On June 26, 2026, India’s Department of Atomic Energy opened a facility in Kalpakkam that produces hydrogen using heat from a nuclear reactor. With this, India is taking a new step toward large-scale, fossil-free hydrogen and aims to scale up the technology later.
India has commissioned a pilot facility that produces hydrogen using heat from a fast breeder reactor — a world first that puts the role of nuclear energy in the hydrogen chain back in the spotlight. On the campus of the Indira Gandhi Centre for Atomic Research, the process runs alongside the Fast Breeder Test Reactor, a 40 MW thermal reactor that has been operational since 1985. Instead of electricity, the facility uses the copper-chlorine cycle, which operates at around 530°C and is meant to keep the CO₂ footprint per kilogram of hydrogen low. The promise of fossil-free hydrogen is getting closer, putting India’s decades-long nuclear strategy around self-reliance and sustainability more prominently in the spotlight.
A world first in Tamil Nadu
Kalpakkam is located on the coast of Tamil Nadu, about 70 kilometers south of Chennai. The new facility has been set up as “pilot industrial” — a demonstrator meant to show that the technology also runs stably and safely outside the lab.
Several Indian nuclear institutes are involved in the project, including the Bhabha Atomic Research Centre (BARC) in Mumbai and IGCAR in Kalpakkam. They are aiming for a fully domestically developed chain, from reactor to process facility and instrumentation. That also makes this an industrial policy project.
How the technology works
The copper-chlorine cycle is a 4-step thermochemical process, with intermediate products such as CuCl and Cu2OCl2. Only 1 step requires a bit of electricity; the rest runs on process heat.
The process operates at around 530°C, considerably lower than alternatives such as the sulfur-iodine cycle, which requires 850 to 900°C. That lower temperature increases the number of reactor concepts that can be coupled with hydrogen production. In Kalpakkam, this involves a sodium-cooled fast reactor, a type that can specifically deliver high-temperature heat.
The emissions in this pilot are calculated at 0.5 to 1.35 kg CO₂ per kg H₂, depending on process conditions. By comparison, the dominant global route, steam methane reforming, comes in at 10 to 12 kg CO₂ per kg of hydrogen.
For the Cu-Cl route, an efficiency of 30 to 40 percent is cited, compared to 4 to 6 percent for the combination of solar PV and electrolysis. The estimated cost still varies widely: $1.28 to $15.56 per kg, or roughly €1.1 to €13.3 per kg.
According to its own statements, BARC worked on industrialization for more than 15 years, with an emphasis on corrosion-resistant materials, heat exchangers, and measurement and control technology for acids, molten salts, and high temperatures. The chemical basis is older: the Cu-Cl cycle was co-developed in the 2000s by Atomic Energy of Canada Limited and the US-based Argonne National Laboratory. This is the first time an attempt has been made to run the entire chain as a factory.
India’s nuclear strategy
The hydrogen demonstrator builds on an older plan: nuclear physicist Homi Jehangir Bhabha’s three-stage program from the 1950s. The impetus was resource scarcity. India is estimated to hold 1 to 2 percent of the world’s uranium reserves, but 12 to 25 percent of its thorium reserves. The long-term goal is therefore a thorium-uranium-233 cycle.
Stage 2 centers on fast breeder reactors. A milestone was the first criticality of the Prototype Fast Breeder Reactor (PFBR) on April 6, 2026 — a 500 MWe reactor designed by IGCAR and built by BHAVINI. With a commercial fast breeder, India joins a small club: after Russia (BN-600 and BN-800), few countries operate this at an industrial scale.
Other countries, by contrast, pulled the plug on similar efforts. France stopped the Astrid program in 2019, Japan shut down Monju after years of problems, and the US ended the Clinch River project in the 1980s. India is now demonstrating both a fast reactor line and a hydrogen coupling, putting the debate over nuclear heat back on the map.
Legislation has also been updated. In 2025, the SHANTI Act (Sustainable Harnessing and Advancement of Nuclear Energy for Transforming India) was passed, modernizing the framework and, for the first time, enabling regulated private participation alongside international cooperation. At the same time, BARC is developing its own SMR designs: the BSMR-200 (200 MWe) and the SMR-55 (55 MWe).
In addition, there’s a separate hydrogen reactor project: a 5 MWth High-Temperature Gas-cooled Reactor specifically intended for hydrogen production, planned for the BARC campus in Vizag (Andhra Pradesh). This combination of fast reactors, SMRs, and an HTGR points to a broad technology portfolio, with hydrogen as an explicit end product.
What does this mean for hydrogen production?
Next to the PFBR on the same campus, a demonstrator with a capacity of 3,000 normal liters of hydrogen per hour is planned. This moves the project from lab-scale proof to a chain involving a new reactor.
Ajit Kumar Mohanty, Secretary of the Department of Atomic Energy and Chairman of the Atomic Energy Commission, explicitly linked the demonstrator to scaling up: “The integration of nuclear energy with emerging clean energy technologies, such as hydrogen production, represents a strategic pathway toward a sustainable energy future.” Nuclear energy provides process heat in addition to electricity, and that heat is exactly what’s in short supply in an industry seeking to electrify.
The International Energy Agency (IEA) estimated global hydrogen production in 2023 at 97 million tons, of which less than 1 percent was low-carbon. The same analysis projects an order of magnitude of 660 million tons per year by 2050, driven mainly by industry.
An example the world can follow?
The EU is building hydrogen markets with strict sustainability definitions, while nuclear energy remains politically divisive and the discussion around “nuclear” hydrogen remains sensitive in several member states. The Netherlands is caught in the middle of this, with plans for new nuclear plants alongside a hydrogen agenda for industrial clusters.
The Indian demonstrator mainly shows that the core question is shifting from electricity to heat: who can reliably deliver high-temperature heat without CO₂, at predictable cost. The next test will be the construction and operation of the 3,000-normal-liter-per-hour demonstrator next to the PFBR, plus the planned 5 MWth HTGR project in Vizag. If continuity and material durability hold up there, an exportable blueprint could emerge — one that would also make the debate in Europe more technically concrete.
