The latest harvest of ITER construction photos may be taken from the same point—the tallest crane on site—but there is always an abundance of new detail to be gleaned. A year ago, the Assembly Building had just been insulated with several layers of cladding and equipped with overhead handling cranes; work on the circular bioshield was newly underway; the cryoplant was still at foundation level; and a large stretch of land now occupied by the twin Magnet Power Conversion buildings was but a barren steppe.   A large covered parking area has been added to the contractor zone at right, where other temporary buildings house contractor teams, workshops and user facilities such as the canteen and infirmary. Currently, there are 1,900 workers participating in ITER construction in two daily shifts. Today, in the seventh year of ITER building construction, the platform seems to have no room to spare. Activity has mushroomed in all corners and the pace of progress difficult to keep up with.   When we resume publication in September, things will have changed again. And as Newsline has done for more than ten years now, it will continue to cover and document what is happening not only on the ITER site and within the ITER Organization, but also within the global ITER Project and the worldwide fusion community.   In the meantime, we hope you will enjoy this selection of summer postcards.   Some 3,300 cubic metres of concrete have already gone into the ITER bioshield (circular structure, at right); pouring is underway now on the L3 level and the first rebar has been set in place for L4. The other structures of the Tokamak Complex—the Tritium, Tokamak and Diagnostics buildings—are advancing each at its own rhythm. By the time assembly activities get underway late next year, the Complex will have a roof ...

ITER's steel-and-concrete bioshield has become the defining feature of Tokamak Complex construction. Two levels only remain to be poured (out of six).   It is a "ring fortress," with walls up to three-metres thick, that will completely surround the Tokamak and protect workers and the environment from the radiation generated by the fusion reaction.   Over the past year, we've seen the walls rise steadily. Six months ago, part of the first above ground level (L1) could be seen and work was starting on L2. Today L2 forms a complete ring, the first pours are underway for L3, and some rebar elements have already been installed for top level L4.    Now, let's get inside the fortress and see what's happening there ...

A year ago, work was just beginning on the steel reinforcement for the building's foundation slab. The Radio Frequency Heating Building is now nearing the last stages of completion. The space inside the 26-metre-tall building will be shared by two radio-wave-generating systems designed to feed energy, in the form of electromagnetic radiation, into the plasma. Power supplies for both resonance heating systems (a total input of 100 MW) will occupy the better part of the first two floors, while the top floor will be reserved for the wave generators—gyrotrons for electron cyclotron resonance heating (ECRH) and ion for the ion cyclotron resonance heating (ICRH). The construction of the Radio Frequency Building is nearing completion, with small regions of the second and third floor to be poured and removable internal hatches to be installed. The final task for the structural part of the building will consist in inserting two overhead cranes.

Since the giant poster was added to the Assembly Hall's completed exterior in June 2016 the building has looked from afar like a finished project. But inside, teams have been advancing on finishing works—installing plasterboard, lighting, fire protection, cable trays; jointing and painting; and creating stairwells and a lift. Most recently, a first coat of varnish was applied to the floor to limit dust, testing of the overhead cranes started, and a special zone was prepared for the building's first and most impressive assembly tools, the twin vacuum vessel sector sub-assembly tools. European contractors successfully achieved an ITER Council milestone in late June by making one part of the Assembly Hall "ready for equipment."     These anchor bolts are ready to receive the wing rails and columns of the vacuum vessel sector sub-assembly tools. On this reinforced area of the Assembly Building basemat, contractors will begin tool installation activities in August. By the end of the year, the first tool should be standing 22 metres tall. In this image, the Tokamak Building has been finalized and the temporary wall that closes it off from the Assembly Building has come down. We see the full crane bay, with the machine assembly area in the background. Also evident, the semicircular "footprint" of the sector sub-assembly tools, which is already traced out on the reinforced basemat of the Assemly Hall (see second photo). This 10-metre-tall "box-in-a-box" has been erected in the Cleaning Facility (at the entrance to the Assembly Hall) to store the elements of the sector sub-assembly tools. Crates of tool components have been arriving since June from Korea (the first are pictured here).

They look like perfectly aligned emergency housing units. But of course they're not: the 18 concrete structures in the ITER cryoplant are massive pads that will each support one 25-tonne helium compressor skid. What appears as "windows" in the concrete blocks are but passages for the dense interconnecting piping. The concrete blocks are decoupled from the floor in order to prevent vibrations from being transmitted to other systems.   Eighteen helium compressor units will be grouped in the liquid helium plant and operated in parallel to provide the necessary gas flow for the liquid helium cooling needs of the Tokamak. The Compressor Building of the cryoplant will also house other helium compressors as well as compressors for the liquid nitrogen plant.   The helium compression system of the liquid helium plant involves the use of oil-flooded screw compressors and a large amount of oil. The fact that the compressors are installed at a height of approximately four metres allows the oil to regain the oil separation system through gravity.   In the 3,400 m² available in the Compressor Building, contractors will install 18 oil-flooded screw compressors for the helium plant as well as other helium compressors and compressors for the liquid nitrogen plant. Oil acts as a lubricant in the compressor system, and also takes away some of the heat from the cycle. Following compression, the helium (all oil removed) flows to the liquid helium cold boxes in the adjacent building.   In general, the heat generated by the compressors of the liquid helium plant will be evacuated by the flow of a large volume of cooling water—equivalent to 2,500 m3/hour. A part of the thermal energy will be recovered (approximately 12 MW) and used in the heating of other ITER buildings.   The Compressor Building occupies more than half of the space (3,400 m²) available in the cryoplant.

They are the most recent additions to the ITER construction landscape. Long and low, the twin Magnet Power Conversion buildings are going up parallel to the ITER cryoplant. According to the ITER schedule, they will be ready for equipment before the end of the year. The relatively straightforward structures—each 150 metres in length—are going up rapidly on the ITER site. At the same time, contractors are finalizing buried technical galleries between the buildings. By the end of the year, contractors will begin installing the equipment. Densely packed with electrical converters, switches and fast discharge units, the twin Magnet Power Conversion buildings act as an AC/DC converter for the ITER magnetic system. The procurement responsibility for the electrical equipment in the buildings is shared by Korea (18 converter units and one master control system), China (14 converter units), and Russia (fast discharge units and some 2.5 kilometres of busbars).

If ITER were an industrial fusion plant, the better part of the heat generated by the burning plasmas would be used to produce pressurized steam and (by way of turbines and generators) electricity. Only residual heat would need to be dissipated. But as an experimental installation, not designed to produce electricity, ITER will need to evacuate and dissipate all the power the fusion reaction generates.   And this means a lot. During the plasma burn phase, the amount of heat to be evacuated from the Tokamak and its auxiliary systems will be in the range of 1100 MW.   The complex system of piping, pumps, open and closed loops that form the ITER cooling water system ends up here, in a 6,000 m² area that accommodates cold and hot basins with a total volume of 20,000 m³ as well as an induced-draft cooling tower installation located above the cold basin.   Seen from above, the cooling water zone at the northeast end of the ITER site. These supersize pipes (one metre and more in diameter) for the heat rejection system are designed for a flow rate of two cubic metres per second.