Status of ITER project and research plan update | Yutaka Kamada

Thank you very much. So again, let me say spasibo – it is my big honor and pleasure to talk about the status of the ITER project and research plan update. I deeply appreciate you allowing me to join remotely. Thank you very much. This slide reminds us of the ITER mission: to demonstrate the scientific and technological feasibility of fusion power for peaceful purposes at reactor scale. The two representative targets are controlled fusion plasma with D-T fusion gain Q = 10, and demonstration of integrated fusion technology. ITER is a place for the world to cultivate fusion science, technology, and human resources. We have seven members, and I deeply appreciate the big effort of our Russian colleagues – not only the Russian domestic agency but also Russian plasma physicists and societies who sustain the ITER project. This slide shows key points of fusion plasma development by ITER. On the right, high integrated plasma performance should be demonstrated, with Q = 10, self-heating burning plasma requiring high density, temperature, energy confinement, and fuel purity, consistent with heat and particle flux control and divertor function. ITER also aims at Q = 5 steady-state operation with high power density and non-inductive current drive. Both must be achieved with disruption mitigation. On the left, the ITER tokamak is 30 m tall, 30 m in diameter, 23,000 tons, and requires an error field of order 10⁻⁴ of the total field, meaning millimeter-level manufacturing and assembly accuracy for a 10-meter-size device. Next, I am very happy to report that almost all manufacturing is going well. For the toroidal field coils made of Nb₃Sn conductors from six members, including Russia, 9 coils were manufactured in Japan and 10 in Europe. All 19 coils (18 plus one spare) have been completed, establishing the supply chain and mass production of large superconducting coils under ITER collaboration. For the poloidal field coils, PF1 was manufactured in Russia and delivered to the ITER site. The only remaining coil is PF3, to be completed this year – nearly all PF coils are done. For the central solenoid, four of six modules are manufactured, and two have been integrated at the ITER site. Moving to the divertor, the most challenging part: the divertor dome fabricated by Russia – a one-ton full-scale prototype passed acceptance tests with very good results, demonstrating thermal resistance under heat cycles up to 5 and 10 MW/m². The outer divertor target by Japan also successfully passed helium leak tests. Europe is manufacturing cassette bodies and inner vertical targets. These prototypes passed high heat flux tests of 6000 cycles up to 20 MW at an EU facility. We deeply appreciate the effort of the test institute. Other components like upper ports are progressing well. On assembly procedures: the cryostat base (1350 tons) was installed in May 2020, the cryostat lower cylinder in August 2020, then the lowest poloidal field coils PF6 and PF5 from China with gravity supports completed in 2021. The first sector module (40° vacuum vessel sector with two TF coils) was installed in May 2022. However, ITER faces big challenges with first-of-a-kind components. We found a non-conformity in the vacuum vessel: the weld beads needed rework due to lack of accuracy. We decided to bring the sector module out of the pit for repair. Also, we found a defect in the thermal shield due to chloride stress corrosion – about half of the seals need repair, half remanufacture. Repair work is ongoing; the first repaired sector module (number 7) will be completed this May/June, with reinstallation next year. The steady-state electric power supply system was completed in 2019; the reactive power supply will soon be complete, and commissioning has started. The water cooling system (3 × 1.2 GW heat rejection) is assembled and commissioned. The cryogenic plant for liquid helium is completed and commissioning started. For risk mitigation during initial integration, we are conducting cold tests of TF coils at nominal current (68 kA) and testing the Russian PF1 coil using a cryostat. Cold tests start in 2025. Now I discuss the new ITER baseline, to be proposed to the ITER Council in June. Two important points: staged safety demonstration and a technically feasible schedule. Because ITER explores new scientific territory with a large step from present devices, safety cannot be fully demonstrated at this stage but will be built along a planned roadmap based on operational findings. Due to repair needs and manufacturing delays, we adopted a technically feasible schedule rather than best technically achievable. The reference scenario: after assembly, we start the augmented first plasma (AFP) phase with almost all in-vessel components installed, including the divertor. AFP demonstrates an industrial-scale superconducting tokamak, nuclear fusion operation with H-mode, and commissions plasma control systems toward DT1. We plan 40 MW of ECH (originally 20) plus 10 MW ICRH for AFP. Then additional 27 MW ECH and 33 MW NB for DT1, aiming at Q = 10 short pulse (50 seconds) in the third campaign, and mission goal Q = 10 long pulse (300-500 seconds, 500 MW fusion power) in DT1. Key milestones: completion of superconducting coil manufacturing soon, tokamak assembly completion with high accuracy, H-field achievement, divertor plasma equilibrium, nuclear operation with DD and DT. We need development of plasma understanding, high performance with tungsten first wall, 100% disruption mitigation by SPI, RMP ELM control, and integrated modeling. A major decision: the first wall material is changed from beryllium to tungsten. Reasons: structural integrity concerns after disruption (melting of Be creates large electric circuits), need to achieve Q = 10 with tungsten, erosion of Be is too large for DEMO, and Be toxicity. But tungsten increases core radiation risk; however, impact assessments using world models show Q = 10 can be sustained. For risk mitigation, we prepare boronization systems, including a boron dropper. We collaborate with ITPA and see no showstoppers. Important R&D: characterization of alternative coatings like B₄C on tungsten, developed in Russia (up to 20 µm thick), under discussion between RFDA and IO. In AFP, we will commission control and protection with plasma up to 50 MJ, 5.3 T, develop scenarios up to 15 MA (L-mode) and 5 MA (H-mode with deuterium), and demonstrate disruption mitigation. In DT1 with full heating (67 MW ECH, 33 MW NB, 10-20 MW ICRH), we aim for Q = 10 at 500 MW fusion power, either with standard H-mode at 15 MA (Q95=3) or hybrid operation at higher Q95 (4) for easier disruption mitigation. Total neutron fluence in DT1 is 1% of full operation (equivalent to about 550 pulses of 300 seconds). Contributions expected from Russian devices include error field determination, plasma startup, disruption mitigation, runaway electron behavior, and testing of diagnostics and heating systems. Key issues for the tungsten first wall: fuel retention and removal, alternatives to glow discharge cleaning, tungsten impact on Q = 10, W source evaluation, screening, pedestal transport, and core transport – all requiring modeling and demonstration on existing tokamaks. The ITER Research Plan update team, led by Alberto Loarte and Mario Merola with five expert members including a Russian expert, supports the level-1 research strategy. The new plan will be presented to the Science and Technology Advisory Committee in May. Toward DEMO, plasma controllability is critical – we need to simplify control compared to ITER. Integrated modeling must be benchmarked against world tokamaks; I enjoyed the recent Globus-M results. ITER is one step to DEMO; we must demonstrate component manufacturing, assembly, system integration, commissioning, operation, and fusion standards. For example, assembly accuracy of 10⁻⁴ may be relaxed if physics can justify, reducing DEMO cost. Finally, let's construct and operate ITER together, achieve its milestones, and use ITER for your own fusion development: fostering next-generation scientists, industries, academia, and deciding on fusion regulation and standards. Thank you very much for your kind participation. Spasiba.