Page 32 - Fundamentals of Magnetic Thermonuclear Reactor Design

Facilities With Magnetic Plasma Confinement Chapter | 2 15

The requirements imposed on a fusion reactor proceed from one technical
and economic characteristic – the reactor’s electric power. Based on the global
50 years of experience in nuclear power, it is logical to assess a fusion reactor’s
electric power as 1–1.5 GW – close to that of a standard nuclear power plant
unit. That is why a reasonable thermal power of a future FPP is around 3 GW.
General plant requirements include the limitation on the total consumption of
power drawn from the grid (P ≤ 500 MW), as well as on the weight of individu-
O
al modules (М ≤ 500 t). The limiting loads for electric grids and building cranes
1
were derived based on the ITER design data. For instance, the design deadweight
of a toroidal magnetic field coil module is 360 t; and that of a vacuum vessel with
radiation shielding provided on the inner surface is around 370 t. Similar require-
ments should perhaps be imposed on a commercial tokamak reactor.
In earlier reactor designs, the P and М values were much higher. For exam-
O
1
ple, the ITER engineering design activity phase (EDA) (before 1998) required
components moved by bridge cranes to be not heavier than 2 × 750 t.
The evolution of approaches to selecting plasma and electrophysical pa-
rameters of experimental tokamaks are summarised in Tables 2.1 and 2.2. The
earliest, T-20 tokamak [4], had a round cross-section plasma column, ‘warm’

TABLE 2.1 ITER Parameters at Different Project Phases [8–10]
Design stage
Parameter CDA (1990) EDA (1998) FEAT (2001)
Plasma major radius (m) 6.0 8.14 6.2
Plasma minor radius (m) 2.15 2.8 2.0
Aspect ratio 2.8 2.9 3.1
Elongation of plasma column 2.0 1.6 1.7
cross-section
Toroidal magnetic field on plasma 4.9 5.7 5.3
axis (T)
Plasma current (MA) 22 21 15
Stability margin 3.1 3.0 3.0
Plasma toroidal beta (%) 4.2 2.2 2.5
Plasma energy confinement time (s) 3.6 5.9 3.7
Average plasma temperature (keV) 10 13 10
20
−3
Average D–T ion density (10 m ) 1.2 1.0 1.0
Thermonuclear power (MW) 1000 1500 500
Plasma additional heating power (MW) 0 0 50
2
Neutron first wall load (MW/m ) 1.0 1.0 0.6
Burn time (s) 1000 1000 400