BARC and IGCAR Demonstrate Triple-Function Fast Breeder Test Reactor
Scientists at the Bhabha Atomic Research Centre (BARC), Mumbai, and the Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam, have achieved a milestone by using the Fast Breeder Test Reactor (FBTR) to simultaneously generate electricity, convert non-fissile thorium into nuclear fuel, and produce green hydrogen from its waste heat. This innovation addresses multiple energy challenges in a single reactor system.
Hydrogen's Critical Role in Industry and Transport
Hydrogen is essential as a raw material for manufacturing ammonia, which is the starting point for urea fertilisers, and for producing methanol, a feedstock for plastics, paints, and industrial chemicals. It is also used in petroleum refineries for hydrodesulphurisation to remove sulphur from fuels. In future transport, fuel cells combine hydrogen with oxygen to generate electricity, with only water vapour as exhaust. Fuel-cell vehicles can be refuelled within minutes, making them suitable for heavy trucks, ships, and potentially aircraft, where battery-powered systems face weight and charging-time limitations.
Green Hydrogen Production Challenges
Hydrogen is not found free in nature; it must be extracted from water or hydrocarbons by breaking strong chemical bonds, which requires significant energy. Currently, most hydrogen is produced via steam methane reforming from natural gas or electrolysis. When the electricity for electrolysis comes from coal- or gas-fired power stations, the process results in substantial carbon emissions. Hydrogen from such fossil-fuel-dependent routes is termed grey hydrogen, shifting pollution from the point of use to the point of production. Consequently, countries are investing in green hydrogen with little or no carbon emissions. India has chosen a novel route leveraging its thorium reserves.
India's Thorium Advantage and Fast Breeder Technology
India possesses one of the world's largest thorium reserves but limited uranium reserves, with much of its uranium ore being low quality. Thorium cannot be used directly as nuclear fuel; it must first be converted into uranium-233 (U-233). Fast breeder reactors (FBRs) achieve this by placing a blanket of thorium around the reactor core. High-energy neutrons from the core are absorbed by the thorium, which undergoes nuclear transformations to become U-233, an excellent reactor fuel. Because these reactors produce fresh fuel while generating electricity, they are called breeder reactors.
Developing this technology was challenging due to technology denial regimes imposed by western countries. Indian scientists had to develop fast breeder reactor technology largely independently. IGCAR commissioned the FBTR in 1985 to gain experience in designing, constructing, and operating sodium-cooled fast reactors. Four decades of operating experience laid the foundation for the 500-megawatt prototype fast breeder reactor (PFBR), which achieved first criticality in 2026.
Utilising Waste Heat for Hydrogen Production
A nuclear reactor converts only about one-third of its thermal energy into electricity; the remaining two-thirds is released as waste heat. Engineers have sought ways to use this heat productively. One established application is district heating in countries with severe winters, such as Russia, China, and several European nations. Another is desalination; at Kalpakkam, a desalination plant coupled to the Madras Atomic Power Station uses a hybrid multi-stage flash and reverse osmosis system to produce drinking water from seawater.
The next frontier is hydrogen production. Two broad approaches are being explored: improving electrolysis efficiency by using reactor heat to generate steam, reducing electricity consumption, and thermochemical cycles where heat drives chemical reactions to split water. Reactor temperature is critical—conventional pressurised water reactors operate at about 300-330°C, while most thermochemical cycles require higher temperatures. China is investigating the sulfur-iodine cycle using its high-temperature reactor at Shidao Bay, with helium coolant at around 750°C.
India has taken a different approach. The sodium coolant in the FBTR leaves the reactor at about 480-520°C. Scientists at BARC developed the copper-chlorine (Cu-Cl) thermochemical cycle to operate efficiently within this temperature range. Working with engineers at IGCAR, they integrated the process into the reactor and demonstrated that waste heat can produce green hydrogen. The FBTR has thus shown that a single reactor can generate electricity, breed nuclear fuel, and produce green hydrogen.
Next Steps: Scaling Up to Commercial Plants
The hydrogen plant attached to the FBTR is a technology demonstrator. The next challenge is to scale up and develop commercial thermochemical hydrogen plants that can utilise waste heat from future fast breeder reactors. According to TV Venkateswaran, the demonstration marks a significant step toward broadening the role of nuclear energy beyond power generation.
