Page 235 - Fundamentals of Magnetic Thermonuclear Reactor Design

216 Fundamentals of Magnetic Thermonuclear Reactor Design

upward process for the fusion industry. One cannot, for example, rule out the
revision of current concepts of energy absorption in favour of liquid-metal or
movable divertors (Section 7.4).
It is not only the first wall of a fusion machine that has to sustain severe heat
loads combined with other destructive impacts. Key functional components of
jet and rocket engines, electrical-ionisation lasers, nuclear reactors, magneto-
hydrodynamic (MHD) generators, powerful electrical vacuum devices, plasma
torches, and heat-to-electricity conversion plants are exposed to similar stresses.
For this reason, the closing subsection of this chapter addresses the alternative
uses of the first-wall technology.

7.2 FIRST-WALL DESIGN PRINCIPLES
7.2.1 Design Algorithm

In the course of their 60 years of evolution, the first-wall components were
getting more diverse and acquiring new functions. In the 1st-Gen tokamaks,
plasma is only separated from adjacent systems by the vacuum (discharge)
chamber wall, and there are stationary ring-shaped diaphragms inside the cham-
ber (Fig. 7.1). The diaphragms, following the shape of the plasma column, set
the confined plasma boundary. Ions emitted from that area and travelling along

FIGURE 7.1 1st-Gen tokamak structural scheme. 1 – vacuum (discharge) chamber; 2 – edge
plasma area; 3 – ring-shaped diaphragms; 4 – plasma column.