The Development of First Plasma Operations on ITER

ITER construction is well underway and first plasma operations are planned at the end of 2025. Plant system commissioning has begun and will proceed up to the closure of the cryostat in late 2024, which defines the start of integrated commissioning, including that of the Central Interlock System (CIS), the Plasma Control System (PCS), and associated diagnostics to ensure investment protection and central control functions can be carried out. An independent system will also be commissioned for superconducting magnet protection to avoid approaching force, field, and temperature limits. First plasma scenarios in hydrogen with B_T = 2.65 T will first attempt Ohmic breakdown within a neutral pressure range of 0.3 mPa < p < 0.7 mPa, limited by runaways at the low end and by inability to ensure I_p ≥ 100 kA for ≥ 100 ms at the high end. If Ohmic breakdown is unsuccessful, electron cyclotron heating will be added in 0.83 MW steps for short pulses (< 300 ms), possibly up to 6.7 MW injected at 2^nd harmonic. The PCS must ensure that I_p < 1 MA to stay within structural limits of the vacuum vessel supports to the temporary poloidal stainless steel limiters. A backup option to improve breakdown is to operate at full toroidal field of 5.3 T with 1^st harmonic ECH after magnet commissioning.