The superconductors for the ITER magnet system are among the longest-lead production items for the project; the first five Procurement Arrangements concluded by the ITER Organization between late 2007 and mid-2008 concerned the conductors for the toroidal field magnet system.
The Russian Domestic Agency is responsible for 20 percent of toroidal field conductor procurement and 14 percent of poloidal field conductor procurement. Production is ongoing according to the schedule of the Procurement Arrangements.
On 25 June, the second batch of toroidal field conductor unit lengths started on their way from the premises of the Kurchatov Institute in Moscow to the city of La Spezia, Italy, where the winding of ten toroidal field coils will take place.
Demonstrating the attachment of Russian industry to fulfill its contractual obligations on time, two 415-metre production lengths of niobium-tin (Nb3Sn) conductor for toroidal field side double-pancakes were loaded onto trucks at the Institute. This latest shipment follows the delivery of four conductor unit lengths to Europe in October 2012, including a copper dummy and a 100-metre qualification length.
Seven similar units lengths have passed all of the tests stipulated in the Procurement Arrangement and meet ITER Organization requirements; they will, in turn, be shipped as well.
During this week’s meeting of the ITER Council in Washington, four Procurement Arrangements were signed between the ITER Organization and Domestic Agencies, taking the total in-kind procurement value of ITER construction to the 80 percent mark.
Number one was the Procurement Arrangement for ITER’s Pulsed Power Electrical Network (PPEN), which will supply alternating current (AC) power to the machine’s superconducting coils and its heating and current drives. This mighty power source will be procured by China. The PPEN will absorb 500 MW and 200 Mvar pulsed power for the pre-programed physics scenarios and plasma current, position and shape control. The power will be distributed from three main 66kV busbars and three main 22 kV busbars that will normally operate uncoupled from one another.
The loads connected to PPEN are mainly large thyristors based AC/DC converters rated typically in the range from 5 to 90 MVA.
Most of the large and dynamic loads are directly fed from the 66 kV busbars, that is to say the AC/DC converters feeding the superconducting magnet coils and the neutral beam system providing plasma current. The loads with relatively lower power (normally less than 20 MVA/unit) are fed from the 22 kV busbars.
The Procurement Arrangement signed with the Chinese Domestic Agency comprises the manufacture, inspection, testing, packaging, shipping and provision of on-site technical assistance during the onsite assembly, the subsequent acceptance tests and the commissioning and integration of the items; this applies to all the items, structures, materials and mechanical and electrical facilities for the new 400 kV substation and the transformers associated with the 400/66/22 kV supplies and the 66/22 kV items and cable.
The second Procurement Arrangement signed in Washington concerned the low field side reflectometer. This diagnostic system will monitor electron density and aid in the assessment of fusion performance. Understanding and monitoring electron density profile evolution and density fluctuations is essential for assessing the stability of fusion performance inside a tokamak.
Along with Victor Udintsev from the ITER Organization, Greg Hanson of Oak Ridge National Laboratory’s Fusion Energy Division and Tony Peebles of the University of California at Los Angeles have been working on the conceptual design of the reflectometer with an international team that includes staff from ITER; the University of California, Los Angeles; Oak Ridge; and the Princeton Plasma Physics Laboratory.
ITER’s complex diagnostics are configured at ports in the vacuum chamber around the plasma vessel, monitoring and providing data over time of the evolution of plasma properties such as electron density and temperature. Besides providing data on the electron density profile evolution, the new reflectometer will monitor small-scale density turbulence and larger-scale magneto hydrodynamic modes inside the plasma, such as fast-ion driven instabilities. Such instabilities can cause the plasma to lose heat, particles, and momentum. It is important for the safety of the ITER device to understand and monitor the amplitude and spatial distribution of these instabilities, so that researchers can project forward to the next-stage fusion reactor.
Wednesday, 20 June also witnessed the signature of the first of four Procurement Arrangements that are to be signed for the procurement of ITER’s powerful 1MW microwave sources (gyrotrons). This week’s Procurement Arrangement was signed with the Russian Domestic Agency, which will be providing 8 of the 26 gyrotrons installed on ITER. Each gyrotron generates roughly the equivalent of 1,000 microwave ovens in a relatively compact single tube roughly 2 m in height and ≤50 cm in width. The Russian scientific teams have extensive experience in developing gyrotrons of various powers and frequencies for research facilities around the world.
Part of ITER’s electron cyclotron team had the chance last year to visit the Russian laboratories and witness the highly reliable operation of the gyrotron for near 1MW output power and pulse lengths of >600sec. The Russian teams in Nihzny and Moscow have produced several ITER-like prototype tubes that have demonstrated performance equivalent to ITER operation needed for the Q≥10 / 15MA scenario. The first gyrotron is planned to be delivered to the ITER site in France in early 2016 and will be used to generate the spark to start the very first plasma in ITER.
Last but not least, an amendment to the Procurement Arrangement on the Vacuum Ultra-Violet (VUV) Edge Imaging Spectrometer was signed. The primary role of the Core Survey VUV system is to monitor all impurities in the main plasma.
The primary role of the Divertor VUV spectrometer is to monitor impurities in the Divertor, especially Tungsten lines around 25 nm. These PA amendments complete the scope of the Korean Domestic Agency for VUV spectroscopy.
We would like to thank Lynne Degitz (US Domestic Agency), and the ITER responsible officers for these Procurement Arrangements Jose Gascon, Caroline Darbos, Mark Henderson and Robin Barnsley, for their contribution to this article.
An important step forward for the development of the 24MW electron cyclotron was achieved this past Thursday. During the 13th Management Advisory Committee meeting this week, the ITER Organization concluded its 75th Procurement Arrangement for the Electron Cyclotron High Voltage Power Supplies with the European Domestic Agency.
The high voltage power supply forms the backbone of the electron cyclotron plant, providing up to 90 kV and 50A to each of the twenty-four 1MW microwave sources. The power supplies provide a high regulation of the applied voltages to actively control delivered power to the plasma based on the plasma requirements. The high regulation is based on the Pulse Step Modulation technique, which essentially stacks several smaller power supplies (or modules) in series. A rapid controller turns each module on and off to provide an accuracy of ±1 percent and modulation frequencies of up to 5kHz.
The European Domestic Agency Fusion for Energy will provide 8 of the 13 power supplies to be delivered to ITER; the remaining 5 power supplies will be procured by the Indian Domestic Agency. If all goes well, the Procurement Arrangement with India will be signed this summer. The first high voltage power supply is scheduled to arrive at the ITER site in late 2015.
The ITER Organization has signed a total of 10 Procurement Arrangements in 2012: eight full Procurement Arrangements and two amendments.
One of the greatest challenges to monitoring the production of the large and complex components at the heart of the ITER magnet system is the quick and efficient exchange of quality assurance/quality control (QA/QC) documents and data—important information that needs to be reviewed during the manufacturing process and cleared for acceptance by the responsible Domestic Agency and the ITER Organization.
Following the successful implementation of the Conductor Database tool that tracked production data for the ITER conductors at six Domestic Agencies and their suppliers right through to final acceptance tests, it was decided to develop and implement a Magnet Manufacturing Database (MMD) on the same model.
The Magnet Manufacturing Database will be the main tool for monitoring the QA/QC processes of the Procurement Arrangements for magnet coils, magnet structures and magnet feeders. This web-based application, integrated into ITER’s collaborative platform ICP, provides data and process integration with unified access and workflow. For the manufacturers, it offers an inventory control system with the possibility of integrating test result data and acceptance criteria functionalities, and of automatically generating barcodes and lot/serial numbers to facilitate tracking.
For the ITER Organization, the workflow management system included in the database matches the control points defined in each Procurement Arrangement and the manufacturing processes defined in the Manufacturing Inspection Plan. References to ITER documents are included for procedures, instructions, and specifications … allowing the ITER Organization to identify and manage critical operations such as welding.
The Magnet Manufacturing Database can manage any kind of complex manufacturing process chain, regardless of product type. Real-time production status and work-in progress monitoring will be also developed in a near future, using the IT online reporting system to extract and display data from the database in an efficient manner.
The success of such a tool will rely on the ability of its users around the world to input data in a timely manner. After a prototype implementation at the European Domestic Agency for the toroidal field coil winding packs, representatives of the ITER Magnet Division were in China mid-May to provide extensive training to the staff of the Chinese Domestic Agency, its supplier ASIPP, and some of the ASIPP sub-suppliers to launch the Magnet Manufacturing Database for the feeders, high temperature superconductor leads, and correction coils.