RAS question
Nuclear reactors commonly use which element as fuel?
Correct answer: (B) Uranium.
Nuclear reactors commonly use uranium, especially uranium-235 in commercial reactors, as their fuel.
Explanation
Uranium is the answer because nuclear power reactors run on fission: uranium atoms are split, releasing heat that is used in nuclear power plants. The U.S. Environmental Protection Agency identifies uranium as the fuel most widely used in nuclear reactors at power plants, and separately identifies enriched uranium as fuel found at nuclear power plants. This fits the standard exam framing that uranium-235 is the most commonly used nuclear fuel in commercial reactors worldwide. Thorium matters for India because India's three-stage nuclear power programme aims eventually to use thorium, drawing on large domestic reserves, but that future-oriented programme does not change the present common reactor fuel.
Why the other options are wrong
- (A) Thorium can be used as a nuclear fuel and is important in India's long-term three-stage programme, but the question asks what reactors commonly use now, and that is uranium.
- (C) Plutonium is associated with breeder-reactor fuel use, but uranium-235 is the most commonly used commercial reactor fuel.
- (D) Radium is radioactive, but reactor fuel use points to uranium, not radium.
Concept
This tests the Science and Technology syllabus area on nuclear energy and fission fuels. It recurs in RAS because India's uranium use and thorium ambitions are often tested together.