Description
Deuterium plasmas are going to be used at Start of Research Operation (SRO) for early H-mode demonstration and in the first Deuterium-Tritium (DT-1) phase of the ITER Research Plan (IRP). The main goal of deuterium operation in these phases is to allow the development of H-mode scenarios with high plasma performance and low neutron production. This is possible thanks to the increased additional heating power level in the new baseline, which allows D H-mode operation to high plasma current, (40 MW ECH + 10 MW ICH for SRO and 60 MW ECH + 10 MW ICH + 33 MW NBI for DT-1) compared to the 2016 baseline (20 MW ECH for PFPO-1 and 20 MW ECH + 20 MW ICH + 33 MW NBI).Here we study the optimisation of operation with minimal neutron production for a range of plasma currents, densities, and mix of Radio Frequency and Neutron Beam Injection (NBI) heating and current-drive. The emission of 2.45 MeV neutrons from DD reactions as well as 14 MeV neutrons from DT reactions, including slowing down of 1 MeV T ions born in DD reactions, is assessed for key plasma currents in the IRP and different plasma densities for full- and half-field operation. The simulations are carried out by self-consistent 1.5D transport simulations of the core plasma parameters by ASTRA code with the pedestal and boundary conditions predicted by EPED1 and SOLPS codes, and with self-consistent gas puffing and pellet fueling, taking account of limitations on the NBI shine-trough losses. The results of this assessment are needed to provide the background for the choice of plasma scenarios for the ITER Research Plan in SRO and DT-1, within the limits of the neutron budget imposed for such operational phases, and for associated assessments.