Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft X. Jin & L.V. Boccaccinislide # 1 PL...
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Transcript of Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft X. Jin & L.V. Boccaccinislide # 1 PL...
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
X. Jin & L.V. Boccaccini slide # 1
PL FUSION FZK - EURATOM ASSOCIATIONInstitut für Reaktorsicherheit
Status of accident analysis for HCPB
X. Jin, L.V. Boccaccini, R. Meyder
Garching, 9th Oct. 2006
Meeting on Safety assessment for EU TBM
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
X. Jin & L.V. Boccaccini slide # 2
PL FUSION FZK - EURATOM ASSOCIATIONInstitut für Reaktorsicherheit
PIE
HCS + CPS
TES
Pla
sma
Cha
mbe
r
Port Cell
TCWS vault
T Building
1. A double-ended pipe break in the TBM cooling loop in a large diameter pipe (ID=100mm) of the primary loop discharging coolant in the TCWS vault during plasma burn.
2. The coolant inventory is lost and the heat removal capability of the HCS goes to zero in short time.
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
X. Jin & L.V. Boccaccini slide # 3
PL FUSION FZK - EURATOM ASSOCIATIONInstitut für Reaktorsicherheit
Ex-vessel LOCA using RELAP5 MOD3.2
Double-ended pipe break in the TBM cooling loop in a large diameter pipe (DN100, Di=98.3mm, Da=114.3mm) during plasma burn (270KW/m²).
Recuperator
HX
Dust FilterCirculator
TB
M
8MPa
35°C
V3
T
T
V5
TB
M-B
ypas
s
Rec
-Byp
ass
50°C
500°C
300°C
V4
Heater II
E
T
V2
Heater I
E
Modeling gas compressor in RELAP5
V6
V7
PV He18MPa, 35°C
vlve702 Circ-Bypass
He0.1MPa, 20°C
vlve606
snglvol705
tmdpvol607
7.9MPa
p
Valve cross section:Vlve606 pipe break: 0.015178m² (=2*pipe area)Pressure vessel (PV) vlve 702: 0.0002513m²
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
X. Jin & L.V. Boccaccini slide # 4
PL FUSION FZK - EURATOM ASSOCIATIONInstitut für Reaktorsicherheit
Pressure results for ex-vessel LOCA
0.E+00
1.E+06
2.E+06
3.E+06
4.E+06
5.E+06
6.E+06
7.E+06
8.E+06
0 2 4 6 8 10 12 14 16 18 20
Time (s)
Pre
ssur
e (P
a)TBM inlet
• time constant 1.05s (p=2.96MPa)• at 2.4s p< 1MPa• at 10s p 0 (time for ramp of HTC in the next calculation)
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
X. Jin & L.V. Boccaccini slide # 5
PL FUSION FZK - EURATOM ASSOCIATIONInstitut für Reaktorsicherheit
Heat up of the FW (and TBM)
HCS + CPS
TES
Port Cell
TCWS vault
T BuildingHo
t sp
ot
500K
W/m
² 27
0KW
/m
²
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
X. Jin & L.V. Boccaccini slide # 6
PL FUSION FZK - EURATOM ASSOCIATIONInstitut für Reaktorsicherheit
Break of the FW
HCS + CPS
TES
Pla
sma
Cha
mbe
r Port Cell
TCWS vault
T Building
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
X. Jin & L.V. Boccaccini slide # 7
PL FUSION FZK - EURATOM ASSOCIATIONInstitut für Reaktorsicherheit
Case A
3. A trigger system able to shut down the plasma in 100s is assumed and doesn’t fail.
4. In this case, only the failure of the FW channels (now filled with a mixture of He/air at about 0.1 MPa) is considered as following failure; it opens a by pass from the TCWS to the VV with air penetration in VV. Be/air reaction at the FW surface occurs.
5. A loss of off-site power occurs, which is equivalent to a loss of heat sink in the TBM cooling system; it also means that the VV cooling system is in the natural convection mode.
6. After differential pressure inversion the gases (air, He) in the VV and in TBM flow towards outside through the TBM cooling loop bypass and tritium and dust can be transported from the gas stream and released in the external zones.
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
X. Jin & L.V. Boccaccini slide # 8
PL FUSION FZK - EURATOM ASSOCIATIONInstitut für Reaktorsicherheit
TBM-Model for study of temperature (air oxidation)Cut from EM_TBM (pol*tor*rad=740*1270*750)
Boundary conditions:• Surface heat flux 500/270KW/m²• FW cooling 330°C, 5000W/m²K• Cooling plate 450°C, 3000W/m²K• Radial power distribution• Radiation MF back side to 135°C• Radiation after plasma off from Be-
cover to blanket FW surface temperature*
• Radiation from BU back plate to MF3• Be reaction rate**• After heating power factor
* FIGURE VII.3.3.1-5 G84RI601-07-10 R1.0** G81RI1003-08-08W0.1
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
X. Jin & L.V. Boccaccini slide # 9
PL FUSION FZK - EURATOM ASSOCIATIONInstitut für Reaktorsicherheit
Case A/3,4,5
heat flux(KW/m²)
500
time
a (W/m²K)
5000
FW
0
0
I II III
I: initial position at steady state (4000s).II: loss of coolant in case of ex vessel LOCA, blow down within 10s (alfa=0, II-I=10s). III: plasma off, when Be melting point at 1290°C is reached (III-I=100s).IV: decay heating (IV-III=24h).
IV
Be+1/2O2 = BeO -610KJ/mol
4000s 10s100s
24h
(Other possibilities tbd)
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
X. Jin & L.V. Boccaccini slide # 10
PL FUSION FZK - EURATOM ASSOCIATIONInstitut für Reaktorsicherheit
Case A 100s delay (500KW/m²)
Be-cover
surfacePla
sm
a s
ide
interface
FW2 FW3 FW4 FW5 FW6
0 90 180 270 360 450Time (s)
Tem
per
atu
re (
°C)
1290
1057
824
591
358
125
100s
760
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
X. Jin & L.V. Boccaccini slide # 11
PL FUSION FZK - EURATOM ASSOCIATIONInstitut für Reaktorsicherheit
Case B
3. The detection of the ex-vessel LOCA fails to trigger the Fusion Power Shutdown System (FPSS); the plasma reaction runs until the beryllium cover of the first wall reaches 1290 °C. This is the melting temperature of beryllium and leads to inherent plasma shut down.
4. In this case it is assumed a complete failure of the FW integrity with penetration of air in the VV.
5. In addition it is assumed that a major plasma disruption is triggered by the entering air but without failure of water confinement in the shielding blanket or divertor system.
6. A loss of off-site power coincides with the disruption, which is equivalent to a loss of heat sink in the TBM cooling system; it also means that the VV cooling system is in the natural convection mode.
7. Box structures containing lithium orthosilicate and beryllium pebbles can loose their integrity. This means that air can enter the TBM box reacting with the Be pebbles.
8. After differential pressure inversion the gases (air, He) in the VV and in TBM flow towards outside through the TBM cooling loop bypass and tritium and dust can be transported from the gas stream and released in the external zones.
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
X. Jin & L.V. Boccaccini slide # 12
PL FUSION FZK - EURATOM ASSOCIATIONInstitut für Reaktorsicherheit
Case B/3,4,5,6,7
heat flux(KW/m²)
270
time
a (W/m²K)
5000
FW
0
0
I II III
I: initial position at steady state (4000s).II: loss of coolant in case of ex vessel LOCA, blow down within 10s (alfa=0, II-I=10s). III: plasma off, when Be melting point at 1290°C is reached (III-I=212s).IV: decay heating (IV-III=24h).
IV
Be+1/2O2 = BeO -610KJ/mol
4000s 10s212s
24h
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
X. Jin & L.V. Boccaccini slide # 13
PL FUSION FZK - EURATOM ASSOCIATIONInstitut für Reaktorsicherheit
Case B 212s delay to Be melting point (270Kw/m²)
Be-cover
surfacePla
sm
a s
ide
interface
FW2 FW3 FW4 FW5 FW6
0 90 180 270 360 450Time (s)
Tem
per
atu
re (
°C)
1290
1057
824
591
358
125
212s
896
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
X. Jin & L.V. Boccaccini slide # 14
PL FUSION FZK - EURATOM ASSOCIATIONInstitut für Reaktorsicherheit
Case B/7 0.1MPa air in pebble bed (“unrestricted air access” model)
Pebble bed temperatures, 24h after plasma offPebble bed temperatures, enlarged
Tem
per
atu
re (
°C)
980
856
732
608
484
360
0 4.8 9.6 14.4 19.2 24Time (h)
0 170 340 510 680 850Time (s)
1290
1090
890
690
490
290
Tem
per
atu
re (
°C)
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
X. Jin & L.V. Boccaccini slide # 15
PL FUSION FZK - EURATOM ASSOCIATIONInstitut für Reaktorsicherheit
Case C
5. In addition it is assumed that a major plasma disruption is triggered by the entering air with failure of water confinement in the shielding blanket or divertor system.
6. A loss of off-site power coincides with the disruption, which is equivalent to a loss of heat sink in the TBM cooling system; it also means that the VV cooling system is in the natural convection mode.
7. Box structures containing lithium orthosilicate and beryllium pebbles can loose their integrity. This means that a mixture of air/steam (tbd) can enter the TBM box reacting with the Be pebbles.
8. After differential pressure inversion the gases (air, steam) in the VV and in TBM flow towards outside through the TBM cooling loop bypass and tritium and dust can be transported from the gas stream and released in the external zones.
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
X. Jin & L.V. Boccaccini slide # 16
PL FUSION FZK - EURATOM ASSOCIATIONInstitut für Reaktorsicherheit
Case C Be/steam, assumption for ANSYS calculation
Be+H2O->BeO+H2-370KJ/mol
heat flux (KW/m²)
270
time
a (W/m²K)
5000
FW
0
0
I II III IV
4000s 1s10s
5h/96h
TBM pebble bed 0.2m³
Porosity por=0.67
steam diffuses into TBM pebble
bedpmax=60KPa, in=0.005mol/s
N mH2
Steam pressure in pebble bed p=nRT/[0.2*(1-por)], R=8.314J/molK
I: initial position at steady state (4000s).II: loss of coolant in case of ex vessel LOCA, plasma off within 1s (II-I=1s).III: blow down within 10s (alfa=0, III-I=10s). IV: decay heating (IV-II=96h).
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
X. Jin & L.V. Boccaccini slide # 17
PL FUSION FZK - EURATOM ASSOCIATIONInstitut für Reaktorsicherheit
Case C Be/steam reaction
172g H2 generated after 5h, extrapolation to 1day 825.6g H2, 4days 3.3Kg H2 (tbd).
H2 generation in pebble bed (steam)
0
20
40
60
80
100
120
140
160
180
0 1 2 3 4 5
Time (h)
H2
(g)
H2 generation at FW (steam)
0.00
0.05
0.10
0.15
0.20
0.25
0 1 2 3 4 5
Time (h)
H2
(g)
0.236g H2 generated after 5h, extrapolation to 1day 1.133g H2, 4days 4.53g H2 (tbd).
Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft
X. Jin & L.V. Boccaccini slide # 18
PL FUSION FZK - EURATOM ASSOCIATIONInstitut für Reaktorsicherheit
tbd
• Case A/3
ramp of power for plasma shut down in 100s?
• Case A/6, B/8
After differential pressure inversion the gases (air, He) in the VV and in TBM flow towards outside through the TBM cooling loop bypass and tritium and dust can be transported from the gas stream and released in the external zones.
• Case B/3
reference temperature uses EUROFER melting point instead of Be melting point?
• Case C/7-8
Box structures containing lithium orthosilicate and beryllium pebbles can loose their integrity. This means that a mixture of air/steam (tbd) can enter the TBM box reacting with the Be pebbles.
After differential pressure inversion the gases (air, steam) in the VV and in TBM flow towards outside through the TBM cooling loop bypass and tritium and dust can be transported from the gas stream and released in the external zones.