Central Solenoid (CS) components have an abundance of technical challenges ranging from material science to component interfacing. In manufacturing, a CS module is subjected to stringent high voltage insulation strength tests at multiple occasions. The engineering challenge is where a multitude of quench detection wires need to exit the bulk insulation and the materials boundary or compatibility become an issue. In assembly, each CS module terminals is jumped to its respective feeder line via an extension lead that is manufactured with interfacing constraints with the module terminal vector as well as the feeder terminal mating surface. Another critical aspect is the clearance available in assembly with other surrounding tokamak components. A summary of the issues found in manufacturing of large scale structural components is also given.

This paper describes critical assembly process qualifications, acceptance criteria, and worker training of ITER Central Solenoid Assembly. Coaxial joint assembly was qualified and trained to achieve resistance below 4.1 nOhm. The electrical insulation process was qualified to 30 kV and 15 kV under Paschen conditions. Shear pin drilling and installation within specified tolerance was achieved. Modules were lifted and positioned within 2 mm. The lessons learned, and subsequent work execution onsite within the IO facility assembly hall are also presented.

The Central Solenoid (CS) is a key element of the ITER Magnet system, including six identical coils, called modules, assembled together to form a 4 m outer diameter, 13 m high solenoid. It is a superconducting magnet, with a peak field up to 13 T. The magnet is enclosed inside a steel structure providing vertical pre-compression and mechanical support. The room temperature pre-compression load is necessary to prevent displacement and gap between coils during the exploitation phase and therefore reduce the CS performance and create mechanical stress. The target CS pre-compression is 210 MN realized by the tightening of 45 Multi Jack Tensioners (MJTs) divided in 9 sectors. Procurement of the components and the procedures of the ITER CS is the responsibility of the USA Domestic Agency (USDA), while the ITER Organization (IO) will carry out the assembly of these components. IO signed in 2018 a collaboration agreement with CEA/IRFM to implement the pre-compression procedure proposed by the USDA using a dedicated mock-up with the main objectives: - Simulating the all modules stack rigidity with Spring plates; - Characterize the young's modulus of one CS section module; - Validating the technical procedures proposed - Estimating the time impact to accomplish the CS pre-compression process in accordance to the complete ITER Tokamak assembly. The CS mock-up Pre-compression Verification (CSPV) uses a 1/9 segment of the overall CS with a mix of ITER Tokamak and mock-up components. The target load of the mock-up is 23.3 MN to be in accordance with the overall CS pre-compression load value. This paper presents the CSPV mock-up activities, the challenges encountered and the results gained. As a conclusion, the tightening process is highlighted to estimate its applicability for the ITER CS assembly in term of technical and organisational aspects. The views and opinions expressed herein do not necessarily reflect those of the ITER Organization.

The Central Solenoid (CS) is a key element of the ITER Magnet system, including six identical coils, called modules, assembled together to form a 4 m outer diameter, 13 m high solenoid. It is a superconducting magnet, using a 45 kA Nb3Sn conductor internally cooled by circulation of supercritical helium at 4.5 K with a peak field up to 13 T. It is enclosed inside a structure providing vertical pre-compression and mechanical support. Procurement of the components and the special assembly tooling of the ITER CS is the responsibility of US ITER, the ITER Domestic Agency of the USA, while the ITER Organization (IO) will carry out the assembly of these components. US ITER has awarded several contracts since 2011 to supply seven modules, including a spare, structure components, and the special tooling required for the CS pre-assembly. All deliveries are organized with the objective to start the CS assembly at IO site by the end 2021. IO has organized special process training and is now starting first phases of the assembly mostly focused on on-site assembly contractor. The paper describes the CS module manufacturing and delivery status, reports the special process final development and training, and assembly status. In particular, the outcomes from first modules factory acceptance tests results will be reported as well as the development and training for special activities to start the first module stacking. The bus bar joint and pre-compression processes with their related tooling qualifications will be detailed.

The Central Solenoid (CS), a key component of the ITER Magnet system, using a 45 kA Nb3Sn conductor, includes six identical coils, called modules, to form a solenoid, enclosed inside a structure providing vertical precompression and mechanical support. Procurement of the components of the ITER CS is the responsibility of US ITER, the US Domestic Agency (USDA), while the assembly of these components will be carried out by the ITER Organization (IO). Procurement of all the coil modules was awarded in 2011 to General Atomics, while procurement of the structure is split among several manufacturers, using existing equipment, sometimes among the largest ones in the world. Assembly of the ITER CS will require a dedicated area in the ITER Assembly Hall, conventional tooling and special tooling. US ITER is in charge of the procurement of special tooling, while IO is responsible for the procurement of the conventional ones. A detailed assembly procedure is under development at US ITER, in close collaboration with IO and with the support of CEA. Procurement of the special Assembly Tooling is carried out by US ITER and the main part of the first item, the Assembly Platform, was delivered to IO in 2017.