India Splits Water With Reactor Heat: World's First Copper-Chlorine Nuclear Hydrogen Plant Opens at Kalpakkam

India has switched on what its nuclear establishment is calling a world first. On 26 June 2026, the Department of Atomic Energy (DAE) inaugurated a hydrogen production facility that uses the Copper-Chlorine (Cu-Cl) thermochemical cycle driven by nuclear process heat drawn from the Fast Breeder Test Reactor (FBTR) at the Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam, in Tamil Nadu.

The plant was inaugurated by Ajit Kumar Mohanty, Secretary of the DAE and Chairman of the Atomic Energy Commission, in the presence of Sreekumar G. Pillai, Director of IGCAR. Officials described it as the first facility anywhere to produce hydrogen through the Cu-Cl cycle using heat from a nuclear reactor.

Splitting water with heat, not electricity

Most "green" hydrogen today is made by electrolysis — passing electricity through water to break it into hydrogen and oxygen. Thermochemical cycles take a different route: they use heat to drive a closed loop of chemical reactions that ultimately split water, recycling the working chemicals so that only water is consumed and only hydrogen and oxygen come out.

The Copper-Chlorine cycle is one such loop, and it is attractive because it can run at moderate temperatures compared with rival thermochemical routes, which makes it a good match for the grade of heat a nuclear reactor can supply. The Cu-Cl process used at Kalpakkam was developed indigenously by the Bhabha Atomic Research Centre (BARC) in Mumbai; the new facility serves as a technology demonstrator to validate the chemistry at a working scale using the FBTR as the heat source.

Why pair it with a reactor

A nuclear reactor produces vast quantities of high-grade heat continuously, day and night, regardless of weather. Channelling some of that heat directly into a thermochemical hydrogen plant — rather than first converting it to electricity and then back into chemical energy — sidesteps the efficiency losses of electrolysis and can, in principle, produce hydrogen at large scale without burning fossil fuels and without carbon emissions.

That is the long-term promise the DAE is chasing: carbon-free hydrogen as an industrial feedstock and fuel, produced by coupling India's reactor fleet to thermochemical plants. The FBTR demonstrator is a step toward proving the concept works outside the laboratory.

Where it fits in India's hydrogen push

India has built much of its clean-hydrogen ambition around the National Green Hydrogen Mission, which leans heavily on electrolysers powered by renewable electricity. The Kalpakkam facility opens a parallel, nuclear-powered pathway — one that does not compete for the same solar and wind capacity and that can run at high capacity factors. It also slots neatly into the second stage of India's three-stage nuclear programme, anchored at Kalpakkam, where the FBTR and the larger Prototype Fast Breeder Reactor are central to the country's long-term energy plans.

A demonstrator, not yet a factory

It is important to keep the scale in perspective: this is a technology demonstrator meant to validate the Cu-Cl process and its integration with reactor heat, not a commercial hydrogen plant. Scaling thermochemical hydrogen from a demonstrator to industrially relevant volumes will take years of engineering, materials work on the corrosive chemistry involved, and cost reduction before it can rival electrolysis.

Even so, being first to demonstrate nuclear-heat-driven Cu-Cl hydrogen gives India an early position in a route to clean hydrogen that few countries are pursuing at this maturity — and adds a distinctly Indian, reactor-coupled option to the global search for carbon-free fuels.

Sources

• Department of Atomic Energy inaugurates world's first hydrogen production facility based on copper-chlorine cycle using nuclear heat from FBTR — ANI
• Department of Atomic Energy Inaugurates World's First Hydrogen Production Facility Based on Copper-chlorine Cycle — LatestLY
• India Commissions World's First Nuclear Heat-Based Hydrogen Production Facility Using Copper-Chlorine Cycle At Kalpakkam — Swarajya
• India advances clean energy push with world's first nuclear-powered hydrogen production facility — The Week
• India inaugurates world's first hydrogen production facility that uses nuclear reactor heat — Prokerala