PIB TrackerThe three-stage nuclear plan enters its second stage
A PIB backgrounder sets out the fuel-cycle logic behind India's programme: 24 reactors at 8.78 GW today, the Kalpakkam breeder critical in April 2026, and 100 GW targeted by 2047.
What happened
- India operates 24 nuclear reactors totalling 8.78 GW; nine more of 7.5 GW are under construction.
- The Prototype Fast Breeder Reactor at Kalpakkam attained first criticality in April 2026, opening the second stage.
- Ten indigenous PHWRs in fleet mode and pre-project work on two 500 MW Fast Breeder Reactors have been approved.
- ₹20,000 crore was allocated in Union Budget 2025-26 for indigenous Small Modular Reactors.
- The Nuclear Energy Mission targets 100 GW by 2047, with at least five indigenous SMRs by 2033.
For Prelims
- Three-stage programme: proposed by Homi J. Bhabha in 1954 — PHWRs on natural uranium, Fast Breeder Reactors on plutonium, then thorium reactors on uranium-233.
- Fissile and fertile: fissile fuel sustains the chain reaction directly; fertile thorium-232 must absorb a neutron to become fissile U-233.
- Thorium: found mainly in the coastal sands of Kerala, Tamil Nadu, Andhra Pradesh, Odisha, West Bengal and Jharkhand.
- PHWR: India's mainstay reactor, running on natural uranium and needing no enrichment; India also operates BWRs and PWRs.
- PFBR: designed by IGCAR with nearly 90 per cent indigenous manufacture; first criticality at Kalpakkam in April 2026.
- Breeder reactor: one that produces more fissile material than it consumes while generating electricity.
- Small Modular Reactors: up to 300 MWe; India is building the 220 MWe BSMR-200 with BARC and NPCIL, the 55 MWe SMR-55 and a high-temperature gas-cooled reactor for hydrogen.
- Policy frame: the SHANTI Act, 2025 and the Nuclear Energy Mission (2025-26), targeting 100 GW by 2047 with greater private participation.
For UPSC: The reference item for the closed fuel cycle, the thorium strategy and India's reactor classification, now anchored to a dated milestone. Use it on energy security, indigenisation of strategic technology and the place of baseload power in a renewables-heavy grid.
What it is NOT: The Kalpakkam criticality does not mean India is running on thorium — the second stage breeds the uranium-233 that a third stage would use, and no third-stage reactor is operating.
For Mains
Syllabus: GS3.12 · GS3.13 · Linkage L1
Anchor
The three-stage design was never principally about electricity; it was a way of converting a low-grade uranium endowment and a history of fuel embargoes into a thorium strategy.
Substantiation (data)
24 reactors at 8.78 GW, nine more of 7.5 GW under construction, ten PHWRs cleared in fleet mode, ₹20,000 crore for SMRs and 100 GW targeted by 2047.
Exemplification
IGCAR achieved close to 90 per cent domestic manufacture of the PFBR's equipment and systems — indigenisation measured on a reactor rather than on a policy document.
Problematisation
8.78 GW today against 100 GW by 2047 leaves the arithmetic to nine reactors under construction, ten approved, and a reactor class — the SMR — that India has not yet built.
Way-forward
The backgrounder's own weight falls on Small Modular Reactors, five of them indigenous by 2033, as the way to add capacity without repeating large-reactor construction timelines.
Position
Stage two matters less as generation than as fuel: a reactor that makes more fissile material than it burns is the only route India has to its own thorium.
Deploys into: Indigenisation of technology + energy and strategic technology (GS3.12, GS3.13) · the closed fuel cycle, the thorium route and small modular reactors in India's energy mix.
Department of Atomic Energy · 2026-08-28 · PRID 2304034 · PIB source ↗