1. magnetic confinement - ENEA - Fusione

3. FUSION TECHNOLOGY 67
3.2 First Wall and Divertor
5 mm
Fig. 3.3 - Temperature distribution for RAE=10 MeV for 0.1s.
Fig. 3.2 - Normalised
energy density (GeV/cm 3 )
deposited by 10-MeV
RAE.
On the basis of the FLUKA outputs, the temperature pattern inside
the first-wall structures was defined with the use of the finiteelement
heat-conduction code ANSYS. The RAE energy deposition
density was assumed to be 50 MJ/m2, and both 10- and 100-µs
deposition times were considered. The temperature pattern just after
the RAE energy deposition, for an electron energy of 10 MeV and
energy deposition time of 0.1 s, is shown in figure 3.3 for geometry
1). The amount of armour material exceeding the melting
temperature is shaded grey in the figure.
The analysis demonstrated that for all the options but the Be flat-tile port limiter, the
heatsink and the cooling tube beneath the armour are well protected for both the
RAE energies and both the energy deposition times. However, there is a high degree
of melting (ablation) of the W (Be) surface layers, which would eventually affect the
PFC lifetime. As for the primary first wall with CFC poloidal limiters, the limiters
suffer severe ablation, the heat loads being six times larger than those in toroidally
uniform structures. As much as 15 mm of carbon per pulse is removed from the
limiter heads.
3.3 Vacuum Vessel and Shield
3.3.1. EM analyses of in-vessel components for ITER-FEAT
[3.3] EFDA Contract 00-
544, Design of the plasma
facing component (PFC)
for the divertor of ITER-
FEAT (2000)
[3.4] EFDA Contract 00-
570, EM analyses of
shielding blanket for
ITER-FEAT design
options, during plasma
disruptions (2000)
In ITER, the electromagnetic (EM) loads driven by plasma disruptions are one of the
most problematic issues for the in-vessel engineering. Considerable effort has been
spent on design analysis and R&D to obtain in-vessel components capable of
withstanding the EM loads induced by plasma disruptions. During 2001, extensive,
very detailed EM analyses were performed in support of this issue. For the support
to be really effective, the analyses had to have competing objectives: very accurate
component modelling, precision in describing the EM transient and, due to the very
large number of cases to be treated, very short computing time. The objectives were
achieved with the use of the zooming procedure developed at ENEA, which made it
possible to run the number of cases needed to select, for each component, the design
option with the best performance [3.3, 3.4].
The EM loads induced by the ITER reference plasma disruptions were evaluated for
the following in-vessel components: divertor, ICRH assembly, equatorial port limiter