India’s Nuclear Energy Program- Explained Pointwise

On April 6, 2026, India achieved a major milestone in its nuclear programme as the Prototype Fast Breeder Reactor at Kalpakkam, Tamil Nadu reached criticality-successfully sustaining a controlled nuclear fission chain reaction for the first time.

With this, India joins a select group of nations with advanced fast breeder reactor technology, and once fully operational, it will become only the second country after Russia to run a commercial fast breeder reactor. Nuclear Energy program in India UPSC

What is India’s three-stage nuclear energy program?

Historical Background- The roadmap of India’s three-stage nuclear program was envisioned by Dr. Homi J Bhabha. The program had been conceived with the ultimate objective of utilising the country’s vast reserves of thorium-232. India hosts roughly a quarter of the world’s thorium, and the three stages are expected to make the country completely self-sufficient in nuclear energy.

Three-stage Nuclear Energy Program

Working of 3-Stages

Stage I
a. In the Stage-I, India used the Pressurized Heavy Water Reactors (PHWRs) with natural uranium-238 (U-238) as the fuel. The U-238 contained minuscule amounts of U-235, as the fissile material.

b. A nuclear fission process was initiated and heavy water (water molecules containing the deuterium isotope of hydrogen) slowed the release of neutrons released by one fission reaction enough to be captured by other U-238 and U-235 nuclei and cause new fission.

c. The reactions produce fissile Plutonium-239 (Pu-239) and energy.

Stage II
a. Only U-235 can sustain a chain fissile reaction. However, it is consumed fully in stage I. Hence, Stage II aims at using the fissile Plutonium-239 (Pu-239) produced as the end product of Stage I with U-238 to produce energy, U-233 and more Pu-239.

b. By the end of the second stage of the cycle, the reactor produces more fissile material than it consumes. Hence, it is called a ‘Breeder‘ reactor. In these ‘fast breeder’ reactor, the neutrons aren’t slowed.

Stage III
a. It focuses on combining Pu-239 with thorium-232 (Th-232) in advanced heavy water reactors to produce energy and U-233.

b. This stage uses the naturally available thorium-232 in India and hence will help in achieving nuclear energy self-sufficiency.

What are the important milestone events in India’s Nuclear Energy Program?

The establishment of several institutions has played a critical role in driving India’s Nuclear Energy Program.

Passive Phase

However, India did not sign the NPT in 1970, did not become a member of the NSG in 1974. After India’s first nuclear Test, Smiling Buddha in 1974, there was widespread condemnation from the international community. There was international apartheid against India in supply of nuclear fuel.

Active Phase

What are the advantages of India’s Nuclear Energy Programme?

1. Energy Sovereignty- Fossil-based energy sources contributed about 82% of the primary energy supplied in 2021. India imports a significant part of its fossil fuels (coal and gas) for energy generation. Bulk fuel imports raise economic and strategic vulnerabilities for a developing country like India. Nuclear energy can help India reduce its dependence on imported fuel.

2. Decarbonisation of power Sector- Thermal power plants have high carbon footprint as they contribute heavily to global warming, climate change and air pollution. Nuclear power plants will help in decarbonising the power sector.

3. Limitations attached with other renewable energy sources- Solar energy is land intensive, wind energy requires energy storage systems. Also, they require imported technologies and materials such as photovoltaic cells, batteries, and storage equipment. On the other hand, indigenous nuclear reactors have reduced dependency in critical imports.

4. Cheaper to Operate- Nuclear power plants are cheaper to operate than coal or gas plants, despite the cost of managing radioactive fuel and disposal. According to estimates, nuclear plants cost only 33-50% of a coal plant and 20-25% of a gas combined-cycle plant.

5. Reliable and Continuous Power- Nuclear energy provide reliable and continuous base load power, unlike solar and wind energy, which are intermittent and dependent on weather conditions.

6. Resource Base- India has vast thorium reserves which could be exploited using a thermal breeder reactor. A significant amount of thorium reserves are found in the monazite sands of coastal regions of South India.

What are the challenges to India’s Programme?

1. Capital Intensive- Nuclear power plants are capital intensive. There have been cost over runs in recently built nuclear power plants.

2. Insufficient Installed Capacity- As of 2025–26, India’s installed nuclear power capacity is about 8,780 MW across 24 reactors, against a target of 100 GW by 2047 under the Nuclear Energy Mission.

3. Nuclear Safety- Local communities in India have been resisting nuclear reactors due to fears of nuclear disasters like Chernobyl, 1986 or Fukushima, 2011. For ex- Locals protesting against the Mithi virdi nuclear project in Gujarat.

4. Nuclear Liability-  Civil Liability for Nuclear Damage Act, 2010 had been a long-standing deterrent to foreign suppliers due to unlimited supplier liability. The SHANTI Act, 2025 now replaces it with a graded, capped liability framework – removing automatic supplier liability and introducing tiered operator caps based on reactor size. However, opposition parties have raised concerns about dilution of supplier accountability.

5. Hurdles created by NSG and NPT- India’s non-ratification of NPT and lack of NSG membership, has created diplomatic hurdles in accessing more nuclear fuel and better nuclear technologies.

6. Use of outdated Technology- Currently operational Indian nuclear reactors have become outdated and suffer from multiple operational probles. For ex- 6 VVER (water-water energy reactor) design reactors encountering operational problems at Kudankulam.

What should be the way Forward?

1. Small Modular Reactors (SMRs)– Indigenous Small Modular Reactors (SMRs) must be built at coal plant sites which would be retiring in the coming decades. SMRs offer the advantages of being safe, economical, compact and adaptable. Partnerships with NTPC and other thermal plant owners must be explored.

2. Expansion of indigenous PHWR reactors- The Indigenous 700 MWe PHWR, must be expanded in fleet mode to add to the installed nuclear power capacity in India.

3. Scale up the Fast Breeder Reactor programme – With the PFBR achieving criticality in 2026, two additional FBRs must now be constructed at Kalpakkam, followed by four more beyond 2030. This will consolidate Stage II and generate sufficient U-233 from thorium blankets to fuel Stage III reactors.

4. Accelerate Stage III – Advanced Heavy Water Reactor (AHWR) – Design validation and peer review of the AHWR is ongoing. The project must be formally launched at the earliest to utilise India’s vast thorium reserves, estimated to sustain energy needs for around 60,000 years.

5. Augmentation of safety of nuclear facilities- There must be constant updation of safety skills of nuclear operators. Further, masses must be comprehensively sensitised about the functioning of nuclear power plants using highly intellectual individuals having mass appeal. For ex- Dr. APJ Abdul Kalam sensitizing the masses before the establishment of the Kudankulam nuclear power plant.

6. Ensuring Regulatory Autonomy- The AERB, India’s nuclear regulatory body, must be provided functional autonomy by removing its reporting from the Department of Atomic Energy (DAE).