Status of the JT-60SA project: An overview on fabrication, assembly and future exploitation

JT-60SA is a superconducting tokamak developed under the Satellite Tokamak Programme of the BroaderApproach Agreement between EU and Japan, and the Japanese national programme. It is designed tooperate in the break-even conditions for long pulse duration (typically 100 s), with a maximum plasmacurrent of 5.5 MA. Its scientific aim is to contribute at early realization of fusion energy, in support tothe ITER project and also to future DEMO devices by addressing key engineering and physical issues foradvanced plasma operation.The JT-60SA Project has shown steady progress in the last years: from the design of the main compo-nents, started in 2007 in a close collaboration between EU and Japan, continuing through the assembly inthe torus hall, started in January 2013 with the delivery of the first large European component, the Cryo-stat Base. Since then big milestones have been achieved, like the complete winding and pre-installationof the three lower Equilibrium Field (EF) coils, the welding of a 340◦of the Vacuum Vessel sectors, andthe completion of most of the Toroidal Field (TF) Coils.Outside the tokamak hall, large auxiliary plant like the Cryogenic System (CS) and the Quench ProtectionCircuits (QPC) have been fully installed and commissioned, while the Switching Network Units (SNU) andTF and EF coils Power Supplies (SCMPS) are completing installation on site. Other components such asCryostat Vessel, Thermal Shields, In Vessel Components and so forth are being manufactured and beingdelivered to Naka site for installation and commissioning.This paper gives technical progress on fabrication, installation and assembly of tokamak componentsand ancillary systems, as well as progress of JT-60SA Research Plan being developed jointly by EU andJapanese fusion communities

Progress of the magnetic sensor development for JT-60SA

In order to obtain information for control of JT-60SA plasma and physics research on the plasma, many types of magnetic sensors are developed. We have designed a new architecture of magnetic sensors and connection methods for JT-60SA taking installation and maintenance into account. The former include a newly designed Mirnov coil, a Rogowski coil and a diamagnetic loop. They enable us to make simple and robust sensors. The latter include a newly developed connector between a sensor and a mineral insulation cable, and a connection box. An unsealed connection box enables easy installation in a vacuum vessel; however, it should have a withstand voltage greater than 1 kV at intermediate gas pressures. We successfully achieved a high withstand voltage for the unsealed connection box in the gas pressure region around the Paschen minimum voltage. After R&D of JT-60SA magnetic sensors, almost all manufacturing steps are complete. This paper reports the manufacturing and tests of the magnetic sensors for JT-60SA