UPSC Prelims 2023 Q11: Uranium Enrichment and Coal Power — Explained
Consider the following statements:
Statement-I:
India, despite having uranium deposits, depends on coal for most of its electricity production.
Statement-II:
Uranium, enriched to the extent of at least 60%, is required for the production of electricity.
Which one of the following is correct in respect of the above statements?
- Both Statement-I and Statement-II are correct and Statement-II is the correct explanation for Statement-I
- Both Statement-I and Statement-II are correct and Statement-II is not the correct explanation for Statement-I
- Statement-I is correct but Statement-II is incorrect
- Statement-I is incorrect but Statement-II is correct
Answer: (c) Statement-I is correct but Statement-II is incorrect
Statement-wise explanation
- Statement-I: correct — Coal produces most of India's electricity. Government data put coal at about 72.5% of total generation in 2023-24, while nuclear power gives only about 3%. India does have uranium: the Atomic Minerals Directorate (AMD) has found deposits in Jharkhand (Jaduguda), Andhra Pradesh (Tummalapalle), Meghalaya, Rajasthan and Karnataka, among other states. But the ore is low-grade and the total is small, so domestic uranium cannot replace coal.
- Statement-II: incorrect — Power reactors do not need uranium enriched to 60%. India's main reactor type, the pressurised heavy water reactor (PHWR), burns natural uranium, which has only about 0.7% U-235 and is not enriched at all. Light water reactors, such as Tarapur 1 & 2 and Kudankulam, use low-enriched uranium with about 3–5% U-235. Uranium at 60% or more counts as highly enriched and is linked to weapons, not power stations. Because Statement-II is false, it cannot explain Statement-I.
- Statement-I: correct — (duplicate guard — ignore)
How to eliminate
Statement-I can be confirmed from basic knowledge. Coal's dominance in Indian power is well known, and uranium mining at Jaduguda is a standard geography fact. That leaves only the options that call Statement-I correct. Statement-II then falls on general knowledge plus its absolute wording: 'at least 60%' makes enrichment a strict condition for producing any electricity. If you know India's PHWRs run on natural, unenriched uranium, the condition fails at once. Another clue: very high enrichment levels such as 60% or 90% appear in the news about nuclear weapons programmes, not power plants. Remember these numbers: natural uranium about 0.7% U-235, power-reactor fuel about 3–5%, weapons-grade about 90%.
Know more
Uranium enrichment raises the share of the fissile isotope U-235. Natural uranium is about 99.3% U-238, which does not split easily, and only about 0.7% U-235.
| Grade | U-235 content | Typical use |
|---|---|---|
| Natural uranium | ~0.7% | PHWRs (CANDU-type), India's main fleet |
| Low-enriched uranium (LEU) | ~3–5% | Light water reactors: BWRs (Tarapur 1 & 2), VVERs (Kudankulam) |
| High-assay LEU | 5–20% | Some research reactors and newer small reactor designs |
| Highly enriched uranium (HEU) | ≥20% | Naval and research reactors |
| Weapons-grade | ~90% | Nuclear weapons |
Why PHWRs need no enrichment: heavy water (D₂O) absorbs very few neutrons. Enough neutrons are left to keep a chain reaction going even with natural uranium. India chose PHWRs in the 1960s so it could use its own mined uranium without building enrichment plants. This is Stage 1 of the three-stage nuclear power programme. Stage 2 uses fast breeder reactors, such as the PFBR at Kalpakkam, which run on plutonium from spent PHWR fuel. Stage 3 aims to use India's large thorium reserves.
Why coal still dominates: India's uranium ore is low-grade and its reserves are modest. Its coal reserves are among the largest in the world. Nuclear plants also cost a lot and take long to build, and for decades the NSG embargo limited India's access to imported fuel. The 2008 NSG waiver opened up imports from Kazakhstan, Russia and Canada. Imported fuel goes to reactors under IAEA safeguards. Nuclear power still supplies only about 3% of India's electricity.
In the news
Iran's enrichment of uranium to 60% U-235 was reported by the IAEA from 2021, and was often in the news in 2022–23. That likely explains why the examiner picked '60%' as a plausible-sounding but wrong figure for power-reactor fuel.
NCERT Concepts to Revise
- Pressurised heavy water reactor: The fuel used by India's main reactor type decides whether enrichment is needed for electricity, the claim in Statement-II.
- Uranium: Statement-I depends on India's uranium deposits and the quality of its ore.
- Three-stage nuclear power programme: Explains why India built its nuclear programme around domestic natural uranium and thorium rather than enrichment.
- Tarapur Atomic Power Station: India's first power station runs on a reactor type with its own fuel needs, useful for testing Statement-II's enrichment claim.
- Nuclear energy: Basic idea of fission of U-235, the isotope whose share enrichment changes.