The ITER Organization has contracted Larsen & Toubro (L&T) to perform crucial assembly and installation tasks for the tokamak's main containment structures. The scope of work includes the on-site assembly of 54 cryostat and vacuum vessel ports, installation of complex internal shielding components, and subsequent high-vacuum leak testing of the assembled systems. This contract represents a significant step in the machine assembly phase, transitioning from component manufacturing to the complex integration of subsystems within the tokamak pit. L&T has a long-standing relationship with the project, having previously fabricated the cryostat base, lower cylinder, and upper cylinder at its Hazira facility. Source: ITER

The contract focuses on the intricate interface between the cryostat and the vacuum vessel, the primary steel container that houses the fusion plasma. L&T will be responsible for installing the embedded shielding, which is designed to protect the superconducting magnets from neutron flux and thermal loads. The work also involves the delicate process of welding the port stubs to the vessel sectors, a task requiring extreme precision to maintain the structural integrity and vacuum-tightness necessary for plasma operations. These ports provide essential access for remote handling, diagnostics, heating, and vacuum systems, making their correct installation fundamental to the machine's functionality. Source: ITER

The contract focuses on the intricate interface between the cryostat and the [vacuum vessel](/glossary/vacuum-vessel), the primary steel container that houses the fusion plasma.

This award underscores the industrial-scale manufacturing and construction challenges inherent in the ITER project. The cryostat, which L&T helped construct, is the largest stainless-steel high-vacuum pressure chamber ever built, measuring 30 meters in diameter and height. The successful integration of the vacuum vessel ports within this structure is a critical-path activity for the project's timeline. The work requires advanced welding techniques and metrology to manage tight tolerances and material properties under the extreme thermal and mechanical stresses expected during operation, from cryogenic temperatures for the magnets to the high heat loads from the plasma. Source: ITER

Ultimately, the integrity of the vacuum vessel and its associated systems is paramount for achieving the project's primary scientific goal: producing 500 MW of fusion power from 50 MW of heating power, for a plasma energy gain (Q_plasma) of 10. This level of performance is intended to demonstrate the scientific and technological feasibility of fusion energy on a power-plant scale. The successful execution of this assembly contract by L&T is a prerequisite for the first plasma experiments and the subsequent deuterium-tritium (D-T) campaign designed to achieve this milestone in fusion science. Source: ITER