India Fusion Program (SST-1, ITER-India)

Overview

The Indian Fusion Program represents a comprehensive, multi-decade national strategy to develop fusion energy. Administered primarily by the Institute for Plasma Research (IPR) under the Department of Atomic Energy (DAE), the program pursues a dual-track approach: developing indigenous capabilities through domestic experimental devices and contributing to the global effort as a full partner in the ITER project. The program's core objectives are to build a domestic scientific and industrial ecosystem for fusion technology, conduct research on high-temperature plasma physics, and prepare for the construction of a future Indian demonstration power plant (DEMO).

India's participation in ITER is a cornerstone of its strategy. As one of the seven member entities, India is responsible for delivering critical, high-technology components in-kind, representing approximately 9% of the project's construction cost. This involvement provides Indian scientists, engineers, and industries with direct experience in building and integrating fusion reactor-scale systems. Domestically, the program is anchored by two tokamaks: the ADITYA-U, a medium-sized machine for fundamental plasma physics studies, and the Steady State Superconducting Tokamak (SST-1), which serves as a testbed for the long-pulse, steady-state operational regimes essential for future power plants.

Physics and Mechanism

The scientific and engineering focus of the Indian program is centered on the tokamak concept of magnetic confinement fusion. The program's research addresses key physics and technology areas required for a steady-state fusion reactor.

Plasma Physics: Research on the ADITYA-U tokamak investigates plasma transport, magnetohydrodynamic (MHD) instabilities, and plasma-wall interactions. A key area of study is the control of disruptions and runaway electrons, which are critical for the safe operation of large devices like ITER. Experiments also focus on plasma heating techniques, including Electron Cyclotron Resonance Heating (ECRH) and Ion Cyclotron Resonance Heating (ICRH), and the development of advanced plasma diagnostics.

Superconducting Magnet Technology: The SST-1 is a pioneering device for the program, being one of the world's first tokamaks to feature a fully superconducting magnet system (both toroidal and poloidal field coils) using Niobium-titanium (NbTi) conductors. The design and operation of SST-1 provide invaluable experience in the complex engineering of large-scale cryogenics, high-current power systems, and quench detection and protection for superconducting magnets—technologies directly transferable to ITER and future reactors.

High-Heat-Flux Components: A major engineering thrust is the development of plasma-facing components (PFCs) capable of withstanding the extreme heat loads of a reactor. The program has developed expertise in manufacturing and testing divertor components, first wall panels, and limiters. This includes work on materials like tungsten and copper alloys and the development of robust cooling technologies, such as the swirl-tube concept for enhanced heat transfer.

Cryogenics and Vacuum Systems: India's contribution to ITER includes the world's largest cryostat, a 3,850-tonne stainless steel vacuum vessel that encloses the entire tokamak. The design, fabrication, and on-site assembly of this component have significantly advanced India's industrial capabilities in large-scale manufacturing, precision welding of thick plates, and ultra-high vacuum technology. The program also develops and operates large helium cryoplants required to cool the superconducting magnets to 4.5 K.

Historical Development

India's formal engagement with plasma physics began in the late 1970s. The Plasma Physics Programme (PPP) was initiated at the Physical Research Laboratory (PRL) in Ahmedabad.

1982: The Government of India launched a dedicated national program in plasma physics.
1986: The Institute for Plasma Research (IPR) was established as an autonomous institute under the DAE, formalizing the national effort.
1989: The first indigenous Indian tokamak, ADITYA, achieved its first plasma. ADITYA was a conventional, medium-sized tokamak designed to build domestic expertise in tokamak operation, control, and diagnostics.
1990s: Recognizing the need to investigate steady-state operation, a key requirement for a fusion power plant, IPR began the design of the Steady State Superconducting Tokamak (SST-1). This was an ambitious step, placing India among a small group of nations developing superconducting tokamak technology.
2005: India formally joined the ITER project as a full member. The domestic agency, ITER-India, was established at IPR to manage the nation's contributions.
2005-2012: Construction and assembly of the SST-1 tokamak faced significant technical challenges, particularly with the superconducting magnet joints and the performance of the cryoplant, leading to delays.
2013: SST-1 achieved its first plasma, a major milestone for the domestic program.
2016: The ADITYA tokamak was upgraded with a shaped vacuum vessel and enhanced power systems, becoming ADITYA-U. This upgrade enabled the study of diverted plasma configurations and higher-performance plasma scenarios.

Current Status

As of 2026, the Indian Fusion Program is actively advancing on both its domestic and international fronts.

ITER Contributions: ITER-India has successfully delivered a significant portion of its in-kind procurement packages. The massive base and lower cylinder of the cryostat have been installed in the ITER pit in France. Fabrication and delivery of other components, including cryolines, vacuum vessel cooling pipes, and diagnostic systems, are ongoing. According to a 2024 report by the ITER Organization, India's contributions are progressing, with the final cryostat sections scheduled for delivery and on-site welding. This industrial-scale manufacturing effort is a primary focus of the program.

SST-1 Operations: The SST-1 tokamak is in an operational phase focused on achieving its design goal of 1,000-second long-pulse discharges. The machine serves as a crucial testbed for validating the performance of its superconducting magnets and high-heat-flux divertor components in steady-state conditions. The experimental campaigns are aimed at integrating plasma heating and control systems for stable, long-duration operation, providing data relevant to ITER's non-inductive current drive scenarios.

ADITYA-U Experiments: The ADITYA-U tokamak continues to be a workhorse for fundamental plasma physics research and diagnostic development. Recent experimental campaigns have focused on disruption mitigation studies using pellet injection and understanding the physics of plasma transport in shaped configurations. It also serves as a vital training facility for the next generation of Indian plasma physicists and engineers.

Notable Implementations

Institute for Plasma Research (IPR): Located in Gandhinagar, Gujarat, IPR is the nerve center of India's fusion program. It hosts the ADITYA-U and SST-1 tokamaks and is the parent organization for ITER-India. IPR conducts a broad spectrum of research, from fundamental plasma theory to applied fusion engineering.
ITER-India: As the Indian Domestic Agency for ITER, this body is responsible for managing the procurement packages assigned to India. It acts as the interface between the ITER Organization and Indian industry, overseeing the design, manufacturing, and delivery of components like the cryostat, in-wall shielding, and various heating and diagnostic systems.
SST-1 (Steady State Superconducting Tokamak): A key domestic facility, SST-1 is a large-aspect-ratio (R=1.1 m, a=0.2 m) tokamak designed for long-pulse (up to 1,000 s) operation. Its primary mission is to test and validate technologies for steady-state fusion reactors, particularly superconducting magnets and actively cooled plasma-facing components.
ADITYA-U: An upgraded version of India's first tokamak, ADITYA-U (R=0.75 m, a=0.25 m) is a medium-sized machine with a divertor configuration. It is used for research on plasma confinement, stability, and plasma-wall interaction, and serves as a testbed for new diagnostics before their potential deployment on larger machines.

Open Challenges

The Indian program faces several scientific and engineering challenges that are common to the global fusion effort, as well as some specific to its national context.

Achieving Full Performance on SST-1: A primary challenge is the full commissioning of SST-1 to its design parameters, specifically achieving stable 1,000-second plasma discharges. This requires overcoming technical hurdles related to the integration of heating systems, plasma control, and heat removal from the divertor in a steady-state environment. The reliability of the complex cryogenic and magnet systems remains a key focus.
Industrial Scale-Up: While the ITER project has catalyzed significant growth in India's high-tech manufacturing capabilities, maintaining and expanding this industrial base for future fusion projects is a challenge. Ensuring consistent quality control and meeting the stringent technical specifications for components like the tritium breeding blanket for a future DEMO will require sustained investment and policy support.
Materials Science: Like all fusion programs, India faces the challenge of developing and qualifying materials that can withstand the harsh neutron environment of a fusion power plant. This includes structural materials for the vacuum vessel and breeding blanket, as well as plasma-facing materials for the divertor.
Defining the Post-ITER Path: The program needs to solidify a long-term strategic plan for its post-ITER activities. This includes deciding on the design and timeline for a domestic DEMO or a Component Test Facility (CTF) that would bridge the gap between ITER and a commercial power plant. Securing the necessary national funding for such a large-scale project is a critical political and economic challenge.

Outlook

The 5-15 year trajectory for the Indian Fusion Program is shaped by the timelines of its major projects.

In the near term (5 years), the primary focus will be on completing all of India's in-kind contributions to the ITER project, culminating in the final assembly of the cryostat. Concurrently, the SST-1 program will aim to demonstrate routine, stable long-pulse plasma operation, providing critical operational data and serving as a platform for testing DEMO-relevant technologies. ADITYA-U will continue its role in fundamental physics research and workforce development.

Looking out 10-15 years, as ITER begins its operational phases, the Indian program will transition to exploiting its access to this world-leading facility. Indian research teams will participate in ITER experiments, gaining experience with burning plasma physics. During this period, the conceptual and engineering design activities for India's own next-step device, likely a DEMO-class machine, are expected to intensify significantly. The success of the SST-1 program and the industrial lessons learned from ITER will be crucial inputs for the design and eventual approval of this future national project, which will aim to demonstrate net electricity production and a closed tritium fuel cycle.

References

Progress of the Indian domestic agency for the ITER project: ITER-India — Fusion Engineering and Design (2015)
First plasma in the Indian tokamak ADITYA — Nuclear Fusion (1991)
Recent results from the ADITYA-U tokamak — Nuclear Fusion (2021)
Present Status of SST-1 — IAEA Technical Meeting on Steady State Operation of Magnetic Fusion Devices (2017)
ITER-India: In-kind contributions to the ITER project — Journal of Physics: Conference Series (2007)
The Indian programme on the development of Reduced Activation Ferritic Martensitic (RAFM) steel for fusion reactor applications — Nuclear Fusion (2007)
ITER Cryostat — ITER Organization
Institute for Plasma Research: Annual Report 2022-2023 — Institute for Plasma Research (2023)