ermsar 2012, cologne march 21 – 23, 2012 experimental determination and analysis of iodine mass...
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ERMSAR 2012, Cologne March 21 – 23, 2012
Experimental Determination and Analysis of Iodine Mass Transfer Coefficients from THAI Test Iod-23
K. FISCHER, Becker Technologies GmbH, Eschborn (GE)
G. WEBER, GRS, Garching (GE)
F. FUNKE, G. LANGROCK, AREVA GmbH, Erlangen (GE)
ERMSAR 2012, Cologne March 21 – 23, 2012
THAI vessel with general thermal hydraulic instrumentation
ERMSAR 2012, Cologne March 21 – 23, 2012Configuration of THAI facility for I2 mass transfer test
(including target values of boundary conditions)
ERMSAR 2012, Cologne March 21 – 23, 2012
Air injection port
ERMSAR 2012, Cologne March 21 – 23, 2012Test intervals of stagnant and moving sump water flow
0
2
4
6
8
10
12
14
-1 0 1 2 3 4 5 6 7 8 9 10 11 12
Time (h)
Wat
er r
ecir
cula
tio
n f
low
Iodine injection
Sump recirculation off
Sump recirculation on
ERMSAR 2012, Cologne March 21 – 23, 2012Iodine mass flow from water surface to air space
0
0
0
0
0 2 4 6 8 10
Time (h)
Iod
ine
ma
ss
flo
w (
log
ari
thm
ic s
ca
le).
OD
CF
Model
ERMSAR 2012, Cologne March 21 – 23, 2012
Iodine mass flux from the water surface to the gas space:
w2
1
ggw
ww
w
g2g I/Gkk
P/Gk
k
1
t
I
A
V
w2cw2
w
w Ikt
I
A
V
Conversion of dissolved I2 to iodide ions I- by surface reaction with submerged steel:
Water-side mass transfer coefficient based on unsteady molecular diffusion:
cw t
Dk
ERMSAR 2012, Cologne March 21 – 23, 2012
Average contact time tc for constant radial flow velocity v = 0.35 m/s
v3
Rdrr2
v
rR
R
1t
R
02c
tc (s) kw (m/s) s (m)
Stagnating sump < 7200 > 3.5E-7 <0.0025
Mixed sump 0.67 3.6E-5 2.4E-5
AIM-3 default - 1E-5 -
Results for contact time, transfer coefficient and film thickness s
ERMSAR 2012, Cologne March 21 – 23, 2012
ERMSAR 2012, Cologne March 21 – 23, 2012Model comparison for iodine mass flow
0
0
0
0
0 2 4 6 8 10
Time (h)
Iod
ine
ma
ss
flo
w (
log
ari
thm
ic s
ca
le).
OD
CF
Model
ERMSAR 2012, Cologne March 21 – 23, 2012
Uncertainties of the present analysis:
• Experimental uncertainties (no explicit measurement of I2w; reduction of I2w by reaction with steel wall; determination of tc; influence of air flow upon surface exchange during stagnation conditions)• Model simplifications (e.g. uniform boundary layer thickness; uniform contact time)
Conclusion:
Validity of the film renewal model is well confirmed within the error margins of the present experimental data
ERMSAR 2012, Cologne March 21 – 23, 2012
Film renewal model or penetration theory
Water
Atmosphere
Bulk iodine concentration c1
Interface concentration c1i
Concentration boundary layer
cw t
Dk
ERMSAR 2012, Cologne March 21 – 23, 2012
How to determine the contact time tc?
From scaling consideration: tc ~ surface length/velocity
From 3-d pool flow simulation: 2-d flow distribution in surface fluid layer with sources and sinks; calculate average surface fluid age
a = age = contact time tc, q = areal flow source/sink (1/s), A = age of source/sink flow (source A = 0, sink A = a)
1)aA(qaut
a