PFBR Achieves Criticality; Godrej Enterprises Delivers Key Reactor Components

Indigenous precision engineering powers milestone in India’s three-stage nuclear programme and long-term energy security roadmap

Mumbai: India’s civil nuclear programme has reached a major milestone with the Prototype Fast Breeder Reactor (PFBR) at Kalpakkam achieving criticality, advancing the country into the next phase of its three-stage nuclear energy roadmap focused on fuel efficiency and long-term energy security.

The milestone also underscores the role of domestic engineering capabilities, with the Precision Engineering business of Godrej Enterprises Group manufacturing and supplying critical reactor components, including the Large Rotating Plug (LRP), Small Rotating Plug (SRP), and the Sodium Pump Shaft.

These components represent a combination of large-scale fabrication and high-precision engineering. The rotating plugs—measuring up to 8 metres in diameter and weighing nearly 120 tonnes—are designed for 360-degree rotation with exact alignment to enable precise fuel insertion into the reactor core. The 10-metre sodium pump shaft operates at over 500 RPM in a liquid sodium environment, requiring stringent control over balance, material integrity, and operational reliability.

The systems were designed and manufactured indigenously without prior domestic reference, marking a first-of-its-kind, first-time-right achievement in India’s nuclear engineering landscape.

Execution involved overcoming complex engineering challenges, including the development of specialised bearing systems, friction-controlled surface treatments, and gear mechanisms capable of operating under stringent and seismic conditions. These solutions were developed entirely in-house, highlighting India’s growing capability in advanced manufacturing for strategic sectors.

The components were supplied to Bharatiya Nabhikiya Vidyut Nigam Limited, a Government of India enterprise responsible for fast breeder reactor projects.

The PFBR’s criticality marks the culmination of over two decades of development and is a crucial step in India’s three-stage nuclear programme. Fast breeder reactors enable a closed fuel cycle by utilising plutonium derived from Pressurised Heavy Water Reactors (PHWRs) while generating more fissile material, thereby supporting long-term sustainability. With an estimated 846,000 tonnes of thorium reserves, this stage is central to unlocking India’s potential for low-carbon, self-reliant energy.

India currently operates 19 PHWRs, with 10 additional 700 MWe units sanctioned, strengthening the upstream supply for fast breeder reactors in the coming years.

Godrej Enterprises Group said it continues to contribute to India’s strategic and industrial capabilities through advanced engineering solutions, supporting critical infrastructure across sectors aligned with national development priorities.