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India's fast breeder reactor hits criticality milestone

Source: thehindu.com

TL;DR

India's prototype fast breeder reactor at Kalpakkam achieved criticality on April 6, 2026.
Current pressurised heavy water reactors use only about 1% of fuel before it becomes unusable.
Fast breeders address fuel inefficiency by sustaining chain reactions more effectively.

The story at a glance

India's prototype fast breeder reactor (PFBR) at Kalpakkam reached criticality on April 6, 2026, marking a key step in its nuclear power program. This milestone involves engineers from India's nuclear sector controlling fuel, neutron access, and temperature to sustain fission chain reactions. It's reported now due to the recent achievement, contrasting with past slow progresses in achieving criticality.

Key points

Most of India's reactors are pressurised heavy water reactors, which are inefficient as only around 1% of fuel undergoes fission before becoming unusable.
Criticality means the reactor's chain reaction sustains itself, with each fission releasing neutrons that trigger at least one more fission.
Engineers achieve criticality by adjusting fuel composition, neutron access to nuclei, and reactor temperature.
This is the first step in reactor operation, not the end goal, despite common misconceptions.
The PFBR at Kalpakkam represents a shift toward fast breeder technology to improve fuel use.

Details and context

India pursues fast breeder reactors to overcome the limitations of its current pressurised heavy water reactors, where fuel waste occurs after minimal fission. Fast breeders aim for better efficiency by design, though the article focuses on the recent criticality milestone rather than full operational details.

Criticality requires precise control: fission splits atomic nuclei, releasing neutrons that must hit nearby nuclei to continue the chain. India's nuclear program has a history of gradual successes in reaching this point, often seen as tedious but essential.

Why it matters

Fast breeder reactors could help India maximize limited uranium resources and boost nuclear power output amid growing energy needs. For policymakers and energy planners, this means potential for more sustainable fission-based electricity without quick fuel depletion. Watch for upcoming steps like full power tests and fuel loading, though timelines remain uncertain.