India's Three-Stage Nuclear Programme Advances with FBR Criticality at Kalpakkam

Indian Express - Explained · 21 Apr 2026 · 2 min read
Prelims · Science and technology Mains · GS3 Science and technology High relevance

India's first indigenous Fast Breeder Reactor (FBR) at Kalpakkam achieving criticality marks a milestone in the second stage of India's three-stage nuclear programme, enhancing energy security through plutonium breeding and thorium utilization.

Key points

Fast Breeder Reactor (FBR) at Kalpakkam has achieved criticality, a key milestone in India's three-stage nuclear programme aimed at achieving energy independence through thorium utilization.

Three-Stage Nuclear Programme consists of PHWRs (Stage 1), FBRs (Stage 2), and thorium-based reactors (Stage 3), designed to exploit India's limited uranium but abundant thorium reserves.

Pressurised Heavy Water Reactors (PHWRs) will continue to anchor India's nuclear energy production until FBR technology matures, as they produce plutonium required for FBRs.

NPCIL plans to expand nuclear capacity to 22 GWe by 2031-32 and 54 GWe by 2047, with PHWRs remaining central to indigenous nuclear power development.

[GS3-Economy] The deregulation of India's nuclear sector and NPCIL's 'motherly role' in fostering private participation could accelerate capacity addition and technology transfer.

Thorium Utilization is critical for India's long-term energy security, with FBRs converting Thorium-232 to Uranium-233, the fuel for advanced reactors in Stage 3.

India's focus on PHWRs and FBRs stems from historical technology denial regimes that restricted access to enriched uranium, necessitating indigenous solutions.

Way Forward: India should accelerate FBR commercialization, enhance public-private partnerships in nuclear technology, and invest in thorium fuel cycle R&D to achieve energy independence.

Key terms

Pressurised Heavy Water Reactor (PHWR)

A nuclear reactor that uses natural uranium as fuel and heavy water as moderator. For UPSC, PHWRs are significant as they form Stage 1 of India's nuclear programme and produce plutonium essential for FBRs, while avoiding dependence on enriched uranium.

Nuclear Power Corporation of India Limited (NPCIL)

A public sector enterprise under DAE responsible for nuclear power generation. Its role in technology development, capacity expansion to 54 GWe by 2047, and fostering private participation makes it institutionally significant for GS3 (Economy) and GS2 (Governance).

Fast Breeder Reactor (FBR)

A nuclear reactor that generates more fissile material than it consumes by converting fertile material (Thorium-232) into fissile material (Uranium-233). For UPSC, this is significant as it represents Stage 2 of India's nuclear programme, crucial for utilizing thorium reserves and achieving energy security.

Three-Stage Nuclear Programme

India's indigenous nuclear power strategy comprising PHWRs (natural uranium), FBRs (plutonium), and thorium-based reactors. This is vital for UPSC as it addresses India's unique resource constraints and energy security needs through technological self-reliance.