What a difference ten days make
19 Jun 2017
There was a time when progress in Tokamak Complex construction was easy to follow. Excavation in 2010; the creation of the ground support structure and seismic foundations from 2010 to 2014; the achievement of the concrete "floor" (the B2 slab) in 2014; and finally the erection of the first levels of the Tritium, Tokamak and Diagnostics buildings—each operation appearing to the non-specialist as having obvious and clearly defined parameters*.
On 9 June, one wonders what to make of this giant "wool ball," half concrete and half steel.
Things began to change with the construction of the Tokamak bioshield, the massive circular structure at the centre of the Tokamak Complex. As intricate formwork was installed all around to match the advancing work, what was happening inside the "Pit" became harder and harder to ascertain. Seen from one of the worksite cranes on 9 June, the complexity around the bioshield seems to reach an all-time high: what to make of this giant "wool ball," half concrete and half steel?
Ten days later, with a large part of the formwork and scaffolding removed, the details of the Tokamak bioshield have at last become easier to "see" for the non-specialist. The two above-ground levels are now clearly defined: Level 1 (L1) can be distinguished by the oval openings created for the neutral beam injection system; Level 2 (L2) has regular 4-by-4-metre penetrations that will allow system equipment such as magnet feeders, remote handling, heating and diagnostics to reach the machine.
In some places, steel rebar is already in place for Level 3 (L3), which will rise eight metres above L2. Contrary to L1 and L2 it will be a "blind wall," with no penetrations whatsoever.
Ten days later, with a large part of the formwork and scaffolding removed, the details of the Tokamak bioshield have at last become easier to "see" for the non-specialist.
Looking down into the "arena" we can see new steel structures and a small overhanging workshop that are in place for the installation of a temporary cap that will completely remove the basement levels inside the bioshield from our view. Its purpose is to protect workers at the B2 level as they create the reinforced concrete crown that will support the cryostat and—ultimately—the vacuum vessel.
As a result, this photo offers one of the last opportunities to peek into the depths of the "well" that will accommodate the machine.
*Retrace the history of Tokamak Complex construction on the Building ITER section of our website (Construction Archives).