RAS question
The Prototype Fast Breeder Reactor (PFBR) at Kalpakkam uses which fuel?
Correct answer: (C) MOX (Mixed Oxide) fuel with plutonium and uranium.
The Prototype Fast Breeder Reactor at Kalpakkam uses Uranium-Plutonium Mixed Oxide fuel, commonly called MOX fuel.
Explanation
The PFBR at Kalpakkam belongs to the fast breeder reactor stage of India's three-stage nuclear power programme, not to the conventional thermal-reactor category. The official PIB factsheet states that, unlike conventional thermal reactors, the PFBR uses Uranium-Plutonium Mixed Oxide fuel. This fits the logic of Stage 2: plutonium obtained from Stage 1 spent fuel becomes the fuel input for fast breeder reactors, which are designed to generate more fuel than they consume. This MOX fuel is a mixture of plutonium-239 and uranium-238 oxides, with liquid sodium used as coolant. The breeder design matters because fast neutrons convert fertile uranium-238 into fissile plutonium-239, making the reactor a bridge between uranium-based power and the later thorium stage.
Why the other options are wrong
- (A) Natural uranium is associated with Stage 1 Pressurised Heavy Water Reactors, whereas the PFBR is a Stage 2 fast breeder reactor using MOX fuel.
- (B) Enriched uranium is not the PFBR fuel; the PIB factsheet specifies Uranium-Plutonium Mixed Oxide fuel.
- (D) Thorium-232 belongs to the later thorium pathway and is planned for the third stage, while the PFBR's operating fuel is Uranium-Plutonium MOX.
Concept
This tests India's three-stage nuclear power programme and the reactor-fuel match within Science and Technology. It recurs in RAS because PFBR links nuclear energy, indigenous technology and the uranium-to-thorium transition in one compact concept.