To meet its rapidly growing energy demand, some opine that India should pursue research and development on thorium as the future fuel of nuclear energy. In this context, what advantage does thorium hold over uranium? 1) Thorium is far more abundant in nature than uranium. 2) On the basis of per unit mass of mined mineral, thorium can generate more energy compared to natural uranium. 3) Thorium produces less harmful waste compared to uranium. Which of the statements given above is/are correct?

All three statements hold, so the answer is D. Thorium is roughly three to four times more abundant in the Earth's crust than uranium, and India has large reserves, mainly in monazite sands along the coasts of Kerala, Odisha and Andhra Pradesh. That is why Homi Bhabha's three-stage programme places thorium at its centre.

Statement 2 needs the right logic. Natural uranium is only about 0.7% fissile U-235. Thorium-232 is fertile: it absorbs a neutron and transmutes into fissile U-233, which then fissions. Once bred, U-233 gives a higher neutron yield per absorption in thermal reactors, so the energy extracted per tonne of mined mineral is higher than from natural uranium.

Statement 3 is correct because thorium cycles produce much less plutonium and fewer minor actinides, so the long-lived high-level waste is smaller, though not zero.

For Mains GS-3, this links to energy security and the debate over fuel-cycle choices. Thorium is still not commercially deployed in India; the thorium-based stages remain at the development and research stage.

Trap: Aspirants often reject statement 2 by confusing abundance with energy per tonne, or they assume thorium itself is fissile. It is the breeding to U-233 that makes statement 2 true.