Analysis of fuelling requirements in ITER H-modes with SOLPS-EPED1 derived scalings

Abstract

Fuelling requirements for ITER are analysed in relation to pellet fuelling and ELM pacing, and a divertor power load control consistent with the ITER pumping and fuel throughput capabilities. The plasma parameters at the separatrix and the particle sources are derived from scalings based on SOLPS simulations. Effective transport coefficients in the H-mode pedestal are derived from EPED1 + SOLPS scalings for the pedestal height and width. 1.5D transport is simulated in the ASTRA framework. The operating window for ITER DT plasmas with the required fusion performance and level of ELM, and divertor power load control compatible with ITER fuelling and pumping capabilities, is determined. It is shown that the flexibility of the ITER fuelling systems, comprising pellet and gas injection systems, enables operation with Q = 10, which was found to be marginal in previous studies following a similar approach but with different assumptions. The present assessment shows that a reduction of 〈 n e 〉 by a factor ~2 (from 9 to 5 × 1019 m−3) in 15 MA H-mode plasmas leads to a reduction in the required pellet fuelling rate by a factor of four. Results of the analysis of the fuelling requirements for a range of ITER scenarios are found to be similar to those obtained with the JINTRAC code that included 2D modelling of the edge plasma.

Integrated simulations of H-mode operation in ITER including core fuelling, divertor detachment and ELM control

“…In our present studies we extend the considerations in [1] by including the modelling of discrete ELMs [3] and of discrete pellets [12]. To determine the effect of discrete pellets, we have modelled the ablation and drift of pellet injected particles from LFS and HFS in ITER.…”

“…In addition, the relocation of the ablated pellet toward the LFS is so large that the residual core plasma fuelling of LFS pellets injected for ELM control is negligible (see figure 4). Therefore, the modelling with the continuous pellet model in [1] that considered the possibility of independent control of ELM triggering by LFS pellets and plasma fuelling by HFS injected pellets appears to be valid for modelling with discrete pellets. Note that particles expelled by ELMs practically do not penetrate back to the core due to opaque SOL [1].…”

“…Therefore, the modelling with the continuous pellet model in [1] that considered the possibility of independent control of ELM triggering by LFS pellets and plasma fuelling by HFS injected pellets appears to be valid for modelling with discrete pellets. Note that particles expelled by ELMs practically do not penetrate back to the core due to opaque SOL [1]. The energy loss in small controlled ELMs is assumed to be fully convective [1].…”

“…Integrated simulations of ITER H-mode plasmas including gas and pellet fuelling for core and edge density/divertor power load control and pellet pacing for ELM control have been carried out [1]. In these studies it was shown that the flexibility of the fuelling systems is appropriate to achieve high Q operation in ITER [1].…”

Heating neutral beams for ITER: negative ion sources to tune fusion plasmas

“…The ionisation cross sections correspond to those in [13]. The detailed description of the heat and particle transport models with consistent pedestal parameters and boundary conditions is described in [32].…”