DISCUSION Y CONCLUSIONES

completion of details. The structures are now divided into two well-separated packages of approximately equal value: Coil-Casings (18 sets) and Outer Intercoil Structures plus Gravity Supports (18 sets). A precise sharing between Voluntary Contributors within the EU was agreed in the summer of 2009.

In the context of the JT-60SA Integrated Project Team, a formal review by external experts (panel chaired by R. Aymar) was also conducted in the summer of 2009. The panel concluded the review favourably and agreed that the design is mature to proceed with procurement initiation.

The technical specification for the High-T_c- Superconducting (HTS) current leads was completed and the interfaces were agreed with JAEA. The design of the current leads is largely based on the design for the current leads for the W7-X project. The final design review was successfully completed. High- Tc superconductor material was already ordered in advance because of its long delivery time. The technical level of the Procurement Arrangement and the Agreement of Collaboration was agreed between F4E and the Voluntary Contributors by the end of 2009. In the field of Power Supplies, the European contributions for the JT-60SA Power Supply (PS) system include the Base PSs for the Toroidal Field Magnet, the CS and EF coils, High Voltage generators for CS1-4 modules to provide the requested voltage for plasma breakdown, Quench Protection Circuits (QPC) for all superconducting coils, PS for In-vessel coils for Fast Plasma Position Control (FPPC), and PS to control RWM.

In the course of 2009, the technical and procurement preparation activities have proceeded in accordance with the Work Programme and according to the reference schedule. Relevant interface documents were developed, details of the sharing were concluded

and drafting and finalisation of the Technical Specifications documents has been progressing well leading to the conclusion of the Procurement Arrangement of the QPC as well as the finalisation of the Technical Specifications and PA material for the Base PS and High Voltage (HV) generators (the conclusion of which is planned for mid-2010). A complete model of the JT-60SA Poloidal Field coil circuit including all the passive structures was developed. The model was updated on the basis of the new geometric data of the Vacuum Vessel and stabilising plates, and it was utilised to analyse the effects of plasma initiation, disruption and of QPC intervention in terms of over-current.

Two different complete models of the JT-60SA Base PS system (including Motor Flywheel Generators (MFG)) were developed to verify MFG compatibility with the JT-60SA electrical loads and the thyristor converter performance. The obtained active and reactive power waveforms are utilised to design the AC power system.

View of JT60SA cryostat base and one TF Coil with structures

Development of the main characteristics of the JT- 60SA Base PS and TF PS was defined together with the basic assumptions for the operational procedure in case of fault. The basic fault sequence was established based on utilising the crowbar and the QPC.

The circuit configuration of the switching network unit (SNU) for the HV generation at plasma breakdown was studied to keep the plasma operational flexibility and to minimise the construction cost. As a result, the resistor of the SNU was divided into four different resistances for stable breakdown with different pre- magnetisation, and a further two resistors were added to assist fast plasma current ramp-up phase. The maximum energy consumption at each resistor was also defined. In addition. the basic layout of the PS System in the JT-60 Rectifier Building and Extra Area of JT-60 Experimental Building was defined. The place to install the FPPC coil power supplies on the ground floor of the Rectifier Building was defined. The necessary area for the RWM control coil and EFC coil power supplies will be evaluated in 2010.

For the Cryostat, compared with the Work Programme defined for 2009, some delays were accumulated in the finalisation and conclusion of the cryostat base PA: the main issue being the resolution of some internal EU administrative matters as well as the need to define more details in the technical design and specifications. Work in 2009 hence led to much more precise technical specifications than originally thought and this allowed the call for tender, by CIEMAT, to proceed with a reduced delay after the conclusion of the PA. The formal signature of the PA was carried out in late 2009. Additionally intense design work on the cryostat main body has also been carried out in 2009 aiming to reduce costs, simplify assembly as well as reduce the complexity of the sharing between EU and JA. This latter issue was solved in late 2009 with a revised sharing of work which is deemed to be easier to implement by substantially reducing interface issues between potential industrial suppliers.

For the cryogenic system, technical and procurement preparation activities have proceeded in 2009 as originally planned within CEA and F4E. Design work in 2009 has focused on two main lines: design optimisation based on detailed analysis and industrial feedback, as well as simplification of interfaces between EU and JA. Based on such studies in 2009, the main interface with the cryogenic system became at the outlet of the Auxiliary Cold Box (ACB) in the RF Amplifier Room III. In 2009 two studies were performed by European industry to analyse in detail the refrigeration process. As part of these studies, the major components were dimensioned and a new layout of the cryogenic system was proposed. The

warm compressor station will be placed in a new building next to the cryogenic hall. Warm gas storage vessels will be placed outside the main buildings. The refrigerator coldbox and the ACB are placed in a separate cryogenic hall which also holds the liquid helium storage. During plasma pulses the refrigeration powers show significant peaks which have to be handled by the refrigeration system. Studies have been conducted and measures were proposed by industry to keep the magnet temperatures within the required temperature range. All major interfaces with the Naka site were defined and estimates for the utilities, investment and operation resources have been provided.