Simulations of ITER start-up and assessment of limiter power loads

This paper presents the results of a modelling study conducted to estimate the power crossing the separatrix (PSOL) in the ITER device during a standard start-up sequence. This is used to calculate the power intercepted by the start-up limiters and the resulting power load distribution. The models and methodologies applied to calculate PSOL and the power loads on the limiters are described in detail elsewhere ([e.g., M. Kobayashi et al., Nucl. Fusion. 47 (2) (2007) 61]) and only a brief mention of some of the main results is included here. These assessments show that for the range of conditions analysed, the maximum PSOL intercepted by the two ITER limiter start-up modules during the current ramp-phase is ∼6 MW. The peak power load to each limiter is calculated to be ∼5 MW/m2, but these values depends on assumptions on physical quantities (e.g., transport coefficients, i.e., D⊥ and χ⊥), which are uncertain and still await confirmation by experiments. Recommendations are made for modelling and experiments to extend the study presented here.