New Chapter in India's Nuclear Journey

Mains: GS - III – Science & Technology

Why in News?

India has marked a major milestone in its nuclear energy programme marking the initiation of a sustained nuclear chain reaction with its Prototype Fast Breeder Reactor (PFBR) at Kalpakkam in Tamil Nadu.

What about the Prototype Fast Breeder Reactor (PFBR)?

Fast Breeder Reactor (FBR) – It is a nuclear reactor that generates more fissile material (fuel) than it consumes by using fast neutrons to convert non-fissile materials like Uranium-238 into Plutonium-239.
These reactors are designed for high fuel efficiency, enabling the utilization of over 60 times more energy from natural uranium, and are critical for India's 3-stage nuclear program.
PFBR – It represents decades of indigenous research, design, and engineering.
Technology development – Indira Gandhi Centre for Atomic Research (IGCAR), an R&D centre under the Department of Atomic Energy.
Fuel & Design – Unlike conventional thermal reactors, the PFBR uses Uranium-Plutonium Mixed Oxide (MOX) fuel.
The fissile material used is recovered from the reprocessing of spent fuel from Pressurised Heavy Water Reactors, closing the loop on Stage 1.
Breeds More Than It Burns – The core of the PFBR is surrounded by a blanket of Uranium-238.
Fast neutrons convert this fertile material into fissile Plutonium-239, enabling the reactor to produce more fuel than it consumes.
Bridge to Stage 3 – The reactor is designed to eventually use Thorium-232 in the blanket.
Through transmutation, Thorium-232 will be converted into Uranium-233, the fuel that will power India's third stage of nuclear energy based on thorium.
Closed Fuel Cycle – The spent fuel generated by the PFBR will be reprocessed and recycled back into the reactor.
This closes the second-stage fuel cycle and paves the way for large-scale use of India's abundant thorium reserves in Stage 3.
Recent Achievement
Attained Criticality – The indigenously designed & built Prototype Fast Breeder Reactor (PFBR) at Kalpakkam in Tamil Nadu successfully attained its first criticality.
PFBR at Kalpakkam – It is a 500 MWe (MegaWatt electrical) reactor built by Bharatiya Nabhikiya Vidyut Nigam Limited (BHAVINI) at the Kalpakkam Nuclear Complex.
Significance – With this achievement, India has officially entered the second stage of its three-stage nuclear power programme, a vision first conceived by Dr. Homi Jehangir Bhabha, the architect of India's nuclear programme.
Once fully operational, India will become only the second country in the world after Russia to operate a commercial fast breeder reactor.

What is Criticality?

Criticality – It is the point at which a sustained and controlled nuclear fission chain reaction begins.
At this stage, neutrons produced by fission equal those lost through absorption and leakage, resulting in a stable power output.
It marks the transition from the construction phase to the operational phase and is the essential first step towards generating heat and, ultimately, electricity.

What about India's Three-Stage Nuclear Power Programme?

Goal – To progressively multiply domestic fissile resources and secure long-term energy independence.
Reserve status – India holds limited uranium reserves but one of the largest thorium reserves in the world.
3 stage Nuclear Programme
Stage 1: Pressurised Heavy Water Reactors (PHWRs)
- Natural uranium is used as fuel in PHWRs to generate power.
- The spent fuel from these reactors produces plutonium, which becomes the primary input for the next stage.
Stage 2: Fast Breeder Reactors (FBRs)
- The plutonium obtained from Stage 1 is used as fuel in Fast Breeder Reactors, which generate more fuel than they consume.
- The PFBR at Kalpakkam marks India's entry into this stage.
- These reactors will be used to breed Uranium-233 from thorium, laying the groundwork for Stage 3.
Stage 3: Thorium-Based Reactors
- This stage will harness India's vast thorium reserves at scale, using the Uranium-233 bred in Stage 2 as fuel.
- Thorium is considered a practically vast energy source and this stage holds the key to India's long-term energy security.
Each stage feeds into the next, making India's nuclear programme one of the most forward-looking energy strategies in the world.

What about India’s Current Nuclear Power Landscape?

Electricity mix – India's nuclear energy programme has maintained a steady presence in the country's electricity mix, now stands at a pivotal moment, with significant expansion planned over the coming years.
Installed Capacity – India's current nuclear capacity is 8.78 Gigawatt (GW).
In 2024–25, nuclear power plants generated 56,681 Million Units of electricity across the country.
Stable Contribution – Nuclear power has consistently accounted for around 3% of India's total electricity generation, in 2024–25, its share stood at 3.1%.
Planned Expansion – India's nuclear capacity is set to grow nearly 3x in the coming years.
With indigenous 700-Megawatt (MW) reactors and 1,000 MW reactors being developed through international cooperation, the installed capacity is projected to reach 22.38 GW by 2031–32.
International Cooperation – India has signed Inter-Governmental Agreements (IGAs) on Civil Nuclear Cooperation for peaceful purposes with 18 countries, reflecting the growing global confidence in India's nuclear programme.
Taken together, Nuclear energy is no longer just a supplementary source of power in India, it is fast becoming a cornerstone of the country's clean energy future.

What is India’s Long-Term Mission?

Nuclear Energy Mission – Announced in the Union Budget 2025–26, with the aim of achieving 100 GW of nuclear power generation capacity by 2047.
It also supports India's broader goal of achieving net zero carbon emissions by 2070.
India’s need for Nuclear Power
- Demand – India's energy demands are growing rapidly and its clean energy commitments are firm.
- Base-load reliability – Nuclear power is a base load source of electricity available round the clock, with lifecycle emissions comparable to renewables such as hydro and wind.
- Industrial backbone – It is uniquely placed to meet the always-on power needs of data centres, advanced industries, and emerging technologies.
- Energy security – Scaling nuclear capacity is therefore not just a strategic choice but a practical necessity for India's long-term energy security and clean power transition.

What are the measures taken by the government to drive India’s nuclear vision forward?

Financial Commitment – The Nuclear Energy Mission allocates Rs.20,000 crore towards the design, development, and deployment of Small Modular Reactors (SMRs), signaling a serious long-term investment in indigenous nuclear technology.
SMR Target – At least five indigenously designed SMRs are to be operational by 2033, strengthening India's clean and reliable energy roadmap.
BARC Initiatives – The Bhabha Atomic Research Centre (BARC) is leading the development of next-generation reactor designs, including
- The 200 mwe Bharat Small Modular Reactor (BSMR-200),
- The 55 mwe SMR-55, and
- A High-Temperature Gas-Cooled Reactor of up to 5 mwth (Megawatt thermal) designed for hydrogen generation.
SHANTI Act, 2025 – The Government has enacted the ‘The Sustainable Harnessing and Advancement of Nuclear Energy for Transforming India (SHANTI) Act, 2025, which consolidates and modernises India's nuclear legal framework.
It enables limited private participation in the nuclear sector under regulatory oversight, opening new avenues for collaboration and investment.
India’s nuclear future – India's long-term nuclear vision is ambitious by design.
With policy backing, dedicated funding, and indigenous research at its core, the country is building a nuclear future that is both self-reliant and globally significant.

What lies ahead?

The attainment of criticality at the Prototype Fast Breeder Reactor marks more than a technological milestone.
It reflects the maturity of India’s long standing nuclear vision and the strength of its indigenous capabilities.
From limited uranium resources to a future powered by thorium, India’s three stage programme is now moving steadily from design to delivery.
This moment therefore stands as both an achievement and a turning point, strengthening the country’s pathway towards energy security, technological self-reliance, and its net zero commitment for 2070.

Reference

PIB | A New Chapter in India's Nuclear Journey