Thorium
Let’s begin with a question that might come in both prelims and mains:
Why does India give so much importance to Thorium, even though Uranium is used as nuclear fuel today?
The answer lies in a combination of resource availability, reactor design, and strategic foresight—as we shall now explore.
What is Thorium?
Thorium is a weakly radioactive metallic element, present in the Earth’s crust in considerable abundance. Unlike uranium, it is not fissile by itself, but it has one game-changing feature:
➡️ Thorium-232, the most stable and naturally abundant isotope of thorium, can be converted into fissile Uranium-233 through a nuclear reaction.
This transformation is the foundation for thorium’s use in reactors.
Quick Facts on Thorium
| Property | Detail |
|---|---|
| Isotopes | 7 natural (e.g., Th-227, Th-228, Th-232), all unstable |
| Most stable & common | Thorium-232 |
| Radioactivity | Weak, compared to uranium |
| Abundance | 3 to 4 times more abundant than uranium in the Earth’s crust |
| Main source mineral | Monazite (contains ~2.5% thorium) |
| Other sources | Thorite, Thorianite |
Thorium as a Nuclear Fuel
This is where it gets strategically exciting for India.
Thorium cannot be used directly as a nuclear fuel because it is not fissile. But when it absorbs a neutron, it gets converted into Uranium-233, which is fissile.
So, it needs to be “kickstarted” using either:
- Uranium-235, or
- Plutonium-239
Once started, a self-sustaining nuclear chain reaction can be achieved in specially designed reactors.
India’s Three-Stage Nuclear Power Programme
India’s nuclear journey is uniquely structured with Thorium in mind. Let’s break it down:
| Stage | Focus | Fuel Used | Reactor Type |
|---|---|---|---|
| Stage I | Energy production from natural uranium | Uranium-238 & 235 | PHWR (Pressurised Heavy Water Reactors) |
| Stage II | Use of plutonium produced in Stage I | MOX fuel (U+Pu) | Fast Breeder Reactors (FBRs) |
| Stage III | Large-scale thorium utilisation | Thorium-232 → U-233 | Advanced Heavy Water Reactors (AHWRs) |
🔸 Stage III is where thorium becomes the hero, but India is still preparing the technological infrastructure and fissile material (U-233) needed for this leap.
ANEEL Fuel: A Game-Changer
Now let’s talk about ANEEL (Advanced Nuclear Energy for Enriched Life)—a futuristic development relevant to India.
- Developed by Clean Core (Chicago-based company)
- It combines Thorium + HALEU (High Assay Low Enriched Uranium)
- Compatible with India’s existing PHWRs, so no major reactor redesign is needed
Benefits of ANEEL Fuel
- ✅ Supports India’s goal to triple nuclear energy capacity by 2030
- ✅ Higher burn-up rate → Less nuclear waste
- ✅ non-weaponizable spent fuel → addresses non-proliferation concerns
- ✅ Boosts energy security while aligning with clean energy goals for 2047 (India @100)
Global Distribution of Thorium
India’s thorium advantage becomes clearer when we look at global reserves:
| Country | Reserves (approx.) | Reserves (in ‘000 tonnes) |
| India | ~1 million tonnes (largest) | 846 |
| Brazil | Coastal regions – Espirito Santo, Rio de Janeiro, Sao Paulo | 632 |
| Australia | Monazite & xenotime – Murray & Eucla Basins | 595 |
| USA | Idaho, Colorado (Wet Mountains), Wyoming | 595 |
| Canada | Quebec, Ontario, Northwest Territories | 172 |
| Others | China, Turkey, Norway, Russia |
Thorium in India: Abundance & Strategic Value
Major Deposits of Thorium in India
Let’s categorise thorium-rich regions geographically:
1. Eastern Coast (richest belt)
- Tamil Nadu – Manavalakurichi (most concentrated)
- Andhra Pradesh, Odisha
2. Western Coast
- Kerala – especially the monazite sands (major contributor)
- Maharashtra, Gujarat
3. Inland Deposits
- Jharkhand, Rajasthan, Chhattisgarh
🧠 Note: These thorium reserves are mainly associated with monazite-rich beach sands, which also contain rare earth elements (REEs) and uranium in trace amounts.
India’s Resource Position
| Element | Availability in India |
| Uranium | Scarce, low-grade, scattered |
| Thorium | Abundant, high-grade, concentrated |
This is exactly why India envisions thorium as the fuel of the future.
But here’s the catch: using thorium is technologically complex and requires fissile material to initiate. That’s why India has patiently structured its nuclear programme in three stages.
Current Status of Thorium Reactors Globally
- Very few thorium reactors are currently operational.
- Most countries are still in experimental or pilot phases.
- India is among the few nations actively pursuing thorium-based reactor development, particularly through its AHWR programme.
Conclusion: Thorium and India’s Energy Future
Thorium offers a sustainable, abundant, and geopolitically secure option for India’s nuclear energy needs.
Its advantages include:
- High availability in India
- Lower radioactive waste
- Non-proliferation benefits
- Potential to support long-term clean energy transition
But the path is technologically demanding and capital-intensive.
Still, if India successfully operationalises Stage III, it can become a global leader in thorium-based nuclear energy, setting an example of strategic resource utilisation and clean energy leadership.
