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50,500 plates, each differentSince late 2015, segments for the ITER cryostat's base section and lower cylinder have been successively forged, machined, finalized, shipped to the ITER construction site, and assembled and welded in the onsite Cryostat Workshop.
Another ITER-related activity is underway on Larsen & Toubro's Hazira campus: the assembly of thousands of steel plates that vary in size from "pocket-book" to "road-atlas."
ITER will require 50,500 such plates, all procured by ITER India and assembled into in-wall shielding blocks. Filling 55%of the space between the double walls of the vacuum vessel, the blocks will provide shielding from neutron radiation for components situated outside the vacuum vessel (such as the magnets) and contribute to improving the confinement of the plasma's fast particles.
Like carefully aligned pieces of a giant puzzle, thousands of plates, each different in size, shape and weight, cover the ground of a dedicated temperature-controlled workshop.
Manufactured by Avasarala Technologies Limited (ATL) and Larsen & Toubro Ltd, the plates are assembled into blocks—up to 11 plates per block. At the far end of the workshop, some 160 assembled blocks (representing close to 500 plates), having passed factory acceptance testing and are ready to be shipped to Korea, where they will be inserted into the vacuum vessel sectors being manufactured there.
Guided by Anil Parab, the Executive Vice President of Larsen & Toubro's Heavy Engineering division (second from left), ITER Director-General Bernard Bigot visits Larsen & Toubro's Hazira facility on 23 October. Also present are Johannes Schwemmer and Kijung Jung (respectively head of the European and Korean Domestic Agencies) and by representatives of the Indian Domestic Agency.
05 November 2018Download
The most spectacular of all the facilities in the Larsen & Toubro Hazira complex is the one-kilometre long foundry that produces 40,000 tonnes of finished forgings annually. Among them are the steel ingots that are pressed and machined into ITER cryostat segments.Download
Despite Larsen & Toubro's extensive experience in manufacturing for the nuclear and space industries, new processes and techniques had to be specifically developed for the welding of the cryostat segments. Pictured here: the welding of two segments for the top lid.Download
As work is being finalized on a tier-two segment of the cryostat upper cylinder, T-ribs for the top lid are being prepared for welding. The top lid is made of 12 segments that each comprise ribs, knuckles and a crown.Download
These tier-two upper cylinder segments are being packed and conditioned for the long journey to the ITER site. In the on-site Cryostat Workshop, Larsen & Toubro contractors will weld tier-one segments first, then position tier-two segments on top. Upper cylinder segments will begin arriving at ITER in March 2019.Download
The 655-tonne top lid will be the last of four cryostat sectors to leave the Larsen & Toubro factory (in segments). Before series manufacturing began, a prototype segment was manufactured in order to check potential profile distortions. All 12 top lid segments will be ready for dispatch in the summer of 2019.Download
On their way back from lunch, workers at Larsen & Toubro's Hazira faility pass by ongoing works for the ITER cryostat inside Medium Fabrication Shop #4.Download
A small-size mockup of the ITER cryostat sits in front of an upper cylinder segment ready for dispatch. Once assembled in the ITER Tokamak Pit, the 30-metre-wide cryostat will represent 3,850 tonnes (approximately 16% of machine weight).Download
The quality control team inspects a 120-millimetre-thick upper cylinder flange. As a vacuum chamber, the leak-tight quality of all welds must be irreproachable.Download
"Submerged arc welding" (SAW) is the technique used in the welding of these two top lid plates. The molten weld and the electric arc zone are protected from oxydation by being "submerged" under a flux of small grains of carbon, manganese and silicon. The "HZMC" on the welder's overalls stands for Hazira Manufacturing Complex.Download
In-wall shielding plates--assembled into blocks--will fill 55% of the space between the double walls of the vacuum vessel. Their role? To shield components outside the vacuum vessel from the neutrons generated by the fusion reaction and contribute to the confinement of the plasma's fast particles. The ITER machine will require 50,500 such plates, each unique in shape, size and weight.Download
Due to the geometry of the vacuum vessel, the in-wall shielding plates (and hence the blocks) are unique. Once assembled, the blocks are shipped to the vacuum vessel manufacturers in Korea and Europe.Download
It takes between one and eleven in-wall shielding plates to form a block. In late October, some 160 blocks (representing close to 500 plates) were ready to be shipped from the Hazira facility to the Korean manufacturer in charge of producing four vacuum vessel sectors for ITER.Download