When running an international enterprise like ITER, with colleagues all over the world, it is indispensable to have regular, personal interaction. ITER Director-General Osamu Motojima set off to Korea during the first week of October on this very mission: visit some of the manufacturing facilities where ITER components are taking shape and meet Myeun Kwon, former Director of the KSTAR Research Centre and newly appointed president of the Korean National Fusion Research Institute (NFRI), and Gyung-Su Lee, Chairman of the ITER Management Advisory Committee (MAC).
The first stop was SFA Engineering, an automation equipment company with vast experience in nuclear fusion. In March 2010, SFA signed a contract
with the Korean Domestic Agency for the design of 18 custom assembly tools.
The following day, a visit to Hyundai Heavy Industries (HHI) and its sub-supplier Ilsung was on the agenda. Both companies are located in Ulsan, South Korea's seventh-largest metropolis. HHI, the largest ship-building company in the world, will manufacture sectors 1 and 6 of the nine-sector ITER vacuum vessel. As subcontractor to HHI (contract signed in August 2010) Ilsung will be responsible for manufacturing the equatorial and lower ports for these sectors.
In order to verify the design and manufacturing feasibility of the vacuum vessel sectors, HHI has fabricated three types of full scale mock-ups: The inboard segment mockup (VISM) for electron beam welding process optimization and the inner wall shielding assembly trial; the vacuum vessel upper segment mockup (VUSM) for process optimization, assembly feasibility and a welding distortion study between outer shell and flexible support housings; and the vacuum vessel lower segment triangular support mockup (VLTM) for a study of fabrication feasibility.
In addition to assembly tooling and the manufacture of two vacuum vessel sectors, Korea also has procurement responsibility for the AC/DC converters for the ITER switchyard. Director-General Motojima made a final stop to Dawonsys, under contract with the Korean Domestic Agency to perform prototype R&D and testing. Dawonsys provided the power systems for the superconducting magnets as well as the high-voltage power system for the KSTAR tokamak
All assemblies—from the output of DC busbars
, to the input of AC busbars, to a full-scale, six-pulse central solenoid converter unit—were engineered and integrated in the prototypes. Essential parameters such as temperature rise at rated current, good current sharing among paralleled thyristors, fuse coordination, and the soundness of the converter structure over the electromagnetic stress at fault condition were confirmed by the prototype converter.
The contract for AC/DC converters signed on 12 August between the Korean Domestic Agency and Dawonsys is expected to run for seven years, and covers the design, fabrication, site assembly and installation, and technical assistance during the integrated circuit test. The converters for ITER's toroidal field and central solenoid coils, vertical stability coils and correction coils (including master controllers, a dummy load, and spares) are deliverables on the contract.
"This was a very nice occasion to confirm the progress of real manufacturing and the large potential of the involved Korean institutions", DG Motojima summarized his impressions.
We'd like to thank Junho Ko from ITER Korea for his contribution to this article.