Understanding the Prototype Fast Breeder Reactor (PFBR)

GS PAPER III: SCIENCE AND TECHNOLOGY – NUCLEAR ENERGY AND SELF-RELIANCE

PROTOTYPE FAST BREEDER REACTOR (PFBR): A LEAP TOWARD ENERGY INDEPENDENCE

1. What is the PFBR?

The Prototype Fast Breeder Reactor (PFBR) at Kalpakkam, Tamil Nadu, is a 500 megawatt-electric (MWe) nuclear power reactor being developed by the Indira Gandhi Centre for Atomic Research (IGCAR) and Bharatiya Nabhikiya Vidyut Nigam Ltd (BHAVINI). It represents a major milestone in India’s three-stage nuclear programme, aimed at achieving self-sufficiency in nuclear fuel and ensuring long-term energy independence.

2. How does a Fast Breeder Reactor work?

A Fast Breeder Reactor (FBR) is unique because it produces more nuclear fuel than it consumes. It uses Plutonium-239 as its primary fuel and liquid sodium as the coolant.

Unlike conventional reactors that slow down neutrons using water, fast reactors maintain high-speed neutrons. These fast-moving neutrons convert Uranium-238 (non-fissile) into Plutonium-239 (fissile), thereby creating new fuel in a process known as “breeding.”

This process allows the reactor to generate additional fuel while minimizing nuclear waste, making it a more efficient and sustainable form of nuclear energy.

3. Why is liquid sodium used instead of water?

In a fast reactor, water is unsuitable as it slows down neutrons. Instead, liquid sodium is used because it:

• Does not slow down neutrons.
• Has excellent heat-transfer properties.
• Allows higher operating temperatures, improving efficiency in electricity generation.

However, sodium reacts strongly with air and water, so the PFBR includes advanced safety systems to contain and manage sodium securely.

4. What is “First Criticality”?

First criticality refers to the moment when a controlled, self-sustaining nuclear chain reaction begins for the first time inside the reactor. For the PFBR, this milestone is expected by mid-2026, following the start of fuel loading on 18 October 2025. Achieving criticality marks the transition from construction to operational status.

5. Why is the PFBR important for India?

Once operational, India will become only the second country after Russia to operate a functional fast breeder reactor. The PFBR will:

• Reduce dependence on imported uranium.
• Recycle spent fuel, thereby minimizing radioactive waste.
• Advance India’s goal of energy security through indigenous technology.
• Pave the way for the thorium-based third stage of India’s nuclear programme.

6. What is the Thorium Advantage?

India possesses one of the world’s largest thorium reserves. Although thorium itself cannot start a nuclear reaction, it can be converted into Uranium-233 (a fissile material) when irradiated in a reactor.

In the future, the PFBR’s outer blanket will contain thorium-232, which will be transformed into Uranium-233, enabling the Stage III thorium cycle. This will ensure a sustainable, long-term source of nuclear energy for India.

7. What about Safety and Waste Management?

The PFBR is equipped with multiple passive safety systems designed to automatically shut down the reactor in abnormal conditions. It also features a closed fuel cycle — reusing spent fuel to minimize radioactive waste and reduce the need for large disposal sites.

Such measures ensure both environmental safety and operational reliability.

8. How does this fit into India’s nuclear vision?

Under the Nuclear Energy Mission for Viksit Bharat, India aims to expand its nuclear capacity from 8.18 GW to 100 GW by 2047. The PFBR is a cornerstone in this journey, demonstrating India’s capability to design, build, and operate advanced nuclear reactors indigenously.

It represents a transformative step toward a clean, efficient, and self-reliant energy future, aligning with India’s broader goals of sustainable development and technological leadership.