On 21 June, one week after the ITER Council, Director-General Osamu Motojima paid a visit to Naka in order to see for himself the extent of the damage and discuss the recovery plan with Dr. Hiromasa Ninomiya, director general for fusion at Japan's Atomic Energy Agency. Mitigating the consequences of the Japanese situation on the ITER schedule was a key issue in the discussion.
On 21 June, an important meeting relative to ITER's nuclear licensing took place in Fontenay-aux-Roses, outside of Paris. Representatives of the ITER Department for Safety, Quality and Security met with members of the Groupe Permanent—the safety advisory body to the French nuclear regulator ASN that is charged with the technical examination of the ITER nuclear licensing files. This was the mid-course meeting of the examination process.
During a presentation on the status of the examination process, the technical advisors to the ASN (IRSN - Institut de Radioprotection et de Sûreté Nucléaire) affirmed that the quality of the answers submitted by the ITER Organization and the strict respect of deadlines opened the way for the establishment of the date for the final Groupe Permanent at the end of November 2011. This was approved by the French nuclear authorities and the president of the Groupe Permanent.
The examination process began back in July 2010. Since then, a thousand questions have been raised by IRSN on the Preliminary Safety Report (RPrS) and there have been three or four meetings per month. In parallel to activities on a national level, the Local Commission for Information is preparing its final commentary on the creation of the ITER Basic Nuclear Installation (INB) under French law. The Special Working Group created to analyse the ITER data also asked more than 300 questions to members in order to prepare its opinion which will be issued shortly.
On 15 June a five-week Public Inquiry began. During the Public Enquiry, the public has the opportunity to make comments on and ask questions about the ITER project, in particular its environmental impact and safety aspects.
The question of how to improve control of Edge Localized Modes (ELMs) and the vertical stability (VS) of the ITER plasma was one of the key issues addressed in a recent meeting of the ITER Science and Technology Advisory Committee (STAC). Since the Preliminary Design Review performed in October 2011, the in-vessel coil design team lead by the Princeton Plasma Physics Laboratory (PPPL) worked with two suppliers from Canada and China to fabricate the largest Stainless Sheath Mineral Insulated Conductor (SSMICC) ever produced in the world.
"Because of their proximity to the plasma, conductors with conventional insulation schemes were not an option for the in-vessel coils," says Edward Daly, the mechanical engineer who led the design efforts. The team therefore decided to choose SSMIC for its ability to withstand ITER's high radiation and bake-out temperatures of 200°C.
The sheer scale required for the ELM and VS coils in ITER, however, is much larger than anything produced previously. In June, contracts were awarded to the Institute of Plasma Physics at the Chinese Academy of Science (ASIPP) based in Hefei, China and to Tyco Thermal Controls, Ltd in Ontario, Canada, who both developed prototypes within four months. Once received at PPPL, the prototypes were cut, pushed, pulled, bent, heated, electrified, sliced and x-rayed to evaluate their mechanical and electrical properties. "In general, the conductor samples performed as we had hoped and expected," says Ed Daly. "There were no show-stoppers, but there is still work to do." The results will be used in the final design and prototyping phase, planned to start in July. ASIPP has expressed interest in manufacturing these coils and has proposed collaboration with PPPL.
The first Procurement Arrangement for ITER’s Diagnostic Division was signed by ITER Director-General Osamu Motojima and the Head of the Korean Domestic Agency, Kijung Jung. The Procurement Arrangement covers the Neutron Activation System, a technology to measure actual fusion power, and the Vacuum Ultra Violet (VUV) Edge Imaging Spectrometer, which measures the impurities in the ITER plasma. The signature—a symbolic step forward to the challenging journey of ITER diagnostics—took place in a quiet side event during the recent ITER Council meeting in Aomori, Japan.
There will be six different technologies installed in and around the ITER machine to measure the neutron emission and ultimately the absolute fusion power generated. One of them is the Neutron Activation System that relies on a pneumatic transfer system through which small capsules containing different metals such as aluminum, iron, niobium or tungsten are brought close to the plasma. The system works very much like the pneumatic tube delivery systems found in pharmacies or big libraries. Stored in a transfer station in the Tokamak Building, the capsules are sent off to the vacuum vessel via a system of bended, double pipes made out of ITER-grade stainless steel, a material which can withstand temperatures up to 800°C. The tubes are connected to the vessel by feed-throughs between the shielding blankets. Once the capsules have arrived, a pneumatic flap closes the tube and stops the target for 10 seconds. During this time the neutrons escaping the plasma do their work (i.e., they hit the target which becomes radioactive). The flap is then opened again and the target catapulted back to a counting station where the neutron induced γ-ray activity is measured. The fusion power is estimated by taking into account the nuclear properties of the target materials and the measured gamma activity.
Neutron Activation Systems (NAS) have delivered reliable results on various existing tokamaks such as TFTR and JET. "The system installed at JET was our reference design," explains Luciano Bertalot from the ITER Diagnostics Division, "which, together with our Korean colleagues, we developed further to adapt to the hotter and harsher conditions on ITER." The improved design is currently being tested on the Korean tokamak KSTAR. And it will be Korea that will ultimately build the NAS system for ITER. "The Korean Domestic Agency, with full responsibility and in close collaboration with the ITER Organization, will do its best to implement the NAS system and to have it built for the fusion power measurement on ITER," said H.G. Lee, on behalf of ITER Korea.
Further information available at http://www.iter.org