Page 35 - Fundamentals of Magnetic Thermonuclear Reactor Design

18 Fundamentals of Magnetic Thermonuclear Reactor Design

TABLE 2.4 Parameters of Different ARIES FPPs
ARIES FPP version
Parameter I II IV AT
Plasma major radius (m) 6.75 5.2 5.6 5.2
Plasma minor radius (m) 1.5 1.3 1.4 1.3
Aspect ratio 4.5 4.0 4.0 4.0
Elongation of plasma column 1.8 1.8 1.8 ∼2.0
cross-section
Toroidal magnetic field on plasma 11.3 7.7 7.6 5.8
axis (T)
Toroidal magnetic field at coils (T) 21 16 16 12
Plasma current (MA) 10.0 5.3 5.6 12.8
Plasma toroidal beta (%) 1.9 3.4 3.5 9.0
Plasma additional heating power 200 ∼40 ∼40 40
(MW)
2
Neutron first wall load (MW/m ) 2.5 3.5 3.5 3.5

In addition to the necessity to increase unit size, transition from ITER to
DEMO places an even greater demand on the structural materials. Whereas
2
in ITER neutron fluence is within 0.3 MW·year/m , in DEMO it must reach
2
5 MW·year/m . Accordingly, radiation damages will increase from ∼3 dpa in
ITER to ∼50 dpa in DEMO and to 100–150 dpa in a commercial reactor.
Next comes ARIES [13–16], a series of the American ‘clean’ FPPs
(Table 2.4). The design electric power output of ARIES plants is 1 GW(e). The
distinction between different ARIES plants is that each subsequent project is
based on greater extrapolation in physics (very conservative in ARIES I and
getting on moving from ARIES II to ARIES IV more and more aggressive) and
simpler technical solutions.
The ARIES II and ARIES IV differ mainly in their structural materials, cool-
ant and tritium breeder (unlike ARIES II that uses vanadium as a structural ma-
terial and liquid lithium as a coolant, ARIES IV employs SiC, a helium coolant
and a Li O tritium breeder). The ARIES AT (advanced tokamak) is expected to
2
have a drastic increase in β with a considerable TF decrease in plasma and in
t
the coils (to 6 and 12 Т, respectively).
As one can see from Tables 2.3 and 2.4, the DEMO and FPP projects are ori-
ented towards higher physical parameters (β in the first place), than ITER, de-
t
termining the effectiveness of the TF coils – the most expensive reactor system.
That is why the ITER research programme aims at achieving plasma steady
state burning with enhanced confinement and non-inductive current drive.