Manufacturing

In the cradle of the cryostat

On the northwestern coast of India, facing the Arabian Peninsula, Hazira is one of the subcontinent's major industrial hubs. Under the still-blazing autumn sun, the landscape is one of refineries, shipyards, power plants, storage tanks and endless queues of oil and container trucks. It is here, at the Larsen & Toubro Ltd manufacturing complex, that a critical ITER component is taking shape.

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A formidable industrial venture that began in 2015 is nearing its end. At the Larsen & Tourbo Hazira manufacturing complex, work is underway on the two last orders the company is filling for the ITER cryostat: segments of the 430-tonne upper cylinder and top lid.
Between ocean and mangrove, amidst a world of dust and rust, the Larsen & Toubro Ltd "campus" is like an oasis of green and cool. In the mid-1980s, the mammoth Indian conglomerate drained close to one thousand acres of marshland to establish this multi-facility complex.
 
Thirty years later, the place is a unique aggregation of manufacturing facilities that turn out offshore oil platforms at the rate of 10 to 12 per year and manufacture ships, submarines, tanks, giant boilers and turbines ...
 
At one kilometre long, the west campus' special steels and forging facility is one of the largest in the world. In an atmosphere that mixes space-age technology with a 19th century steel mill atmosphere, "manipulators" the size of freight train locomotives slowly move amidst giant furnaces and massive steel ingots laid to cool on sand beds. The facility produces more than 40,000 tonnes of finished forgings annually.
 
Across the road on the east campus, administrative buildings, fabrication facilities, workshops and port installations cover close to one hundred hectares.
 
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Final dimensional inspection is being conducted on an upper cylinder sector for the ITER cryostat. Seven segments are packed and ready for dispatch; another two are undergoing finishing works and inspections.
This environment is the cradle of the ITER cryostat, the largest of the Tokamak's components—a giant, leak-tight cylinder 30 metres high and 30 metres in diameter that will act as a "thermos" to insulate the ultra-cold magnets from the environment.
 
From humble beginnings in the form of ingots that look strangely like truncated Doric columns, to the shining stainless steel segments ready to be shipped to the ITER site, it all happens here.
 

50,500 plates, each different

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.

Since 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.
 
In December 2013, as the first mockups were produced to demonstrate and validate welding and manufacturing sequences and techniques, Madhukar Kotwal, then president of Larsen & Toubro Heavy Engineering, told Newsline that despite the company's accumulated experience in manufacturing nuclear and space components, the ITER cryostat was so "special" that it presented unprecedented challenges, both technical and organizational.
 
Five years later, the challenges have been met and overcome and the manufacturing of the segments for the "huge assembly" of the ITER cryostat is nearing its end.
 
In the east campus, inside Medium Fabrication Shop #4, work is now underway on the last two orders that Larsen & Toubro is filling for the ITER cryostat: seven segments of the 430-tonne upper cylinder are packed and ready for dispatch; another two are undergoing finishing works and inspections; a segment prototype for the 655-tonne top lid is in the last stage of fabrication; and various tasks are being performed on the "ribs," "flanges," "knuckles," and "crown" that make up a top lid segment (see further technical detail in the photo gallery below.)
 
Although 7,000 kilometres and three and a half time zones stand between the Larsen & Toubro teams in Hazira and those on the ITER worksite, communication between them is constant. "We have a conference call every single working day," says Chirag Patel, the Larsen & Toubro project manager for the ITER cryostat and in-wall-shielding (see box). "And we will soon be implementing Wi-Fi-connected viewing goggles that will enable us to have a better visual assessment of the ongoing works in the Cryostat Workshop at ITER."
 
In the summer of 2019, the 12 top lid segments will be shipped to ITER, marking the end of a formidable industrial venture that has spanned two continents and involved hundreds of specialists in both Hazira and at the ITER site in Saint-Paul-lez-Durance.
 
Click here to watch the "Made in India" video.