ITER NEWSLINE
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Crane vs crane
As action will soon move toward the adjoining Assembly Building area, two of the four cranes that operated over the Pit were dismantled this week.
With the 493rd and final antiseismic pad
installed and the retaining walls finalized, a relative quiet has settled over the ITER Tokamak Pit.
As action will soon move toward the adjoining Assembly Building area, two of the four cranes that operated over the Pit were dismantled this week.
Crane C4, located on the northwest corner of the work site, was taken down on Monday 23 April. Two days later, a similar operation was performed on crane C3 in the south corner.
Dismantling a 50-metre-high tower crane is a delicate and spectacular operation. First, it's necessary to remove the concrete counterweights that balance the 65-metre-long boom. Once the 15 tonnes of counterweights have been lowered, crane dismantling specialists climb into the boom to begin the detachment process.
''The only real difficulty,'' explains a crane dismantling specialist ''is the wind. Also ... finding enough room to lay the boom on the ground ...''
With the boom hanging solidly from a mobile crane, specialists can begin unscrewing the large bolts that connect the 14.7-tonne boom to the tower. Once freed, the lifting crane slowly moves it down to the ground where it will await further dismantling.
"The only real difficulty," explains dismantling specialist Armand Depit of MAGSUD, based in Aix-en-Provence, "is the wind. Also ... finding enough room to lay the boom on the ground ..."
On Wednesday, as crane C3 was dismantled, the air was perfectly still on the ITER platform and there was still plenty of room—although not for long—in the Tokamak Pit work site perimeter.
The dismantling operation went smoothly and took less than one hour and a half.
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