Why top scientist wants India to move early to thorium fuels, Pg15

Key Highlights:

• Top nuclear scientist Anil Kakodkar advocates for introducing thorium-based fuel into India's indigenous Pressurised Heavy Water Reactor (PHWR) fleet.
• This move aims to accelerate the utilization of India's abundant thorium reserves and enhance self-reliance in nuclear fuel.
• The proposal comes as India plans to deploy around half of its targeted 100 gigawatts-electric (GWe) nuclear capacity through PHWR technology.
• India's first indigenous Fast Breeder Reactor (FBR) at Kalpakkam recently attained criticality, marking a significant milestone in the second stage of the nuclear program.

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Detailed Insights:

• India's three-stage nuclear power programme is designed to achieve long-term fuel self-reliance using its thorium reserves.
• The first stage uses PHWRs with natural uranium, producing plutonium.
• The second stage involves Fast Breeder Reactors (FBRs), which use plutonium and depleted uranium to produce Uranium-233 (U-233) from Thorium-232 (Th-232).
• The third stage will utilize U-233 as fuel in advanced reactors, converting Th-232 directly.
• Kakodkar, former chairman of the Atomic Energy Commission and Chancellor of the Homi Bhabha National Institute, suggests that the growing capacity of PHWRs (up to 50-60 GWe) presents a new opportunity for thorium introduction.
• Previously, thorium was primarily envisaged for FBRs due to limited thermal reactor capacity for efficient conversion.
• The proposal emphasizes ensuring that thorium irradiation in PHWRs does not increase electricity costs or uranium requirements.

Scientific/Technical Concepts Involved:

• Pressurised Heavy Water Reactor (PHWR): A nuclear reactor type that uses heavy water as both coolant and neutron moderator, typically fueled by natural uranium.
• Fast Breeder Reactor (FBR): A nuclear reactor that produces more fissile material than it consumes, using fast neutrons to breed new fuel.
• Thorium-232 (Th-232): A naturally occurring, fertile isotope of thorium that can be converted into fissile Uranium-233 in a nuclear reactor.
• Uranium-233 (U-233): A fissile isotope of uranium, not found in nature, produced by neutron irradiation of Thorium-232.
• Criticality: The state in a nuclear reactor where a self-sustaining nuclear fission chain reaction is achieved.