India must shift to thorium-based nuclear energy to secure long-term fuel supply

📌 Summary:

• India has launched a 100 GWe nuclear energy mission (Pressurised Heavy Water Reactors — PHWRs) to be achieved by 2047 under the Viksit Bharat framework.

• PHWRs are identified as the most mature and commercially competitive technology for rapid scaling; 9 new PHWRs were cleared in Budget 2026-27.

• Uranium supply risk: The steep increase in uranium imports is a major concern — global uranium demand is projected to grow 3-4x due to nuclear renaissance globally; India faces fuel supply security risk within 10-15 years.

• Case for thorium: India possesses the world's third-largest thorium reserves (approximately 25% of global reserves in monazite sands of Kerala, Tamil Nadu, Odisha beaches) — making a shift critical for energy sovereignty.

• How thorium works in nuclear: Thorium-232 is not fissile itself; it breeds Uranium-233 (U-233) in a reactor using neutron absorption — U-233 then powers further reactions. This is the basis of India's Three-Stage Nuclear Programme.

• Three-Stage Programme: Stage 1 (PHWRs using natural uranium) → Stage 2 (Fast Breeder Reactors using plutonium; breeds U-233 from thorium) → Stage 3 (Advanced Heavy Water Reactors using U-233 and thorium).

• Proliferation advantage: Thorium-U-233 fuel cycle has inherent proliferation resistance compared to uranium-plutonium cycle — making it safer globally.

• Once thorium systems are available, India could sustain nuclear energy until fusion power arrives.

• The world has restricted uranium to once-through mode due to proliferation fears — reducing usable energy potential by two orders of magnitude for most countries.

🎯 UPSC Relevance: GS3 — Science & Technology (Nuclear energy); also GS3 Indian Economy (energy security); the Three-Stage Nuclear Programme is a flagship UPSC topic.

📝 Prelims Facts:

• India's thorium reserves: ~25% of world's total; found in monazite sand along Kerala-Tamil Nadu coast.
• Three-Stage Nuclear Programme: conceived by Dr. Homi J. Bhabha in the 1950s.
• Thorium-232 → (neutron absorption) → Protactinium-233 → Uranium-233 (fissile).
• Kudankulam (Tamil Nadu) and Kakrapar (Gujarat): India's key nuclear power plants.

🔑 Key Term: Three-Stage Nuclear Programme — India's long-term nuclear energy strategy: Stage 1 (PHWRs), Stage 2 (Fast Breeders), Stage 3 (thorium-based reactors), designed to leverage India's vast thorium reserves for energy independence.