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The paper presents results of SOLPS modelling of the edge plasma performance during the low-activation phase of ITER operation. The calculations show that the peak power loading of the divertor targets can reach the reactor-relevant level of 3 to 5 MW m−2, even without the fusion reactions, rendering commissioning of the high heat flux components possible in this phase. Parametrization of the output of the SOLPS runs for the predominantly helium plasma concerned by the studies reported here is performed, thus providing the boundary conditions for modelling of the core and allowing efficient integration of the core and edge models. This approach, using the ASTRA code for core simulations, is applied to the analysis of hydrogen accumulation in helium plasmas due to H pellet injection. The latter is the only available option for early testing of ELM pace-making as an ELM control tool assuming H-mode in hydrogen will not be possible. Critical dilution with H down to 70% He in the core plasma can be reached in only 0.5 to 1 s or even shorter, depending on the assumptions made. [ABSTRACT FROM AUTHOR]

The paper presents results of a first analysis of the divertor performance during the L–H transition in ITER. The integrated model consists of the SOLPS4.3 code suite for the SOL and divertor, and the ASTRA code for the core and pedestal regions. The results of SOLPS4.3 are parametrized and used as the boundary conditions for ASTRA, ensuring a consistent description of the plasma core and the edge. Boundary conditions switch from those for wide (L-mode) to narrow (H-mode) SOL once the transition criterion is met. The results show that, for conditions for which a full-power operational space with acceptable power loading of the targets exists, a transition from the initial L-mode operation to H-mode can be found for the same assumptions, i.e. the full-power H-mode regime is accessible. [ABSTRACT FROM AUTHOR]

Abstract: The effect of a hypothetical reduction of the SOL power width on the performance of the ITER divertor is analyzed using the SOLPS4.3 code. A reduction of this width by a factor 3 (down to 1.2mm) is found to increase the peak power load only by a factor 1.6 because power dissipation in the partially detached divertor plasma is enhanced. The operating window is smaller, but still exists at 10MW/m2 power load. Full alpha particle power is recovered if the allowed peak power load is a factor 1.5 higher, albeit at reduced Q which still remains above Q =10. [Copyright &y& Elsevier]