Source: NDTV
Subject: Science and Technology
Context: Prime Minister of India congratulated scientists as India’s first indigenous Prototype Fast Breeder Reactor (PFBR) at Kalpakkam, Tamil Nadu, successfully attained criticality.
About India First Fast Breeder Reactor (FBR) Achieve Criticality:
What is Fast Breeder Reactor (FBR)?
- A Fast Breeder Reactor is an advanced nuclear reactor that generates more fissile material (fuel) than it consumes while producing electricity. It is fast because it uses high-energy (fast) neutrons to sustain the fission chain reaction, unlike conventional reactors that use slow neutrons.
What is Criticality?
- In nuclear physics, criticality is the state in which a nuclear fuel sustains a self-supporting chain reaction. It is the point at which the number of neutrons produced by fission is exactly equal to the number of neutrons lost (through leakage or absorption) plus those causing new fissions.
Developed By: The 500 MWe PFBR has been developed by Bharatiya Nabhikiya Vidyut Nigam Ltd (BHAVINI).
How It Works?
- Fuel: It uses a Uranium-Plutonium Mixed Oxide (MOX) fuel.
- The Breeding Process: The reactor core is surrounded by a blanket of fertile material (Uranium-238). When these U-238 atoms capture fast neutrons, they undergo transmutation to become Plutonium-239, which is a high-grade nuclear fuel.
- Coolant: Instead of water, it uses Liquid Sodium as a coolant because sodium does not slow down neutrons, allowing the fast reaction necessary for breeding.
- Heat Exchange: The heat generated by fission is transferred to the liquid sodium, which then heats water to produce steam to turn turbines.
Aim:
- To create a surplus of Plutonium fuel to power future fast reactors.
- To act as a bridge to the third stage of India’s nuclear programme, where Thorium-232 will be converted into Uranium-233.
- To provide a sustainable, long-term solution to India’s energy needs by extracting significantly more energy from uranium than conventional reactors.
Key Features:
- Indigenous Design: Built almost entirely with Indian technology and materials.
- MOX Fuel Technology: Utilizes recycled fuel from the first stage (Pressurized Heavy Water Reactors).
- Passive Safety: Equipped with advanced safety systems that can automatically shut down the reactor during emergencies without human intervention.
- High Efficiency: Operates at higher temperatures than conventional reactors, leading to better thermal efficiency.
Significance:
- Attaining criticality is the final scientific green light before the reactor begins generating electricity for the grid.
- It proves that the reactor’s core geometry, fuel arrangement, and engineering calculations are accurate and functional.
- For India, PFBR criticality signals the formal operational start of the Second Stage of its nuclear roadmap, moving the country closer to utilizing its vast thorium reserves.
