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? [2012]

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?

Thorium is far more abundant in nature than uranium.
On the basis of per unit mass of mined mineral, thorium can generate more energy compared to natural uranium.
Thorium produces less harmful waste compared to uranium.

Thorium is three to four times more abundant than uranium in the Earth’s crust.

Thorium is weakly radioactive and all its known isotopes are unstable, including the seven naturally occurring ones (thorium-227, 228, 229, 230, 231, 232, and 234).
Thorium-232 is the most stable isotope of thorium and accounts for nearly all natural thorium.
Its most common source is the rare earth mineral monazite (monazite contains 2.5% thorium).
Other important sources are minerals such as thorite and thorianite
India has the world’s largest Thorium resource of around 1 million tonnes, followed by Brazil, Australia, the USA, and Egypt. Because of this resource position, India has chalked out a Three-Stage Nuclear Power Programme where thorium plays a significant role.

In terms of energy yield, thorium can produce more energy per unit mass of mined mineral than natural uranium. This is because natural uranium contains only about 0.7% fissile U-235, whereas thorium-232 is a fertile material that can be converted into fissile U-233, enabling more efficient fuel use and higher burn-up.