Prelims 2012 · archive
MediumTo 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?
Answer & explanation
Answer: (d) 1, 2 and 3
All three statements are correct. Thorium is three to four times more abundant in nature than uranium. Natural thorium is entirely fertile Th-232, which can be bred into fissile U-233, while natural uranium has only about 0.7% fissile U-235. Thorium-fuelled reactors also produce less long-lived nuclear waste than present-day uranium-fuelled reactors.
- ✓ 1. The IAEA states that thorium is three to four times more abundant in nature than uranium.
- ✓ 2. Natural uranium contains only about 0.7% fissile U-235, and conventional reactors essentially use only this fraction. Natural thorium is made up entirely of fertile Th-232. Once bred into fissile U-233, all of it is potentially usable, so per unit mass of mined mineral thorium can in principle yield more energy.
- ✓ 3. The IAEA notes that thorium-fuelled reactors produce less long-lived nuclear waste than present-day uranium-fuelled reactors.
Remember · Thorium: 3–4 times more abundant than uranium; fertile Th-232 breeds fissile U-233; less long-lived waste. India's three-stage nuclear programme ends with thorium in its third stage, because India has large thorium but limited uranium reserves.
Sources
- IAEA – Thorium's Long-Term Potential in Nuclear Energy: New IAEA Analysis ↗ “It is three to four times more abundant in nature than uranium but historically has found little use in industry or power generation.”
- IAEA Bulletin – Thorium's Long-Term Potential in Nuclear Energy ↗ “another advantage is that they produce less long-lived nuclear waste than present-day uranium-fuelled reactors.”
- IAEA-TECDOC-1450, Thorium fuel cycle – Potential benefits and challenges (2005) ↗ “Unlike natural uranium, which contains ~0.7% 'fissile' 235U isotope, natural thorium does not contain any 'fissile' material and is made up of the 'fertile' 232Th isotope only.”
Question: UPSC Civil Services (Preliminary) 2012, General Studies paper. Explanation: Minimalist IAS, checked 25 Oct 2026 (how we verify). ·