PM Modi during the core loading of indigenous Prototype Fast Breeder Reactor, Kalpakkam

India stands at a critical juncture in its nuclear energy development with the Prototype Fast Breeder Reactor (PFBR) expected to achieve first criticality by March 2026 and plans to deploy five indigenous Small Modular Reactors (SMRs) by 2033.

These developments represent significant milestones in India's decades-old three-stage nuclear power program conceived by physicist Homi Bhabha. The PFBR's commissioning will mark India's entry into the second phase of this strategic program, positioning the country as only the second nation after Russia to operate a commercial fast breeder reactor. Simultaneously, the government has allocated ₹20,000 crore for SMR development, which is expected to contribute over 40 GW to India's ambitious target of achieving 100 GW of nuclear energy capacity by 2047. Despite facing significant delays in the PFBR project, India's commitment to nuclear expansion demonstrates its determination to leverage indigenous technology for energy security while utilising its abundant thorium reserves.

India's Three-Stage Nuclear Power Program

India's three-stage nuclear power program was formulated by Homi Bhabha in the 1950s as a strategic approach to achieve long-term energy independence using the country's nuclear resources. The program was specifically designed to work around India's limited uranium reserves, which constitute only about 1-2% of global reserves, while capitalising on its abundant thorium resources, estimated at approximately 25% of the world's known thorium reserves. This visionary approach addressed India's unique energy challenges through a carefully planned technological progression.

The ultimate focus of this three-stage program is on enabling India's thorium reserves to meet the country's energy requirements. Thorium itself is not a fissile material and cannot directly undergo fission to produce energy. Instead, it must be transmuted to uranium-233 in a reactor fuelled by other fissile materials, which necessitates the development of breeder reactor technology. The Indian nuclear establishment has estimated that the country could potentially produce 500 GWe for at least four centuries using just its economically extractable thorium reserves, highlighting the long-term strategic value of this approach.

The program's significance extends beyond energy security to demonstrate India's technological self-reliance and indigenous development capabilities in advanced nuclear technologies. This has been particularly important given the international isolation that India's nuclear program faced for several decades before the 2005 Indo-US Nuclear Deal and the NSG waiver opened new avenues for international collaboration.

Current Status And Implementation Challenges

Despite its strategic importance, India's three-stage nuclear program has faced significant implementation challenges and delays. The Prototype Fast Breeder Reactor, central to the second stage of the program, has experienced multiple postponements since construction began in 2004. Originally expected to be completed in September 2010, the PFBR is now anticipated to achieve first criticality by March 2026, representing a delay of nearly 16 years from the initial timeline.

These delays have had substantial cost implications, with the project's budget doubling from ₹3500 Crores ($422 million) to ₹7,700 Crores due to the extended timeline. Critics have pointed out that the reactor is taking more than twice the expected period to complete, raising questions about project management and technological challenges in implementing such advanced nuclear systems.

The repeated delays of the PFBR have affected the overall progression of India's nuclear program, particularly the transition to thorium utilisation in the third stage. Meanwhile, India continues to import thousands of tonnes of uranium from Russia, Kazakhstan, France, and Uzbekistan to fuel its existing fleet of nuclear reactors, which has somewhat alleviated immediate fuel supply concerns but increased dependency on international markets.

The Prototype Fast Breeder Reactor: Design And Technical Specifications

The Prototype Fast Breeder Reactor being constructed at Kalpakkam, Tamil Nadu, is a 500 MWe/1,250 MWth sodium-cooled fast breeder nuclear reactor designed to use plutonium-based mixed oxide fuel. This first-of-its-kind reactor for India was designed by the Indira Gandhi Centre for Atomic Research (IGCAR) based on decades of experience gained from operating the lower power Fast Breeder Test Reactor (FBTR).

As a fast breeder reactor, the PFBR is designed to produce more fuel than it consumes – a crucial characteristic for India's nuclear strategy that aims to maximise the utilisation of its limited uranium resources. The reactor uses liquid sodium as a coolant, which allows neutrons to maintain higher energies and facilitate the breeding process, converting non-fissile uranium-238 to plutonium-239 that can be used as fuel in subsequent cycles.

The design incorporates advanced safety features and has undergone extensive safety reviews by the Atomic Energy Regulatory Board (AERB). The core loading process has been implemented in a phased manner, beginning with the insertion of control sub-assemblies, followed by blanket sub-assemblies, with the final stage involving loading of fuel sub-assemblies into the reactor core.

Progress Towards Commissioning

Recent developments indicate significant progress in the PFBR project. India's Atomic Energy Regulatory Board has granted permission for the "first approach to criticality" for the reactor, marking a crucial regulatory milestone. The AERB approved this step following comprehensive assessments, extensive safety reviews, and plant visitations, responding to BHAVINI's application for first approach to criticality.

According to information provided to the Parliamentary Standing Committee on Science and Technology, the 500 MW PFBR is in an advanced stage of integrated commissioning, with expected first criticality by March 2026. The report doesn't share details on why it would take two years to operationalise the breeder reactor after loading the fuel and getting the regulatory nod, but the process typically involves several steps of testing and gradual power escalation before commercial operation.

Once criticality is achieved – meaning the establishment of a sustained nuclear chain reaction – it may take a few more months to connect the reactor to the commercial electricity grid. The successful operation of this prototype will pave the way for future fast breeder reactors in India and mark the country's entry into the second phase of its three-stage nuclear program.

Indigenous Development And Strategic Significance

A notable aspect of the PFBR project is its emphasis on indigenous development and self-reliance. The reactor has been fully designed and constructed indigenously by Bharatiya Nabhikiya Vidyut Nigam Limited (BHAVINI) with significant contributions from more than 200 Indian industries, including micro, small, and medium enterprises (MSMEs). This aligns with India's "Atmanirbhar Bharat" (self-reliant India) initiative.

Once commissioned, India will become only the second country after Russia to have a commercial operating Fast Breeder Reactor, highlighting the technological significance of this achievement. The successful demonstration of this technology will enhance India's standing in the global nuclear community and reduce dependence on foreign technology for future nuclear development.

The indigenous development of the PFBR has helped create a domestic supply chain for advanced nuclear components, generated high-skilled employment opportunities, and strengthened India's technological capabilities in the nuclear sector. These benefits extend beyond the immediate energy production to contribute to broader industrial and technological development goals.

Small Modular Reactors: India's Emerging Nuclear Avenue: India's ₹20,000 Crore SMR Program

In a significant expansion of its nuclear strategy, India has launched an ambitious Small Modular Reactor (SMR) program with a substantial allocation of ₹20,000 crore. As announced during the presentation of the Union Budget 2025, this program aims to develop at least five indigenously designed SMRs by 2033. Finance Minister Nirmala Sitharaman emphasised the importance of these reactors as part of India's broader Nuclear Energy Mission, which targets developing at least 100 gigawatts of nuclear energy by 2047.

The SMR program encompasses various reactor designs, including Bharat Small Modular Reactors, gas-cooled micro modular reactors, and 50 MWe SMRs. This diversity reflects India's strategy to develop different technologies suitable for various applications and deployment scenarios. The program's substantial funding demonstrates the government's commitment to diversifying its nuclear technology portfolio and accelerating the development of these more flexible, scalable nuclear options.

To facilitate this ambitious plan, the government intends to amend key legislation, including the Atomic Energy Act and the Civil Liability for Nuclear Damage Act, to enable greater participation from the private sector. Currently, nuclear energy production in India is largely controlled by government-run entities, but increased private sector involvement is seen as necessary to accelerate development and ensure steady growth in clean energy generation.

Strategic Applications And Deployment Scenarios

The Department of Atomic Energy has outlined three broad strategic applications for Small Modular Reactors in India's energy landscape. First, SMRs are envisioned for repurposing ageing thermal power plants, potentially offering a cleaner alternative while utilising existing infrastructure and grid connections. This approach could significantly reduce the carbon footprint of India's power sector while extending the useful life of existing power plant sites.

Second, SMRs are being developed for captive power generation aimed at energy-intensive domestic heavy industries such as steel and aluminium manufacturing. These industries require reliable, continuous power supply and contribute significantly to India's industrial emissions. Dedicated SMRs could provide them with stable, carbon-free electricity, enhancing both their competitiveness and environmental performance.

Third, smaller SMRs, typically around 50 MWe, are being designed for deployment in remote locations where extending the conventional power grid might be challenging or economically unfeasible. This application recognises India's geographic diversity and the challenges of providing reliable electricity to isolated or difficult-to-access regions. Small, autonomous nuclear plants could provide reliable baseload power to such areas, supporting rural development and energy access.

Contribution To India's 100 GW Nuclear Target

The SMR program forms a crucial component of India's ambitious target of achieving 100 gigawatts of energy from the nuclear sector by 2047, as announced in the Nuclear Energy Mission. According to the Department of Atomic Energy's plans, more than 40 GW of nuclear power will come from Small Modular Reactors, highlighting their central role in India's future energy mix.

This target represents a massive scale-up from India's current nuclear capacity and signals a strong commitment to nuclear energy as a key component of the country's clean energy transition. The focus on SMRs is particularly strategic because these reactors offer several advantages over conventional large nuclear plants. They are more flexible, can be manufactured in factories (reducing construction time and costs), require smaller initial capital investment, and can be deployed incrementally as needed.

The government's announcement of the Nuclear Energy Mission during the Union Budget 2025 presentation, along with specific targets and funding allocations, indicates the high priority assigned to nuclear energy in India's "Viksit Bharat" (Developed India) vision for 2047. The mission's ambitious goals, if achieved, would position India among the world's leading nuclear energy producers and significantly reduce the country's carbon emissions from the power sector.

Challenges And Future Prospects

The PFBR's lengthy timeline offers important lessons for India's nuclear ambitions. Originally expected to reach criticality in 2010, the reactor has faced multiple postponements, with the current target set for March 2026. These delays represent valuable learning experiences that could inform the approach to future projects, including the SMR program.

The causes of these delays have been multifaceted, including technical challenges inherent in developing first-of-a-kind technology, regulatory hurdles, supply chain issues, and project management complications. The experience underscores the complexity of developing advanced nuclear technologies and the importance of realistic planning and scheduling for future projects.

The cost implications have been substantial, with the PFBR's budget doubling from the initial estimate. This cost escalation highlights the financial risks associated with nuclear projects and the need for robust financial planning and contingency provisions. For the upcoming SMR program and broader nuclear expansion, improved project management practices, more realistic timelines, and better risk assessment could help avoid similar delays.

Policy And Technology Innovation

To support its ambitious nuclear plans, India is evolving its policy framework while pursuing technological innovation. The planned amendments to key legislation, including the Atomic Energy Act and the Civil Liability for Nuclear Damage Act, represent a significant shift from the traditional government monopoly in India's nuclear sector. These changes aim to create a more conducive environment for investment and accelerated development.

Technological innovation is evident in the diverse SMR designs being pursued, from gas-cooled micro reactors to larger 50 MWe units. This portfolio approach allows India to develop solutions tailored to different needs while spreading technological and market risks. The emphasis on indigenous development ensures that the technology will be adapted to India's specific conditions and requirements.

The success of these initiatives will depend on creating an effective ecosystem that combines regulatory oversight with innovation incentives, skilled workforce development, and supply chain strengthening. The experience gained from both the PFBR project and the upcoming SMR program will be crucial in refining India's approach to nuclear technology development and deployment.

Conclusion

India's nuclear plans, centred around the Fast Breeder Reactor targeted for 2026 and the development of five Small Modular Reactors by 2033, represent a comprehensive approach to addressing the country's long-term energy security while pursuing technological self-reliance. These initiatives are firmly rooted in Homi Bhabha's visionary three-stage nuclear program, which aims to leverage India's abundant thorium reserves.

Despite the challenges and delays faced by the PFBR project, the recent regulatory approvals and progress toward criticality indicate that India is steadily advancing toward the second stage of its nuclear program. Simultaneously, the ambitious SMR program, backed by substantial financial commitment, demonstrates India's determination to diversify its nuclear technology portfolio and accelerate capacity addition.

The target of achieving 100 GW of nuclear capacity by 2047, with more than 40 GW expected to come from SMRs, reflects the central role envisioned for nuclear energy in India's future energy mix. If successful, these initiatives would not only enhance India's energy security but also contribute significantly to its climate change mitigation efforts and industrial development goals, positioning the country as a major player in the global nuclear energy landscape.

IDN