Page 319 - Fundamentals of Magnetic Thermonuclear Reactor Design

Blanket Chapter | 10 299

In the final stage of the computational optimisation process, mechanical
stresses in the structure components are determined with due consideration
to their temperature and the liquid-metal static pressure and compared with
permissible stresses/pressures.
The number of iterations in the optimisation process may be decreased
establishing approximation dependencies between the tritium breeding rate/
radiation-induced heat release rate in the BZ and the radial coordinate. In this
case, the neutron calculations can be performed after a number of thermal hy-
draulic and MHD iterations.
After optimising the BZ geometry, verification analysis is performed. A 3D
model of 1/16 of the reactor (22.5 degrees of arc with 16 toroidal magnetic field
coils) with reflection boundary conditions (an monte carlo N-particle transport
code (MCNP) model adopted for ITER design with a neutron cross-section li-
brary) was used. It included the models of the IB and OB, the vacuum chamber
with three port belts, the divertor cassettes, the toroidal field coils and the cryo-
stat.
The MHD calculations are performed using commercial codes with MHD
modules (such as FLUENT and CFX) or specifically developed 2D and 3D
codes. They allow the pressure drop and velocity distribution over the cooling
channels’ cross-sections to be better defined with due consideration to factors,
such as gravity-induced thermal convection. The obtained results are used to
determine heat exchange coefficients at the wall/liquid metal interface needed
for heat transfer verification analysis. Commercial, predominantly 3D, codes
are used for strength analysis.

10.4 BLANKET DESIGNS FOR DEMONSTRATION
AND COMMERCIAL REACTORS
Blanket designs for demonstration and commercial fusion reactors can be di-
vided into Gen-1 (the 2020s–2030s) and prospective designs. Gen-1 blankets
utilise materials whose properties are comprehensively investigated, and which
are ready for pilot testing and commercial production. Prospective blankets re-
quire materials, which are yet to be developed and prepared for manufacturing
or be cleared for use in fusion reactors.

10.4.1 Gen-1 Blankets

Let us take a closer look into the structural features, parameters and charac-
teristics of the Gen-1 blankets (Table 10.2) [2–9]. These parameters as well as
data given in Tables 10.5 and 10.6 were collected by L.V. Boccaccini and C.P.C.
Wong with participation of the Test Blanket Group members and presented at the
8th International Symposium on Fusion Nuclear Technology, Heidelberg, Ger-
many, Sep. 30- Oct. 5, 2007. The first three columns contain data for the helium-
cooled ceramic breeder blanket, employed in the European Union (EU) HCPB,