B. Bazylev1, G. Janeschitz2,
I. Landman1, G. Federici3, A.Loarte4, M.
Merola5, N. Klimov6, V. Podkovyrov6, A.
Zhitlukhin6, J. Linke7, J. Compan7, T. Hirai7
1Forschungszentrum
Karlsruhe, IHM, P.O. Box 3640, 76021 Karlsruhe, Germany
2Forschungszentrum Karlsruhe, Fusion, P.O. Box 3640, 76021 Karlsruhe,
Germany
3ITER JWS Garching Co-center, Boltzmannstr. 2, D-85748 Garching Germany
4EFDA-CSU,
Max-Planck-Institut für Plasmaphysik, D-85748 Garching, Germany
5EFDA-European
Fusion Development Agreement, D-85748 Garching, Germany
6SRC RF TRINITI, Troitsk, 142190,
Moscow Region, Russia
7Forschungszentrum
Jülich GmbH, EUROATOM-Association, D-52425 Jülich, Germany
Operation of ITER at high fusion gain is
assumed to be the H-mode. A characteristic feature of this regime is the
transient release of energy from the confined plasma onto plasma facing
components (PFCs) after multiple ELMs (about 104 ELMs per ITER
discharge), which can play a determining role in the erosion rate and lifetime
of these components. CFC and tungsten macrobrush armour are foreseen as PFC for
ITER divertor. During the intense transient events in ITER the evaporation
(CFC, W) and surface melting, melt motion, and melt splashing (W) are seen as
the main mechanisms of PFC erosion. Due to rather different heat conductivities
of CFC fibers a noticeable erosion of the PAN fibers may occur at a rather
small heat loads at which the damage to the tungsten armour is not substantial.
For the CFC and W macrobrush structure, the
results of erosion simulations after repetitive heat loads caused by ELMs like
heat loads with Q= 0.5-3.0 MJ/m2 and τ= 0.3-0.6 ms are presented and compared with
experiments at plasma guns. The target melt motion erosion of the W macrobrush
is calculated with the fluid dynamics code MEMOS in the ‘shallow water’
approximation, accounting for the surface tension and viscosity of molten metal
which have been extended to 3D geometry. The CFC armour erosion is calculated
by the 3-dimensional code PHEMOBRID-3D [1] in which 3D heat conductivity
properties of CFC are implemented. The numerical simulations are validated by
experiments done at QSPA facility (TRINITI). Erosion of CFC and W macrobrush
edges faced to the plasma stream under inclined heat loads is investigated.
[1] B.N. Bazylev et al. Physica Scripta, T111, (2004),
213-217.