RAS question
What is the significance of thorium in India's nuclear energy strategy?
Correct answer: (A) India has the world's largest reserves of thorium and plans to use it in Stage 3 of its nuclear programme.
Thorium is significant in India's nuclear energy strategy because India has a major share of the world's thorium reserves and plans to use Thorium-232 in Stage 3 of its nuclear programme through Advanced Heavy Water Reactors that breed Uranium-233.
Explanation
India's thorium strategy rests on resource security and reactor sequencing. India has about 25% of the world's thorium reserves, estimated at 9,63,000 tonnes, mainly in monazite sands along the Kerala and Odisha coasts. The PIB release supports the programme logic: naturally occurring thorium has no fissile isotope, so its large-scale commercial use depends on fissile material bred from earlier stages. That is why Stage 3 comes after sufficient capacity from Fast Breeder Reactors in Stage 2. In Stage 3, Advanced Heavy Water Reactors are envisaged as technology demonstrators for thorium-based fuel, where Thorium-232 is converted into fissile Uranium-233.
Why the other options are wrong
- (B) Thorium is treated as a nuclear fuel resource in India's strategy, not as a coolant; it is linked to Thorium-232 and Uranium-233, not heat removal.
- (C) Thorium clearly has a role because the PIB release says its utilisation is contemplated in the third stage of the Indian nuclear programme.
- (D) Thorium is framed as India's strategic energy reserve for Stage 3, not as a material exported for weapons.
Concept
This tests India's three-stage nuclear power programme, especially the link between domestic thorium resources, Fast Breeder Reactors and Uranium-233. It recurs in RAS because it combines science policy, energy security and India's resource geography.