RRFM 2009 Transactions - European Nuclear Society

for the U-8Mo fuel meat [5]. The power and flow diagrams, determining the regimes at
nominal operation in the LEU – core are given in Fig. 5 and Fig. 6. In Fig. 7 we compare the
power, heat flux and flow limits for the both HEU and LEU cores.
MCNPX
power peaking factors in outer fuel plate of BR2 fuel element
C259
Hot Channel Factors included
PLTEMP/ANL V3.6
Hot Channel Factors Not Included
1.5
ONB=1.0 (Bergles-Rohsenow)
ONB=1.0 (Forster-Greif)
FI (Whittle&Forgan)
ONB=1.0 (Bergles-Rohsenow)
ONB=1.0 (Forster-Greif)
FI (Whittle&Forgan)
15
Sieder-Tate
15
Dittus-Boelter
K V
1.0
0.5
HEU (standard)
UMo (8.5 g/cc) Cd=0.4mm
UMo (7.5 g/cc) Cd=0.4mm
UMo (8.5 g/cc) Cd=0.5mm
UMo (7.5 g/cc) Cd=0.5mm
-40 -20 0 20 40
axis Z [cm]
power [MW]
10
5
nominal operation
0
0 2 4 6 8 10 12 14 16 18 20
flow rate [m/s]
power [MW]
10
5
nominal operation
0
0 2 4 6 8 10 12 14 16 18 20
flow rate [m/s]
Fig. 1. Fig. 2.
heat flux [W/cm 2 ]
PLTEMP/ANL V3.6
Hot Channel Factors Included
Hot Channel Factors Not Included
ONB=1 (Bergles-Rohsenow)
ONB=1.0 (Bergles-Rohsenow)
ONB=1.0 (Forster-Greif)
ONB=1.0 (Forster-Greif)
FI (Whittle&Forgan)
FI (Whittle&Forgan)
FABREGA (Hot Channel Factors Included)
ONB=1 (Bergles-Rohsenow/Sieder-Tate)
ONB=1.0 (Forster-Greif/Sieder-Tate)
FI (Whittle&Forgan/Sieder-Tate)
nominal operation (SAR-BR2)
nominal operation (PLTEMP/ANL V3.6)
1600
1400
1200
1000
800
600
Sieder-Tate
Dittus-Boelter
400
400
200
nominal operation
nominal operation 200
0
0 2 4 6 8 10 12 14 16 18 20 0 2 4 6 8 10 12 14 16 18 20 0
flow rate [m/s]
flow rate [m/s]
1600
1400
1200
1000
800
600
heat flux [W/cm 2 ]
T onb
[° C]
220
210
200
190
180
Sieder-Tate
PLTEMP/ANL V3.6
Global and Local Hot Channel Factors Included
ONB=1.0 (Bergles-Rohsenow)
ONB=1.0 (Forster-Greif)
T sat
=183° C
Dittus-Boelter
170
0 100 200 300 400 500 600 700 800
200 400 600 800
maximum heat flux [W/cm 2 ]
maximum heat flux [W/cm 2 ]
220
210
200
190
T onb
[° C]
180
170
Fig. 3. Fig. 4.
Figure 1. Power peaking factors in the fuel plates of a standard BR2 fuel element calculated
with MCNP.
Figure 2. Power and flow limits in HEU – fuelled core, calculated by PLTEMP.
Figure 3. Heat flux and flow limits in HEU – fuelled core, calculated by PLTEMP.
Figure 4. Fuel-to-clad interface outer temperature vs. maximum heat flux in HEU – fuelled
core, calculated by PLTEMP.
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