extraction of melt sample
ERMSAR 2012, Cologne, Germany, March 21 – 23, 2012
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Background and objectives of
LIVE-CERAM experiment
Background

Design of refractory liners for core catchers and for protection of concrete walls
(applications for LWRs and for LMFBRs).

Development of model calculations for corium – refractory material interaction

Few data on corium-refractory material interaction

No detailed transient data available for the corium-refractory material interaction for
2D geometry
The objective is to simulate ablation process of a high-melting
temperature refractory material by low-melting temperature corium

KNO3 as refractory material (melting temperature ~334 °C) and a KNO3+NaNO3
melt at, initially, the eutectic composition (melting temperature ~220 °C) as corium

Provide data for transient corium-refractory material interaction
–
Evolution of boundary layer temperature during ablation transient
–
Evolution of melt pool temperature during ablation transient
ERMSAR 2012, Cologne, Germany, March 21 – 23, 2012
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Crust thickness profile evolution
in LIVE-CERAM
8 cm thick KNO3 refractory wall
was created by
Crust thickness, mm
before ablation
120
Ablation 1, 7 kW
100
Ablation 2, 15 kW
80
60
40
20
0
0
10
20
30
40
50
Polar angle, °
60
70
80
lifting the heating coils 63 mm

higher power density in the
lower part of the vessel
Ablation phase 1: 7 kW
 dissolved KNO3: 39 kg
 KNO3 in melt:
– original melt: 51%
– final melt: 60%
160
140

90
Ablation phase 2: 15 kW
 dissolved KNO3: 24 kg
 KNO3 in melt:
– original melt: 58.2%
– final melt: 62%
ERMSAR 2012, Cologne, Germany, March 21 – 23, 2012
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LIVE-CERAM: progression of melt
temperatures and interface temperatures
Ablation phase 1
Ablation phase 2
max. melt temp
340
340
max. melt temp
320
Interface temp
Temperature, °C
Temperature, °C
320
300
280
260
300
280
260
240
240
220
220
200
200
0
20000
40000
60000
80000
100000
Interface temp
120000
0
20000
Time, s
ERMSAR 2012, Cologne, Germany, March 21 – 23, 2012
40000
60000
80000
100000
Time, s
11
120000
DISCO-FCI background and objectives

Experiment similar to those made for DCH, but with water in the pit
 data for the validation of the codes in geometrical situation
closer to the reactor ones than all other available data
–

Bridges the gap between DCH and ex-vessel FCI issues
Valuable information for several SARNET2 WPs
–
Melt fragmentation processes for high velocity melt jets obtained by a precise
analysis of the size of the debris found (WP7.1, WP5.3)
–
Pressurization of the pit and containment during the mixing (WP7.1)
–
Debris bed characteristics important for coolability:
shape, porosity, debris size distribution (WP5.3)
–
Melt and water dispersion out of the pit during the process:
initial conditions for MCCI (WP6)
–
Oxidation of the iron to be compared with cases without water:
impact of water on DCH (WP7.1)
–
Hydrogen production and potential impact of water for combustion (WP7.2)
ERMSAR 2012, Cologne, Germany, March 21 – 23, 2012
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Design of the DISCO-FCI experiment
Vmelt = 0.0026 m³
Vwater = 0.125 m³
Vw/Vm
ERMSAR 2012, Cologne, Germany, March 21 – 23, 2012
= 48
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DISCO-FCI: Main results
Particle size distribution
Pressures in the cavity
Containment temperatures
MC3D analysis at IRSN
ERMSAR 2012, Cologne, Germany, March 21 – 23, 2012
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HYKA facilities for hydrogen research


A3
Analysis of H2 distribution and
combustion processes in severe
PWR accidents and BWR
incidents
Provision of an adequate scientific
basis for reliable hydrogen risk
reduction in NPPs
A1
Parameters of the test vessels
 A1: 110 m3, 100 bar
 A3: 30 m3, 60 bar
 A6: 23 m3, 40 bar
ERMSAR 2012, Cologne, Germany, March 21 – 23, 2012
A6
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UFPE: Upward flame propagation experiment
in hydrogen-air-steam atmosphere
Objectives: Scaling of H2 combustion in NPP containments for code validations
Method:
To compare dynamics of the combustion process with similar THAI tests
Objects for scaling:
PWR  HYKA-A2  THAI
Blind numerical calculations will be performed within SARNET2
Volume: 125000 m3 (SF=2100)
Diameter: 50 m
(SF=16)
Height:
63 m
(SF=7)
H/D:
1.3
PWR
220 m3 (SF=3.7)
6m
(SF=1.9)
9.1 m (SF=1)
1.5
HYKA-A2
ERMSAR 2012, Cologne, Germany, March 21 – 23, 2012
60 m3 (SF=1)
3.2 m (SF=1) Scaling Factor (SF)
9 m (SF=1)
2.8 Aspect Ratio
THAI
16
UFPE: Upward flame propagation experiment
in hydrogen-air-steam atmosphere
Initial conditions: pressure
temperature
steam concentration
hydrogen concentration
p = 1.5 bar
t = 90 oC
25 vol. %
10 vol. %
Integral characteristics to be compared:
Max. pressure:
pmax = 5 bar
Max. temperature:
tmax = 900 oC
Time of combustion:
tc = 4.5 s
THAI
hidden before blind
???
calculations will be finished
???
???
HYKA-A2
Scientific questions:
(1) if two experiments are performed in similar
facilities of different volumes, with similar experimental conditions, what are the
observed qualitative and quantitative differences?
(2) how can experimental results obtained in
scaled-down experimental facilities be extrapolated to NPP containments
ERMSAR 2012, Cologne, Germany, March 21 – 23, 2012
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HYGRADE: Hydrogen concentration
gradients effects
Objectives: (1) Flame acceleration and quenching experiments with concentration
gradients in obstructed geometry in large scale offered by HYKA-A3 vessel
(2) To provide high quality experimental data on overpressures and flame
propagation velocities required for numerical code validations
Method:
to register dynamics of the combustion process, to measure energy
(heat) losses (by pressure measurements)
Facility:
HYKA-A3 (V=33 m3, H=8 m, D=2.35 m)
Ignition
A3 vessel
Internal obstacles
ERMSAR 2012, Cologne, Germany, March 21 – 23, 2012
Hydrogen injection systen
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HYGRADE: Hydrogen concentration
gradients effects
Current state: (1) Ten combustion experiments were performed
(2) Data processing is in progress
(3) Numerical simulations to be started
Main results: (1) Hydrogen distribution experiments were performed in order to create a
relatively stable vertical hydrogen concentration gradients from 4 to 13%H2 and from 13 to 4% H2
(2) Flame propagation experiments for upper and lower ignitions with positive and
negative hydrogen concentration gradients showed that no quenching phenomena in large scale
occurred
H2-concentration gradients
Pressure and temperature records
09.01.2012 + 10.01.2012H2
7000
6000
h / mm
5000
4000
3000
2000
positive
1000
0
4
5
6
7
8
9
10
11
12
13
H2+13.01.2012
/%
12.01.2012 (2)
H2
7000
6000
h / mm
5000
h, m
7.5
7
6.5
6
5.5
5
4.5
4
3.5
3
negative gradient 12 – 6 %
Flame
trajectory
2.5
4000
2
1.5
3000
2000
negative
1000
0
4
5
6
7
8
9
10
11
12
13
Ignition
1
0.5
t, s
H2 / %
ERMSAR 2012, Cologne, Germany, March 21 – 23, 2012
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DETHYD: Detonation in partially confined
layers of hydrogen-air mixtures
Objectives: To find experimentally the critical conditions for DDT and detonation
propagation in partially confined layers of hydrogen-air mixtures
To provide high quality experimental data on overpressures and flame
propagation velocities required for numerical code validations
Method:
To register dynamics of the detonation process, records of soot tracks (l),
max. pressure (PCJ)
Facility:
HYKA-A1 (V=100 m3, L=12 m, D=3.3 m) in a box of 9x3x0.6 m
Experimental set-up:
Test layer 30 cm
Uniform mixture (30%H2-air)
Stratified mixtures (20-35%H2 at the top and 0- 4%H2 in
air at the bottom)
ERMSAR 2012, Cologne, Germany, March 21 – 23, 2012
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DETHYD: Detonation in partially confined
layers of hydrogen-air mixtures
Current state: (1) Ten detonation experiments are performed
(2) Data processing is completed and report is issued
Main results: The critical layer thickness for detonation propagation in a semi-open, uniform,
stoichiometric hydrogen-air mixture is greater than approximately h* > 3 cm. This critical value
corresponds to the ratio do detonation cell size λ as h* ≈ 3λ.
The critical hydrogen concentration for steady-state detonation propagation in a
stratified layer of H2-air mixture was measured of about 16.6 %. It also requires h*=8.5-14 cm of
layer thickness or ~3-4 detonation cells across the layer.
High speed movie
Pressure-time history
H2-concentration gradient
Maximum pressure vs. distance
60
Maxim um hydrogen concentration
31%H2
Overpressure D p [bar]
50
27%H2
26%H2
25%H2
40
30
20
10
0
Detonation
cell
structure
Uniform mixture (30%H2-air)
0
2
4
6
8
x [m] 10
Detonation cell structure
Stratified mixtures (20-35%H2 at the top and 0- 4%H2 in
air at the bottom)
ERMSAR 2012, Cologne, Germany, March 21 – 23, 2012
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Acknowledgements
The authors gratefully acknowledge funding
by Euratom to support the work within
LACOMECO project
ERMSAR 2012, Cologne, Germany, March 21 – 23, 2012
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… and finally
Thank you for your attention!
ERMSAR 2012, Cologne, Germany, March 21 – 23, 2012
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