India’s Prototype Fast Breeder Reactor at Kalpakkam achieved first criticality on 6 April, marking not just the activation of a reactor but the culmination of seven decades of scientific perseverance, strategic foresight, and decisive political will.
This milestone belongs foremost to India’s nuclear scientists and engineers, who carried the mission through years of sanctions, scepticism, and inadequate political support.
Yet it also compels reflection on why the journey took so long, what the achievement truly signifies, and what must now follow.
The foundations of India’s nuclear program were laid by Dr Homi Jehangir Bhabha, one of the country’s finest scientific minds. As early as 1954, Bhabha articulated a three-stage nuclear power programme tailored to India’s resource profile: abundant thorium, modest uranium, and the imperative of long-term energy self-reliance. The first stage involved Pressurised Heavy Water Reactors fuelled by natural uranium, producing electricity while generating plutonium.
The second stage, now realised at Kalpakkam, deploys Fast Breeder Reactors that consume plutonium while breeding more fissile material and converting thorium into uranium-233. The third stage will see Advanced Heavy Water Reactors running on the thorium–uranium-233 cycle, unlocking India’s vast thorium reserves estimated at over three lakh tonnes.
This is not merely an energy programme but a civilizational insurance policy designed to free India from perpetual dependence on imported fuels and foreign technology.
Criticality represents the moment a reactor sustains a controlled, self-sustaining nuclear chain reaction. For a Fast Breeder Reactor, this is especially significant. Unlike conventional reactors, the PFBR uses fast neutrons and liquid sodium coolant, operating at the frontier of nuclear engineering.
India now joins an exclusive club, becoming only the second country after Russia to operate a commercial fast breeder reactor at this scale. Once the envisaged fleet of Fast Breeder Reactors is operational, India will produce more fissile fuel than it consumes, creating a self-amplifying cycle of energy sovereignty.
The political environment has been pivotal in accelerating progress. Prime Minister Narendra Modi has treated nuclear energy as a national priority rather than a bureaucratic inheritance. His presence at Kalpakkam in March 2024 during core loading was a signal of political commitment.
The Nuclear Energy Mission announced in the Union Budget 2025–26 set a target of 100 GW of nuclear capacity by 2047, backed by funding and the SHANTI Act, 2025, which modernised India’s nuclear legal framework. Modi declared that the PFBR reflects both scientific capability and engineering strength, underlining the depth of political resolve behind the mission.
Equally transformative is the decision to open India’s nuclear sector to private participation. For decades, nuclear power was the exclusive preserve of the state, constrained by regulatory inertia and risk aversion.
Allowing private and joint-venture investment marks a structural rupture, bringing financing, competition, project discipline, and faster deployment. For a country needing tens of gigawatts of firm, zero-carbon power, this reform is a necessity.
The delays at Kalpakkam must also be acknowledged. Construction began in 2004 with a target of 2010, but criticality was achieved only in 2026.
The Civil Liability for Nuclear Damage Act of 2010 imposed supplier liability provisions outside international norms, deterring global vendors and paralysing the Indo-US civil nuclear deal. Budgetary allocations were anaemic, and the three-stage programme was treated as rhetoric rather than priority. Scientists persevered through neglect, but the nation lost valuable time.
The contrast after 2014 is stark. The Modi government brought political will, institutional reform, and sustained investment. Ten reactors were approved in bulk, streamlining processes.
The ASHVINI joint venture between NPCIL and NTPC was structured to build four 700 MW reactors in Rajasthan, marking the first major inter-PSU collaboration. Bilateral agreements diversified uranium supply, ending chronic shortages that had forced reactors to run at 40% capacity.
Nuclear electricity generation rose from 34,000 million units in 2013–14 to nearly 57,000 million units in 2024–25, a 67% increase. Installed capacity grew from 4,780 MW in 2014 to 8,180 MW in 2024, a rise of over 70%.
The SHANTI Act overhauled legal frameworks, while duty exemptions on equipment imports were extended until 2035. Budget 2025–26 committed ₹20,000 crore for Small Modular Reactor R&D, alongside a roadmap to nearly triple capacity to 22,480 MW by 2031–32.
India now stands at the threshold of the third stage envisaged by Bhabha. Thorium-based reactors promise independence from imported nuclear fuel, with reserves sufficient to power the country for centuries.
Nuclear energy currently contributes about 3% of India’s electricity. With the 100 GW target, this share could rise to 15–20% by mid-century, providing firm base-load power that intermittent renewables cannot. In a world demanding deep decarbonisation without sacrificing development, nuclear energy is indispensable.
Kalpakkam is not the finish line but the opening of a door built by generations of Indian scientists. Under Modi’s leadership, India has shown intent and capacity to translate vision into reality through missions, reforms, and empowerment of its scientific establishment. The atom has long been India’s servant in waiting. Kalpakkam signals that the wait is finally over.
IDN (With Agency Inputs)
