Here it is: the completed ground support structure
The first-phase works in the Tokamak Pit are over. The next stage: the civil works on the Tokamak Complex, beginning with the creation of a reinforced basemat on top of the seismic pads. Photo: Engage-AP
Between the rough face of the rock and the 15-metre-tall retaining walls, a space persists. At a later stage in the contruction works the space will be filled with sand and gravel and compacted. Photo: Engage-AP
Support in the shape of a star for the ITER experimental device: the very device that aims to bring the energy of the stars down to Earth. Photo: Engage-AP
The ground support structure for the Tokamak Complex—basemat and walls—is now complete. The retaining walls maintain and stabilize the surrounding rock and "waterproof" the Seismic Pit. Photo: ITER Organization
Construction on the retaining walls of the Tokamak Complex Seismic Pit ends in April. A branch is hung from one of the tallest points to symbolize the end of works—a construction tradition originating in Eastern Europe called "topping out." Photo: ITER Organization
From the side, it's easy to see that the retaining walls measure 1.5 metres at their base, 1.0 metres in the middle, and 0.5 metres at the top. Photo: ITER Organization
The concrete pillars (1.7 metres tall) and their seismic pads form an army of standing columns upon which the Tokamak Complex will be built. The area between the two concrete basemats will remain accessible for regular inspection of the seismic pads. Photo: ITER Organization
Formwork used to shape the retaining walls is supported during drying time. The space between the walls and the rock face will be filled with a mix of gravel and sand and compacted. Photo: ITER Organization
Section by section, the top, 0.5-metre-thick segment of retaining wall is set into place. Work on the walls will finish in March. Photo: ITER Organization
The excavation of the Tokamak Complex Seismic Pit, which required the displacement of 210,000 cubic metres of earth and rock, was completed in February 2011. One year later, progress made on construction is spectacular. Photo: F4E
As of early February 2012, 481 out of 493 concrete plinths had been cast (the formwork used for these 90 x 90 cm pillars can be seen in white and black in the photo). Three hundred and four plinths have now been topped with seismic bearings. Photo: ITER Organization
Among the "standing soldiers" at the bottom of the Tokamak Pit, it's easy to distinguish the future location of the machine by the spokes that branch out from a central plinth. Photo: ITER Organization
The 1.5-metre-thick Seismic Pit basemat is now completed, work on the retaining walls advances, and 385 out of 493 concrete plinths have been cast. Photo: ITER Organization
Three-and-a-half months were necessary to complete the 1.5 metre-thick Seismic Pit basemat. The works underwent regular inspection: both internal audits and those conducted by the French nuclear safety regulators (ASN) have confirmed the good quality of the works. Photo: ITER Organization
The 140 "oriented plinths" in the centre of the basemat are the last to be poured: these plinths will directly support the 23,000-ton ITER Tokamak. Photo: F4E
The surface elevation, roughness (guaranteeing that the second-phase concrete will adhere perfectly) and height of the reinforcement at the top of the plinth are verified before each bearing is installed. Tolerance for these measurements is in the range of one millimetre. Photo: F4E
In the centre of the Tokamak Pit, it's easy to distinguish the "spokes" of seismic reinforcement that will bear the weight of the ITER device. Photo: ITER Organization
Concrete pouring for the Seismic Pit basemat progresses at a rhythm of one slab per week. The twenty-one slabs, once completed, will form a single, smooth surface. Photo: ITER Organization
Late November 2011, the concrete slab at the bottom of the Tokamak Pit is 80 percent complete: 14,000 out of 17,000 cubic metres of concrete have been poured since August. Photo: ITER Organization
One and a half metres thick at their base, the retaining walls will form a box around the foundation slab of the Tokamak Pit and the anti-seismic pillars and bearings. Photo: F4E
Nearly 6,000 cubic metres of concrete will be necessary for the retaining walls of the Seismic Pit. Work began mid-October and will continue through February 2012. Photo: ITER Organization
Cohesion between the plinth, second-phase concrete and mortar is essential to achieve the monolithic behaviour of the structure. Image: ITER Organization
The bearing is placed on top of a height adjustment system that enables the position, level and inclination of the bearing to be fine tuned. Topographical checks are performed before plinth and bearing are ready to receive the second-phase concrete. Photo: F4E
The first five-metre vertical segment of retaining wall has been poured in this corner of the Seismic Pit. At this level, the retaining walls are 1.5 metres thick. Photo: F4E
Workers guide just the right dose of concrete onto the top of each seismic pillar; this "second-phase" concrete will join the pillar to the seismic bearing. All over the Seismic Pit, this operation is being repeated 493 times. Photo: F4E
Looking south over the football-pitch-sized Seismic Pit. To the right: the cleared area for the Hot Cell Facility. To the left: the long red line of the Poloidal Field Coils Winding Facility. Photo: ITER Organization
The seismic basemat—the white "floor" of the Tokamak Pit—is filled in progressively. Along the western wall, work has begun on the retaining walls (lower left). Photo: ITER Organization
493 seismic pads will protect the ITER machine and the Tokamak Complex (Tokamak, Diagnostic and Tritium Buildings). This CAD-generated image shows the exact configuration of the pads on the 1.5-metre-thick Seismic basemat. Image credit: ITER Organization
The lower five metres of retaining wall will be the thickest. From one and a half metres at its base, the wall will taper to 0.5 metres at its highest point. Photo: ITER Organization
The 15-metre-tall retaining walls will be poured in three 5-metre stages; the lowest five-metre segment, seen framed out here, is 1.5 metres in width. Space between the upper segments of the concrete retaining wall and the rock face will be filled in with gravel and sand and compacted. Photo: F4E
The "crawl space" between the Seismic Pit basemat and the Tokamak Complex basemat will permit regular inspection of the seismic pads, which are designed to last well beyond the lifetime of ITER. Photo: F4E
In order to cure the "second-phase" concrete below each seismic bearing, workers use a local heating unit to maintain the concrete temperature around 30 degrees centigrade. Photo: F4E
Atop the concrete plinth, the seismic pad has been positioned and cemented into place. When completely dry, the newer concrete will take on the exact colour of the older concrete. Photo: ITER Organization
On the ITER site, seismic isolation pads await installation. In the months to come, the pads will be installed at a rhythm of approximately ten per week. Photo: ITER Organization
Seismic Pit basemat pouring continues in September 2011. The areas framed out by wooden walkways are next in line to be poured. Photo: ITER Organization
Sandwiched between the Seismic basemat and the Tokamak Complex basemat
Each 90 x 90 cm pillar (1.7 metres tall) will support a seismic isolation pad made of alternate layers of metal and rubber. The floor of the Tokamak Complex will rest on a total of 493 pillars. Photo: ITER Organization
On one completed corner of the Seismic Pit basemat, the concrete pillars, or plinths, of the seismic isolation system take shape. Photo: ITER Organization
This portion of the Seismic Pit basemat has dried, and second phase work begins: the pouring of the 493 concrete plinths that will support the anti-seismic bearings of the Tokamak Complex. Photo: ITER Organization
Pouring activities begin in the north-west corner of the Seismic Pit; in the opposite corner, preparations are underway for the second day's pour planned for the following week. Work will continue—first one side, then the other—in a counter-clockwise direction until the edges of the basemat are filled in. Photo: F4E
The two concrete batching plants on site are each capable of providing a flow of 100 m³ per hour. One plant serves as a backup to the other, ensuring that no disruption occurs in supply during the 12-hour pouring days. Photo: F4E
Some 800 m³ of concrete are poured on the first day. This 12-hour operation will have to be repeated 21 times over the next 3 months to complete the basemat of the Seismic Pit. Photo: F4E
The three buildings of the Tokamak Complex will share a single foundation: having a monolithic structure avoids the relative displacement of process pipes crossing the buildings. Photo: F4E
Sitting atop the Seismic Pit basemat, 493 of these 1.7 metre concrete columns, or "plinths," will support the seismic pads. These, in turn, will support the basemat of the Tokamak Complex—the actual "floor" of the installation. Photo: F4E
Workers install metal "chairs" for structural stability between the lower and higher levels of crisscrossed reinforcement. Foundation pouring will begin in August. Photo: F4E
The vertical reinforcement bars standing five metres high against the rock face will be part of the lower retaining wall of the Seismic Pit. Photo: F4E
Workers measure the exact spacing of the rebar used on the floor of the Seismic Pit. Regular spacing and tying off the bars so that they remain in position are important to achieving the desired strength of the completed concrete. Photo: F4E
Metal "chairs" are positioned on the bottom layer of crisscrossed rebar. Steel reinforcement will be built up to 1.5 metres before foundation pouring begins. Photo: F4E
One of four pedestrian access staircases into the Tokamak Complex Seismic Pit. Some seventy workers involved with foundation work go up and down these staircases daily. Photo: ITER Organization
On top of a five to ten centimetre layer of "blinding concrete," workers position steel rebar in June 2011. Some 3,400 tons of rebar is planned for the first level of foundations: the Tokamak Complex Seismic Pit basemat. Photo: F4E
Work progresses in the neighbouring Hot Cell Facility area
Finishing touches to the Hot Cell Facility area before work begins on the blinding layer of concrete, reinforcement and foundation work, just like in the Tokamak Complex area seen beyond. Photo: F4E
The first level of steel rebar is positioned on the floor of the Seismic Ísolation Pit. Reinforcement for the Seismic Pit basemat will be 1.5 metres high. Photo: AIF
A thin layer of concrete is spread to create a clean and flat surface upon which to begin foundation operations. In the Seismic Pit, 550 m³ of concrete were necessary. Photo: ITER Organization
.jpg)
.JPG)
.jpg)
.JPG)
.JPG)
.JPG)
.JPG)
.jpg){kind=link}
.JPG){kind=link}
.jpg){kind=link}
.JPG){kind=link}
.JPG){kind=link}
.JPG){kind=link}
.JPG){kind=link}