India has ambitious plans to expand nuclear energy. The country is seeking to increase its conventional nuclear power capacity rapidly to meet soaring electricity demand. At the same time, researchers at a laboratory in Gujarat are working on a very different technology: nuclear fusion.
In September 2026, scientists at the Institute for Plasma Research (IPR) commissioned a high-power microwave system on its experimental machine, the Steady State Superconducting Tokamak-1 (SST-1). The device, called a gyrotron, operates at 82.6 gigahertz (GHz) and can deliver up to 400 kilowatts (kW) of power.
This is an important development in fusion research, but it is not the beginning of a clean-energy revolution. The gyrotron is a laboratory instrument designed to heat plasma and help researchers understand and control it. It will not generate electricity for homes.
Here is a closer look at India’s nuclear programme, its expansion plans and the challenges of making fusion a practical source of energy.
A timeline of India’s civil nuclear programme:
1944–45: Homi Jehangir Bhabha proposes a centre for fundamental nuclear research. The Tata Institute of Fundamental Research is established in 1945.
1948: The Atomic Energy Act establishes the legal framework for state control of atomic energy. The Atomic Energy Commission is set up the same year.
1954: The Department of Atomic Energy (DAE) is established in August.
1956: Apsara, India’s first nuclear research reactor, goes critical on August 4.
1969: Tarapur Atomic Power Station in Maharashtra, with two 160 MW reactors supplied by the US, begins commercial operation on October 28, marking the start of nuclear electricity generation in India.
1972–73: Rajasthan Atomic Power Station Unit 1, India’s first pressurised heavy water reactor, begins operation. Commercial operation follows in 1973 after initial technical problems.
1984: The Madras Atomic Power Station at Kalpakkam begins operation.
1990s: Kakrapar in Gujarat and Kaiga in Karnataka strengthen India’s indigenous pressurised heavy water reactor programme. Additional units are commissioned at existing stations.
1988–2002: India and the Soviet Union, later Russia, reach agreements on the Kudankulam nuclear power project in Tamil Nadu. The project is revived in the late 1990s, and construction begins in the early 2000s.
2004: Construction begins on the 500 MW Prototype Fast Breeder Reactor (PFBR) at Kalpakkam.
2005–08: India and the US conclude a civil nuclear agreement, paving the way for renewed international nuclear commerce under safeguards.
2014 and 2017: Kudankulam Units 1 and 2, Russian-designed 1,000 MW reactors, enter commercial operation in December 2014 and March 2017, respectively.
2017: The government approves ten indigenous 700 MW pressurised heavy water reactors, marking a step up from the earlier 540 MW design.
2020–24: Kakrapar Unit 3, India’s first 700 MW reactor of this design, goes critical in 2020 and enters commercial operation on June 30, 2023: Unit 4 follows on March 31, 2024.
2025: Rajasthan Atomic Power Station Unit 7, another 700 MW reactor, begins commercial operation on April 15.
2026: The 500 MW Prototype Fast Breeder Reactor at Kalpakkam achieves first criticality on April 6, marking a major milestone in the second stage of India’s three-stage nuclear programme.
2026: India’s installed nuclear power capacity stands at 8.78 GW across 24 reactors. Further reactors are under construction or in the commissioning process.
2047: The Nuclear Energy Mission targets 100 GW of nuclear capacity. The government envisages about 22 GW by 2031–32, with NPCIL expected to account for 54 GW by 2047 and the remaining capacity to come from other public-sector entities, private companies and joint ventures.
What is the difference between nuclear fission and fusion?
Fission splits heavy atomic nuclei, while fusion combines lighter nuclei to form heavier ones. Both processes release energy, but they work in fundamentally different ways.
India’s existing nuclear power plants rely on fission. Neutrons strike the nuclei of heavy atoms, usually uranium, causing them to split. This releases energy and additional neutrons, which can trigger further fission reactions. A controlled chain reaction produces heat, which is used to generate steam and drive turbines.
Fusion works in the opposite way. Under suitable conditions, light atomic nuclei combine to form heavier nuclei, releasing energy. A leading approach uses two hydrogen isotopes, deuterium and tritium, which fuse to form helium and a neutron.
The challenge is to make the nuclei overcome their mutual electrical repulsion. This requires temperatures of more than 100 million degrees Celsius in a typical magnetic-confinement fusion experiment — several times hotter than the Sun’s core.
What is plasma, and why is it so difficult to control?
At these extreme temperatures, the fuel becomes plasma, an electrically charged state of matter in which electrons separate from atomic nuclei.
Controlling plasma is one of the central challenges of fusion research. The plasma must be confined and kept hot and dense enough for fusion reactions to occur. In a tokamak, powerful magnetic fields hold the plasma away from the vessel walls.
If the plasma touches the walls, it cools rapidly and can damage the surrounding materials. Instabilities can also disrupt confinement, making it difficult to sustain the conditions required for fusion.
What does the new gyrotron heater do?
The Institute for Plasma Research operates experimental tokamaks, including SST-1 and ADITYA-U, to study plasma behaviour and develop fusion-related technologies.
A gyrotron generates high-frequency electromagnetic waves that transfer energy to electrons in the plasma. This technique, known as electron cyclotron resonance heating (ECRH), allows researchers to heat the plasma and influence its behaviour.
The new 82.6 GHz system on SST-1 can deliver up to 400 kW of radio-frequency power in pulses lasting up to 0.5 seconds. It adds to the institute’s existing heating capabilities and helps researchers investigate plasma heating and control under different operating conditions.
The achievement is a step forward in fusion research, not a demonstration of a working fusion power plant. Major challenges remain, including sustaining stable plasma for longer periods, achieving useful fusion output and developing materials that can withstand the extreme conditions inside a future reactor.
Does this experiment contribute to India’s electricity supply?
No. The experiment is part of fusion research; India’s operating nuclear power plants generate electricity through fission.
As of July 2026, India had an installed nuclear power capacity of 8.78 GW across 24 reactors. Nuclear power accounted for about 3.1% of the country’s total electricity generation in 2025–26. Additional fission reactors are being built or commissioned to increase that share.
The distinction matters: a research milestone in fusion does not add generating capacity to the electricity grid.
If fusion cannot yet generate commercial electricity, why invest in it?
Fusion is a long-term research endeavour, not an immediate solution to India’s electricity needs. If it can eventually be harnessed commercially, it could provide a low-carbon source of energy, but significant scientific and engineering obstacles remain.
India has participated in the international ITER fusion project in France since 2005. Its domestic research programme helps train scientists and engineers, develop specialised technologies and build expertise that could contribute to future fusion experiments.
The new gyrotron strengthens this research infrastructure. It is a useful step towards better control of plasma, but it does not establish that commercially viable fusion power is close at hand.
What is India’s nuclear expansion plan, and what are the main hurdles?
The Nuclear Energy Mission, announced in the Union Budget for 2025–26, sets a target of 100 GW of nuclear capacity by 2047. Starting from 8.78 GW in 2026, India would need to add more than 90 GW over roughly two decades.
The government envisages increasing capacity to around 22 GW by 2031–32. By 2047, the Nuclear Power Corporation of India Limited (NPCIL) is expected to account for 54 GW, with the remaining 46 GW envisaged from other public-sector entities, private companies and joint ventures.
Financing is a major challenge. Nuclear plants require substantial upfront investment, long construction periods and extensive safety and regulatory clearances. Delays can raise costs and postpone the point at which projects begin generating revenue. Private-sector participation will also depend on a workable legal and commercial framework.
Another important distinction is between installed capacity and electricity generation. Capacity measures a plant’s maximum rated output; generation measures the electricity it actually produces over time. Reactors require maintenance and refuelling, and their output varies with operating conditions.
For example, a fleet with 100 GW of installed capacity operating at an average capacity factor of 85% would generate about 745 terawatt-hours (TWh) of electricity annually. This is an illustration of the difference between capacity and output, not a forecast of India’s future generation.
How does India’s 100 GW target compare with other countries’ nuclear capacity?
The International Atomic Energy Agency’s Power Reactor Information System (PRIS) tracks operating nuclear reactors and their net electrical capacity. Its published figures put the United States at about 97 GW, France at 63 GW and China at nearly 59 GW of operating nuclear capacity. Russia has about 28 GW, South Korea 25.6 GW, Ukraine 13.1 GW, Canada 12.7 GW and Japan 12.6 GW.
India’s installed capacity is substantially lower, although reported totals can vary with the date and the reactors included in each dataset. Reaching 100 GW would put India among the world’s largest nuclear power producers by installed capacity, at a level comparable to the US fleet today.
That comparison illustrates the scale of the ambition. It should not be read as a prediction that India will match the US in actual electricity generation, which also depends on reactor performance, capacity factors and the timing of new projects.
Why is India pursuing nuclear expansion so aggressively?
India’s strategy rests on three broad objectives: energy security, international cooperation and the development of indigenous technology.
First, nuclear power could diversify the electricity mix and help meet rising demand while supporting India’s longer-term goal of net-zero emissions by 2070. Its contribution to reducing fossil-fuel use will depend on how quickly capacity is built and how it fits into the wider energy system.
Second, international partnerships remain important. Russia is building additional reactor units at Kudankulam, while India is pursuing civil nuclear cooperation with other countries. In March 2026, Canada’s Cameco signed an agreement to supply uranium to India, strengthening the focus on fuel security.
Third, the government wants to develop domestic nuclear technologies, including small modular reactors (SMRs). It has set an ambition to have at least five indigenous SMRs operational by 2033. These reactors, generally designed to produce up to 300 MW each, could offer more flexible deployment options for industrial users and other sites requiring reliable power.
However, smaller size does not automatically make a reactor cheaper or easier to build. Costs, licensing, construction schedules, safety and the availability of a reliable supply chain will determine whether the technology can be deployed at scale.
The Prototype Fast Breeder Reactor at Kalpakkam is another important part of India’s long-term strategy. It achieved first criticality on April 6, 2026, marking progress towards the second stage of the country’s three-stage nuclear programme.
A fast breeder reactor is designed to produce more fissile material than it consumes. The PFBR uses mixed uranium-plutonium oxide fuel and a uranium-238 blanket to breed plutonium-239. Over time, the programme is intended to support the use of India’s substantial thorium resources, which would require further technological development.
The path is long and technically demanding. France shut down its Superphénix fast breeder reactor in 1997, while Japan’s Monju reactor was decommissioned after years of technical problems and a major sodium leak. Their experiences underline the engineering, operational and economic challenges involved.
What did early predictions about nuclear energy get wrong?
India’s nuclear programme developed around a long-term strategy of building domestic expertise in fission before progressing to more advanced technologies. The Department of Atomic Energy was established in 1954, and Apsara, a 1 MW research reactor, achieved criticality on August 4, 1956. It was the first research reactor in Asia outside the Soviet Union.
The early optimism surrounding nuclear energy was not confined to India. On September 16, 1954, US Atomic Energy Commission chairman Lewis Strauss told a gathering of science writers in New York that electricity would become “too cheap to meter”. That prediction did not come to pass: nuclear power remained capital-intensive, and electricity bills did not disappear.
Fusion inspired similarly ambitious forecasts. At the 1955 International Conference on the Peaceful Uses of Atomic Energy in Geneva, Homi Bhabha predicted that controlled fusion could be achieved within about two decades. More than seven decades later, fusion research continues, with commercial power generation still an unfulfilled goal.
By 1958, physicist Edward Teller was taking a more cautious view, comparing the state of fusion research with aviation a century earlier and questioning whether fusion would become economically viable before the end of the 20th century.
The lesson is not that nuclear research has failed. Fission has become an established source of electricity, while fusion remains a difficult scientific and engineering challenge. India’s current expansion plans depend on technologies that already work; its fusion programme is an investment in what may become possible in the future.
