India’s nuclear power programme has reached a defining milestone with the 500 MWe prototype fast breeder reactor at Kalpakkam, Tamil Nadu, achieving first criticality.

This marks the beginning of a controlled and sustained nuclear fission chain reaction, a crucial step in India’s three-stage nuclear strategy. Developed by Bharatiya Nabhikiya Vidyut Nigam Limited, the PFBR represents India’s entry into the second stage of its long-term plan to harness natural uranium, plutonium and thorium-derived uranium-233 for sustainable and self-reliant nuclear power generation.

Fast breeder reactors are designed to generate more fissile material than they consume, effectively multiplying fuel during operation. This unique capability enhances resource efficiency, enabling India to extract far greater energy from its limited uranium reserves.

By reducing dependence on imports and supporting a gradual transition to abundant domestic thorium resources, FBRs provide India with a strategic advantage in energy security. Upon full commissioning, India will become only the second country after Russia to operate a commercial fast breeder reactor, underscoring its technological maturity and indigenous capability.

India’s installed nuclear power capacity currently stands at 8.78 GW. During 2024-25, nuclear power plants generated 56,681 MUs of electricity, contributing about 3.1 per cent of total electricity generation.

Five pressurised heavy water reactors aggregating 3,500 MW are under construction, while eight more totalling 5,600 MW are in the pre-project stage. In addition, four pressurised water reactors with a combined capacity of 4,000 MW are under implementation. These projects are expected to be commissioned in phases by 2031-32, raising total capacity to nearly 22 GW.

On the back-end, two integrated nuclear recycle facilities are under development. The Integrated Nuclear Recycle Plant in Tarapur and the Fast Reactor Fuel Cycle Facility in Kalpakkam will support reprocessing, waste management and fuel fabrication for spent fuels from PHWRs and FBRs. 

Meanwhile, the Nuclear Fuel Complex in Kota, Rajasthan, is in the final stages of commissioning and will produce 500 tonnes per year of fuel bundles for 700 MWe PHWRs, further strengthening the supply chain.

The government has outlined an ambitious roadmap through the Nuclear Energy Mission announced in the Union Budget 2025-26, targeting 100 GW of nuclear power capacity by 2047. Achieving this will require investments of at least ₹20 Lakh Crores, based on a baseline cost of ₹22 Crores per MW. 

The Bhabha Atomic Research Centre is spearheading advanced reactor technologies, including the 200 MWe Bharat Small Modular Reactor, the 55 MWe SMR-55, and a high-temperature gas-cooled reactor for hydrogen production. ₹20 Crores has been allocated for SMR development, with a target to operationalise at least five indigenously designed SMRs by 2033.

To support expansion, the government enacted the SHANTI Act, 2025, modernising the legal framework for nuclear energy and permitting limited private sector participation under regulatory oversight. India has also signed intergovernmental agreements with 18 countries on civil nuclear cooperation for peaceful purposes.

The Atomic Energy Commission has approved a foreign direct investment policy in nuclear power, currently under consultation, and has highlighted the benefits of adopting a fleet-mode approach to accelerate approvals and streamline construction timelines.

Fast breeder technology is a critical link between the current PHWR fleet and future thorium-based reactors. PFBRs incorporate advanced safety features, liquid sodium coolant technology and a closed fuel cycle, ensuring efficient fuel utilisation, improved safety and reduced nuclear waste.

The Kalpakkam project reflects India’s indigenous capabilities in reactor design, engineering and manufacturing, with contributions from numerous domestic institutions, scientists, engineers and industry partners. The fast breeder programme is expected to strengthen expertise in nuclear fuel cycle technologies, advanced materials and reactor physics, supporting future reactor development.

As India expands its clean energy portfolio, nuclear power will provide reliable, low-carbon base-load generation. The PFBR milestone not only strengthens long-term energy security but also aligns with the national objective of building a self-reliant and sustainable energy system.

By leveraging the advantages of fast breeder reactors, India is positioning itself to maximise resource efficiency, reduce import dependence, and transition towards thorium utilisation, ensuring a resilient and forward-looking nuclear future.

IDN (With Agency Inputs)