NEW DELHI: India took a major step towards nuclear fuel self-reliance when its indigenously developed Prototype Fast Breeder Reactor (PFBR) at Kalpakkam in Tamil Nadu attained criticality on 6 April. This is the stage when a nuclear chain reaction can sustain itself.

This will enable India to leverage its vast reserves of thorium and reduce dependence on uranium imports. Once the reactor is fully operational, India will become the second country after Russia to have a commercial fast breeder reactor.

Mint looks at the significance of the development as India aims to achieve 100GW of installed nuclear power capacity by 2047.

What is a fast breeder reactor?

A fast breeder reactor is one that produces more fuel than it consumes while generating power. India’s fast breeder reactor was designed and developed by the Indira Gandhi Centre for Atomic Research, the R&D centre of the Department of Atomic Energy. It has a 500-megawatt electrical (MWe) capacity. Unlike conventional thermal reactors, these reactors use uranium, plutonium and thorium as fuel at various stages to generate electricity.

Why is the development significant for India?

Firstly, the technology was indigenously developed after decades of research, design and engineering. Secondly, once fully operational, India will become the second country after Russia to operate a commercial fast breeder reactor. The US, France, the UK, Japan and China have worked on the technology but have not succeeded so far.

Under India's three-stage nuclear power programme, these reactors will be used to breed uranium-233 from thorium, which can then be used as fuel for nuclear power generation, helping to reduce dependence on uranium imports.

What is the three-stage nuclear power programme?

The three-stage nuclear power programme was designed with the goal of securing energy using India’s limited uranium reserves and one of the largest thorium reserves in the world, as envisioned by Homi J. Bhabha in the 1950s.

In stage 1, natural uranium is used as fuel in pressurized heavy water reactors to generate power. The spent fuel produces plutonium, which becomes the primary input for the next stage.

In stage 2, the plutonium from stage 1 undergoes fission to produce energy and a surrounding uranium "blanket" turns into even more plutonium. Thorium is introduced into the mix and gets converted into uranium. This is the stage that achieved criticality, laying the groundwork for the next stage.

In stage 3, the reactors use uranium to trigger a reaction with thorium, which gets converted into uranium and sustains the reaction. This enables the production of virtually unlimited energy.

What is the current status of nuclear power generation in India?

India has an installed nuclear power generation capacity of 8.78 gigawatts (GW). Nuclear power plants produced 56,681 million units of electricity in 2024-25, equivalent to 3.1% of the total electricity generation. According to the government, India's nuclear capacity is set to grow to 22.38 GW by 2031-32 with indigenous 700-megawatt (MW) reactors and 1,000MW reactors. India has set a target of 100GW of nuclear power capacity by 2047.

What are some of the recent policy measures in the nuclear space?

Parliament passed the Sustainable Harnessing and Advancement of Nuclear Energy for Transforming India (Shanti) Bill, 2025, in December to open up nuclear power generation to the private sector and ease liabilities on suppliers.

In the budget for FY26, the government announced the Nuclear Energy Mission and allocated ₹20,000 crore for the research, design, development and deployment of small modular reactors, aiming to operationalize at least five of them by 2033.

NEW DELHI: India took a major step towards nuclear fuel self-reliance when its indigenously developed Prototype Fast Breeder Reactor (PFBR) at Kalpakkam in Tamil Nadu attained criticality on 6 April. This is the stage when a nuclear chain reaction can sustain itself.

This will enable India to leverage its vast reserves of thorium and reduce dependence on uranium imports. Once the reactor is fully operational, India will become the second country after Russia to have a commercial fast breeder reactor.

Mint looks at the significance of the development as India aims to achieve 100GW of installed nuclear power capacity by 2047.

What is a fast breeder reactor?

A fast breeder reactor is one that produces more fuel than it consumes while generating power. India’s fast breeder reactor was designed and developed by the Indira Gandhi Centre for Atomic Research, the R&D centre of the Department of Atomic Energy. It has a 500-megawatt electrical (MWe) capacity. Unlike conventional thermal reactors, these reactors use uranium, plutonium and thorium as fuel at various stages to generate electricity.

Why is the development significant for India?

Firstly, the technology was indigenously developed after decades of research, design and engineering. Secondly, once fully operational, India will become the second country after Russia to operate a commercial fast breeder reactor. The US, France, the UK, Japan and China have worked on the technology but have not succeeded so far.

Under India's three-stage nuclear power programme, these reactors will be used to breed uranium-233 from thorium, which can then be used as fuel for nuclear power generation, helping to reduce dependence on uranium imports.

What is the three-stage nuclear power programme?

The three-stage nuclear power programme was designed with the goal of securing energy using India’s limited uranium reserves and one of the largest thorium reserves in the world, as envisioned by Homi J. Bhabha in the 1950s.

In stage 1, natural uranium is used as fuel in pressurized heavy water reactors to generate power. The spent fuel produces plutonium, which becomes the primary input for the next stage.

In stage 2, the plutonium from stage 1 undergoes fission to produce energy and a surrounding uranium "blanket" turns into even more plutonium. Thorium is introduced into the mix and gets converted into uranium. This is the stage that achieved criticality, laying the groundwork for the next stage.

In stage 3, the reactors use uranium to trigger a reaction with thorium, which gets converted into uranium and sustains the reaction. This enables the production of virtually unlimited energy.

What is the current status of nuclear power generation in India?

India has an installed nuclear power generation capacity of 8.78 gigawatts (GW). Nuclear power plants produced 56,681 million units of electricity in 2024-25, equivalent to 3.1% of the total electricity generation. According to the government, India's nuclear capacity is set to grow to 22.38 GW by 2031-32 with indigenous 700-megawatt (MW) reactors and 1,000MW reactors. India has set a target of 100GW of nuclear power capacity by 2047.

What are some of the recent policy measures in the nuclear space?

Parliament passed the Sustainable Harnessing and Advancement of Nuclear Energy for Transforming India (Shanti) Bill, 2025, in December to open up nuclear power generation to the private sector and ease liabilities on suppliers.

In the budget for FY26, the government announced the Nuclear Energy Mission and allocated ₹20,000 crore for the research, design, development and deployment of small modular reactors, aiming to operationalize at least five of them by 2033.