Kalpakkam Prototype Fast Breeder Reactor
India's 500 MWe Prototype Fast Breeder Reactor (PFBR) at Kalpakkam, Tamil Nadu, achieved first criticality on 6 April 2026, marking a major milestone in India's indigenous nuclear programme and the transition toward the second stage of the country's three-stage nuclear power programme. The story traces back to Dr. Homi J. Bhabha, who formulated India's three-stage nuclear power programme in the 1950s around India's limited uranium resources and abundant thorium reserves. Decades of work by the Department of Atomic Energy, BARC, IGCAR and BHAVINI culminated in the indigenous design, construction and commissioning of the PFBR. The sodium-cooled fast breeder reactor is designed to generate 500 MWe while breeding additional fissile material from Uranium-238 and creating a pathway toward eventual utilisation of India's large thorium resources.
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Timeline
3 August 1948
Atomic Energy Commission established
India established the Atomic Energy Commission under the leadership of Dr. Homi J. Bhabha, laying the institutional foundation for the country's long-term nuclear programme.
3 August 1954
Department of Atomic Energy established
The Department of Atomic Energy was established directly under the Prime Minister, with Homi J. Bhabha as its first Secretary, creating the institutional structure that would drive India's indigenous nuclear programme.
1 January 1954
India's three-stage nuclear power programme conceived
Homi J. Bhabha formulated India's three-stage nuclear power programme around the country's limited uranium resources and large thorium reserves. The strategy envisioned using pressurised heavy water reactors first, fast breeder reactors second, and thorium-based systems in the third stage.
4 August 1956
APSARA becomes India's first nuclear reactor
India achieved first criticality of APSARA at Trombay, becoming the first Asian country outside the Soviet Union to operate a nuclear reactor. The reactor was developed under the leadership of Homi J. Bhabha and established India's early nuclear research capability.
1 January 1957
Atomic Energy Establishment Trombay begins development
The Atomic Energy Establishment Trombay became the centre of India's nuclear research and development activities under Bhabha's leadership. It was later renamed the Bhabha Atomic Research Centre in his honour.
24 January 1966
Homi J. Bhabha dies
Homi J. Bhabha died in an aircraft crash in 1966. His institutional foundations and three-stage nuclear strategy continued to guide India's nuclear programme for decades after his death.
1 January 1971
IGCAR established at Kalpakkam
The Indira Gandhi Centre for Atomic Research was established at Kalpakkam to develop advanced nuclear technologies, including fast breeder reactors, nuclear fuel, materials and associated fuel-cycle technologies.
18 October 1985
Fast Breeder Test Reactor achieves first criticality
The Fast Breeder Test Reactor at Kalpakkam achieved first criticality, providing India with a long-running experimental platform for fast-reactor fuels, materials, sodium technology and reactor systems.
1 January 2003
BHAVINI established
The Government of India established Bharatiya Nabhikiya Vidyut Nigam Limited to construct and operate India's commercial fast breeder reactors, creating the organisation responsible for the PFBR project.
1 October 2004
PFBR construction begins at Kalpakkam
Construction of the 500 MWe Prototype Fast Breeder Reactor began at Kalpakkam, based on fast-reactor technology developed indigenously by IGCAR.
24 September 2014
PFBR construction nears completion
The Department of Atomic Energy reported that construction of the 500 MWe PFBR was nearing completion, with major permanent in-core components installed.
1 January 2015
PFBR enters advanced commissioning phase
The reactor moved through final construction, system commissioning and safety-related testing as India prepared its first indigenous commercial-scale fast breeder reactor for operation.
4 March 2024
PFBR begins core loading
Prime Minister Narendra Modi witnessed the commencement of core loading at India's first indigenous 500 MWe Prototype Fast Breeder Reactor at Kalpakkam, marking a major step toward first criticality.
4 March 2024
More than 200 Indian industries contribute to PFBR
BHAVINI reported that the PFBR was indigenously designed and constructed with contributions from more than 200 Indian industries, including MSMEs, demonstrating the depth of India's domestic nuclear engineering and manufacturing ecosystem.
1 January 2025
PFBR progresses toward first criticality
Following core loading and regulatory clearances, BHAVINI continued integrated commissioning and preparation for the reactor's first approach to criticality.
6 April 2026
PFBR achieves first criticality
The 500 MWe Prototype Fast Breeder Reactor at Kalpakkam successfully achieved first criticality at 8:25 PM on 6 April 2026, initiating a controlled nuclear fission chain reaction for the first time.
6 April 2026
India advances into the second stage of its three-stage nuclear programme
The achievement of first criticality marked a major step in India's three-stage nuclear programme, with fast breeder technology serving as the bridge between the existing pressurised heavy water reactor fleet and the future utilisation of India's thorium resources.
6 April 2026
Decades of indigenous nuclear engineering culminate at Kalpakkam
The PFBR milestone represented decades of Indian research and engineering spanning nuclear physics, reactor design, fast-reactor technology, nuclear fuels, materials, sodium systems and large-scale domestic manufacturing.