40
3 Power Load on Plasma-Facing Materials
Steady
power load
Space plane protective plate
(one time use)
Fusion reactor
(Divertor)
Welder (Arc-jet)
Commercial nuclear
reactor
Boiler
(MW/m 2 )
0.01
0.1
1
10
100
1000
10000
Disruption in a fusion reactor
Transient
power load
ITER divertor structure
Wall load:
Radiation (heat)
High energy particles
Neutrons
Melting/evaporation
appears
~ 15-20 MW/m 2
~20 W/m2
Black body radiation
at 1000 C
Autocar radiator
Fig. 3.2 Comparison of surface power load in various energy systems
Hot pressing condition
- Temp. = 900 C
- Compression – 500 kgf
Braze condition
- Temp. = 850 C
- Bracing mater. = TiCuAg
ITER divertor structure
W armor tile
Brazing with
Cu+Ni plating
Heat sink
Cu alloy
Wall load:
Radiation (heat)
~ 15-20 MW/m 2
High energy particles
Neutrons
~20 W/m2
Swirl tube for
higher heat
removal
(b)
(a)
Fig. 3.3 Power load test for ITER divertor mockup with W hot pressed on a Cu alloy as a heat
sink with a swirl tube for cooling with different joining conditions. a Geometrical structure of the
mockup and b comparison of thermal response of W hot-pressing mockups with different joining
conditions in high-power flux experiments (reprinted with permission from [3])