Attaining Criticality: India's Prototype Fast Breeder Reactor Program 

Digging Into the Achievement 

- Atomic Energy Regulatory Board (AERB) has given the nod to the "First Approach to Criticality" of India's first 500 MWe Prototype Fast Breeder Reactor (PFBR) stationed at Kalpakkam, Tamil Nadu.

- Criticality, in the terms of a nuclear reactor, signifies a state wherein the neutrons produced by fission replace those lost in leakage or absorption, maintaining constant neutron levels. 

The Inside Story of India's FBR Programme

- The initiative to build an FBR started about two decades ago, adding to India's capabilities in the entire nuclear fuel cycle where uranium is the primary source for electricity production in nuclear power plants. 

- The Department of Atomic Energy (DAE) has set a goal to augment the proportion of nuclear power in the country's energy mix by producing 22,400 MWe from nuclear power plants by 2032.

- The DAE has sanctioned the building of 10 new PHWRs in ‘fleet mode’ suggesting a plant's completion within five years from the initiation of construction. 

- FBRs have an advantage of generating more nuclear fuel than they consume owing to their capability to convert fertile isotopes into fissile material.

- The Bharatiya Nabhikiya Vidyut Nigam Ltd or BHAVINI, introduced in 2003, was tasked with constructing and operating India’s most sophisticated nuclear reactor, the PFBR.

- When commissioned, India will be only the second country after Russia to operate a commercial FBR.

Exploring the Three Stages of India's Nuclear Energy Program

- First Stage: It involves the ongoing installation of Pressurised Heavy Water Reactors (PHWRs) which employ natural uranium as fuel along with heavy water as a coolant and moderator.

- Second Stage: It targets the installation of FBRs supported by reprocessing plants and plutonium fabrication plants to multiply fissile material.

- Third Stage: Proposed at this stage is an Advanced Heavy Water Reactor (AHWR) for achieving Uranium-233 (U233) by irradiating thorium in PHWRs and FBRs, thereby initiating a Thorium and Uranium Cycle.

- The fusion of power reactors from all three stages will contribute significantly towards securing long-term energy for the country.

Challenges and Way Forward

- For commercial utilisation of thorium significantly, ample supplies of either Uranium-233 (U233) or Plutonium-239 (Pu239) are essential.

- The advancements on the FBR provide a clearer pathway towards the third phase of the nuclear energy program, bringing closer to a future of sustainable and secure energy for the country.