Nuclear Power Plants in India: Three-Stage Programme and UPSC Notes (UPSC Environment)

Nuclear power is a low-carbon, high-energy-density source that delivers firm baseload electricity around the clock. India has 23 operational reactors totalling 7,480 MW and several under construction. The country follows a unique Three-Stage Nuclear Programme conceptualised by Dr Homi Bhabha in the 1950s to eventually tap its vast thorium reserves. After the 2024-25 Budget announced support for Small Modular Reactors (SMRs) and Bharat Small Reactors (BSRs), nuclear power is firmly back on the UPSC GS Paper III agenda under energy, science and technology.

Nuclear plants compared to thermal and hydro

Nuclear power plant

• Location: Isolated areas away from population for safety.
• Initial cost: Highest, because of reactor and containment construction.
• Running cost: Low, as fuel quantity is small.
• Fuel: Uranium (enriched or natural), later plutonium and eventually thorium.
• Fuel transport cost: Minimum, because quantity is small.
• Environmental impact: Better than thermal but concerns about radioactive waste and potential accidents.
• Efficiency: Higher than thermal, around 33 percent for most pressurised water reactors.
• Maintenance: Highest; needs highly skilled workers.
• Standby losses: Less than thermal because they run at steady state.

Thermal power plant

• Location: Where coal, water and transport are adequate.
• Initial cost: Lower than hydro and nuclear.
• Running cost: Higher than nuclear because of large coal requirement.
• Fuel: Coal (dominant), gas, diesel.
• Fuel transport cost: Highest, because of large coal volumes.
• Environmental impact: Least environment-friendly; major source of SO2, NOx, PM and CO2.
• Efficiency: Around 25 percent overall for subcritical, up to 42 percent for supercritical.
• Maintenance cost: Very high.
• Standby losses: Maximum, because boilers keep running even when turbines are idle.

Hydro power plant

• Location: Hilly areas where large reservoirs or dams can be created.
• Initial cost: High due to dam construction.
• Running cost: Practically nil; no fuel required.
• Fuel: Water, dependent on rainfall and snowmelt.
• Fuel transport cost: None.
• Environmental impact: Most environment-friendly in operation, but dams have ecological and social costs.
• Efficiency: Around 85 percent, highest among conventional generation.
• Maintenance: Lowest among the three.
• Standby losses: None.

Nuclear power in India

Current capacity

• 23 reactors, 7,480 MW installed as of early 2025.
• Plants: Tarapur (Maharashtra), Rajasthan Atomic Power Station (Rawatbhata), Kakrapar (Gujarat), Kaiga (Karnataka), Narora (Uttar Pradesh), Madras Atomic Power Station (Kalpakkam, Tamil Nadu) and Kudankulam (Tamil Nadu, Russian cooperation).
• Kudankulam Units 3 and 4 are under construction with Russian cooperation.
• Gorakhpur Haryana Anu Vidyut Pariyojana (GHAVP), Mahi Banswara (Rajasthan), Kaiga 5 and 6 are planned.
• Target: Triple nuclear capacity to over 22,000 MW by 2032.

Regulator

• Nuclear Power Corporation of India Limited (NPCIL): Owns and operates reactors.
• Department of Atomic Energy (DAE): Policy and planning.
• Atomic Energy Regulatory Board (AERB): Safety regulator.

India's Three-Stage Nuclear Programme

Conceptualised by Dr Homi Bhabha to use India's limited uranium reserves but vast thorium reserves (about 25 percent of global thorium).

Stage 1: Pressurised Heavy Water Reactors (PHWRs)

• Fuel: Natural uranium (U-238 plus U-235).
• Moderator and coolant: Heavy water.
• Output: Electricity and plutonium-239 as by-product.
• Most of India's operating reactors.

Stage 2: Fast Breeder Reactors (FBRs)

• Fuel: Plutonium-239 (from Stage 1) mixed with uranium.
• Produces more fissile material (plutonium) than it consumes (hence "breeder").
• Uses U-238 blanket that converts to plutonium, and thorium blanket that converts to U-233.
• Prototype Fast Breeder Reactor (PFBR) at Kalpakkam, 500 MW, achieved first criticality in March 2024.

Stage 3: Thorium-based reactors

• Fuel: U-233 produced in Stage 2 combined with thorium.
• Advanced Heavy Water Reactor (AHWR) designed by BARC for thorium use.
• Not yet commercial.

Small Modular Reactors (SMRs) and Bharat Small Reactors (BSRs)

What are SMRs

SMRs are advanced reactors with capacity up to 300 MW per unit. Features:

• Smaller footprint.
• Factory-built modules, assembled on site.
• Lower capital cost per unit.
• Passive safety features.
• Suitable for remote or industrial decarbonisation applications.

Bharat Small Reactors

The 2024-25 Union Budget announced Bharat Small Reactors, private-sector participation in nuclear, and R&D for advanced reactor designs. The objective is to make nuclear a larger share of India's 500 GW non-fossil capacity target for 2030 and beyond.

Civil nuclear cooperation

• India-US Civil Nuclear Agreement (2008) opened international cooperation.
• Nuclear Suppliers Group waiver allowed imports of reactors, fuel and technology.
• Bilateral agreements with Russia (Kudankulam), France (Jaitapur, planned), Canada (PHWR components), Japan, Australia and others.
• International Atomic Energy Agency (IAEA) safeguards on civil facilities.

Challenges

• Long gestation: New nuclear plants take 7 to 10 years to build.
• Capital cost: Higher than most alternatives per MW.
• Public acceptance: Fukushima effect and local protests (Kudankulam, Jaitapur).
• Radioactive waste: Long-term storage and disposal.
• Nuclear liability: Civil Liability for Nuclear Damage Act 2010 creates supplier liability concerns that have slowed foreign collaboration.
• Fuel security: Requires reliable uranium imports; domestic uranium reserves are modest.

Way forward

• Accelerate SMR deployment for industrial decarbonisation.
• Amend nuclear liability framework to unlock private and foreign investment.
• Complete PFBR Kalpakkam operations to validate Stage 2.
• Invest in thorium-based research reactors.
• Expand uranium supply through international partnerships and domestic exploration.
• Engage communities around new sites with transparent consultation.

Latest developments (2024-26)

• PFBR first criticality achieved at Kalpakkam in March 2024, a landmark for Stage 2.
• Bharat Small Reactors announced in 2024-25 Budget; private sector participation in nuclear R&D approved.
• Jaitapur (France cooperation) agreements progressing with EDF; final contracts expected in 2025-26.
• Kudankulam Units 3 and 4 commissioning expected in 2025 and 2026.
• Amendment to Civil Liability for Nuclear Damage Act: Under consideration to resolve supplier liability concerns.
• COP29 Baku (2024): Nuclear was recognised under the Declaration to Triple Nuclear Energy by 2050; India participated in discussions.
• IAEA support: Continued IAEA collaboration on safety and safeguards.
• Fusion research: ITER partnership and domestic fusion research at Institute for Plasma Research.

UPSC Relevance

Prelims focus

• Three-Stage Nuclear Programme (Bhabha): PHWR → FBR → Thorium.
• PFBR Kalpakkam, 500 MW, first criticality March 2024.
• Operational reactors: 23 totalling 7,480 MW; target 22,000 MW by 2032.
• NPCIL, DAE, AERB.
• Bharat Small Reactors (Budget 2024-25).
• India-US Civil Nuclear Agreement 2008.
• Civil Liability for Nuclear Damage Act 2010.

Mains focus (GS III)

Typical question framings evaluate India's nuclear programme, the relevance of SMRs for net-zero, the liability law debate, and the thorium-based future. Strong answers cite the three-stage programme, specific plants, international cooperation, and climate policy.

Linkages

Nuclear power connects to SDG 7, SDG 13, India's updated NDCs after COP29, the Paris Agreement, the IAEA framework, the Treaty on the Non-Proliferation of Nuclear Weapons context, the Nuclear Suppliers Group waiver, and the Indian Carbon Market.