Context: Recently, Union Minister of State for Atomic Energy and Space, tolds that Protoype Fast Breeder Reactor (PFBR) being constructed by Bharatiya Nabhikiya Vidyut Nigam Limited (BHAVINI) is expected to get commissioned by October 2022. 
Key Points

• The Prototype Fast Breeder Reactor is being constructed by Bharatiya Nabhikiya Vidyut Nigam Limited (BHAVINI).
• On completion of commissioning, PFBR will be adding 500 MW of electrical power to the national grid.
• The Prototype Fast Breeder Reactor (PFBR) is a 500 MWe fast breeder nuclear reactor presently being constructed at the Madras Atomic Power Station in Kalpakkam, Tamil Nadu. The Indira Gandhi Centre for Atomic Research (IGCAR) is responsible for the design of this reactor.
• The construction started in the year 2004, Originally planned to be commissioned in 2012, the construction of the reactor suffered from multiple delays. As of August 2020, criticality is planned to be achieved in 2021 (now October 2022).
• The reactor is a pool-type reactor with 1,750 tonnes of sodium as coolant.

About Fast Breeder Reactors

• A Fast Breeder Reactor (FBR) is a nuclear reactor that uses fast neutrons to generate more nuclear fuels than they consume while generating power, dramatically enhancing the efficiency of the use of resources.
• Hence, a breeder reactor is a nuclear reactor that generates more fissile material than it consumes.
• It achieves this because its neutron economy is high enough to create more fissile fuel than it uses, by irradiation of a fertile material, such as uranium-238 or thorium-232 that is loaded into the reactor along with fissile fuel.

What is India’s three-phase nuclear power programme?

• The Indian nuclear power programme, launched in 1954, envisaged a three-stage development of nuclear power generation from the country’s uranium and thorium resources.
• The first stage programme consists of setting up of pressurised heavy water reactors (PHWRs). PHWRs are natural uranium-fuelled, heavy water moderated and cooled. The uranium reserves in the country are adequate to support the first stage nuclear power programme of 10,000 MWe through PHWRs. In addition to generating power, PHWRs progressively make available plutonium as a by-product. The technologies for the reprocessing of plutonium from spent PHWR fuel and for fabrication of plutonium bearing fuels have been systematically established in India through research and development over the past several years.
• The second stage of the nuclear power programme consists of effective utilisation of plutonium in Fast Breeder Reactors (FBRs) which will provide the key to full utilisation of the country’s uranium resources and prepare the way for the long-term utilisation of the more abundant thorium reserves. FBRs enable generation of more fresh fissile material than is consumed for power production. With the deployment of FBRs, the depleted uranium and plutonium generated in the first stage will permit an additional power potential to the extent of 3,50,000 MWe.
• During the later part of the second stage programme, it is proposed to use thorium as blanket material in FBRs to generate U-233, another fissile material for use in the third stage programme based on U-233 fuelled reactor systems.