live‐ceram experiment: objectives and status of preparation
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KIT – University of the State of Baden-Württemberg andNational Large-scale Research Center of the Helmholtz Association
Institute for Nuclear and Energy Technologies
www.kit.edu
LIVE‐CERAM experiment: Objectives and status of preparation
A. Miassoedov, X. Gaus-Liu, J. Foit, T. Cron, T. Wenz, S. Schmidt-Stiefel
Karlsruhe Institute of Technology, Germany
17th QUENCH Workshop , KIT Germany, November 22-24, 2011 2
Outline
Objectives of LIVE-CERAM experiment
Difficulties in creating a 8 cm crust layer
Meeting of CEA and KIT and proposal of methods
Performance of three pre-tests (VV1, VV2 and VV3) for the formation of a refractory layer
Summary of the pre-tests
Ongoing activities
17th QUENCH Workshop , KIT Germany, November 22-24, 2011 3
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 temperature during ablation transient Evolution of melt pool temperature during ablation transient
17th QUENCH Workshop , KIT Germany, November 22-24, 2011 4
Expected Behaviour
The initial pure KNO3 layer acts as thermal barrier. The melt will heat up. The KNO3 material can be dissolved by the melt below the melting temperature of pure KNO3.
In the end state, the residual thickness of KNO3 will be compatible with conduction heat transfer and the final power dissipation. The melt will be enriched in KNO3.
The interface temperature between the melt and the residual KNO3 liner should, in the final steady state, reach the liquidus temperature of the actual, final, melt composition.
17th QUENCH Workshop , KIT Germany, November 22-24, 2011 5
LIVE 3D facility
vesse l coo ling
wall inner and outer therm ocouples
m elt pouring
cam era observation crust detection system
heating system
3D 1:5 scaled RPV of a typical German PWR
Surrounded by a cooling vessel to cool the test vessel by water or air
Volumetric heating system Central and non-central melt
pouring Measurements and Instrumentation
- Melt temperature: 60 thermocouples and crust detection lance
- Heat flux: 17 pairs wall temperature. - Crust growth: thermal couples trees in
the melt near the wall- Video cameras and infrared camera- Melt mass and crust mass: weighting
cells- Melt sampling
17th QUENCH Workshop , KIT Germany, November 22-24, 2011 6
Difficulties to generate refractory layer
A 8 cm KNO3 crust layer should be generated at the vessel wall.
8 heating elements
crust crust: 8 cm
crust profile in a volumetrically heated pool: thin and non-uniformly
desired crust profile in the LIVE-CERAM: thick and uniformly
17th QUENCH Workshop , KIT Germany, November 22-24, 2011 7
Solution: elevating the heating elements
Preferred methods: multi-step melt extraction or one-step melt extraction and heterogeneous heating
17th QUENCH Workshop , KIT Germany, November 22-24, 2011 8
Other agreements at the CEA/KIT meeting Geometries: height of refractory line: 435mm, height of ablation pool
385mm Measurements:
Evolution of melt pool temperature: 36 thermocouples Evolution of the interface temperature
Four thermocouple trees for crust temperature and interface temperature (new),
two positions for crust detection lance (new)
Initial ablation conditions: pouring temperature 260°C, maximum melt temperature 330°C, heating power 7kW in the liquid pool, vessel wall externally cooled by water
Steady-state criteria: steady melt temperature and crust temperature at polar angle 52° and 66°
17th QUENCH Workshop , KIT Germany, November 22-24, 2011 9
Pre-test 1 (VV1) : Multi-Step Melt Extraction
0 5000 10000 15000 20000 25000
0
2000
4000
6000
8000
100000 5000 10000 15000 20000 25000
100
150
200
250
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total power
tota
l hea
ting
pow
er [W
]
Time [s]
S1
cooling water flow out
S7
S6
S3S4
S5
S2
mass of melt
mas
s of
mel
t [kg
]
17th QUENCH Workshop , KIT Germany, November 22-24, 2011 10
Pre-test 1 (VV1) : Multi-Step Melt Extraction
0
20
40
60
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120
0 10 20 30 40 50 60 70 80 90
polar angle (°)
crus
t thi
ckne
ss (m
m)
azimuth 247.5°
azimuth 67.5°
gap
17th QUENCH Workshop , KIT Germany, November 22-24, 2011 11
Pretest 2 (VV2) : Smoothing the Crust of VV1 and Filling the Gap
Total heating power: 3300W at lower pool
Crust thickness: 6.5cm at top, maximum 14cm
VV1 profileVV2 profile
17th QUENCH Workshop , KIT Germany, November 22-24, 2011 12
Pretest 3 (VV3) : Heterogeneous Heating
Total heating power: 6200W, heterogeneous heating
Crust thickness: 6cm at top, 10cm at middle part and 11cm at bottom
VV3 profile
VV2 profile
17th QUENCH Workshop , KIT Germany, November 22-24, 2011 13
Summary of the Pre-tests The method of pre-test 3 (VV3) gives the best result. A gap is formed between crust and wall due to crust shrinkage
The gap has a width about 1cm. Most of the wall inner temperature thermocouples were destroyed during
crust shrinkage. The heat flux determination based on wall inner temperature will be not
exact. During ablation test, hot melt might penetrate through the crust to the gap
and fill in the gap, so that the local heat transfer condition afterwards will be changed.
By filling the gap before the ablation test can decrease the width of the gap, but not completely get rid of it.
The plug temperatures at the wall can be used instead of the wall inner temperatures for the heat flux determination.
17th QUENCH Workshop , KIT Germany, November 22-24, 2011 14
Ongoing Activities Instrumentation of 4 crust-temperature thermocouple trees,
totally 63 pieces, looking for the possibility of the second position for the
melt/crust boundary temperature measurement with crust detection lance,
Waiting for the reply from CEA about Confirmation of the method to create the refractory layer; Confirmation of the instrumentations; Opinion about the gap filling before the ablation test; Confirmation of the participation of the test and the date of the test
performance. The suitable date for KIT is November 28- December 09, 2011.
17th QUENCH Workshop , KIT Germany, November 22-24, 2011 15
Thanks for your attention
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