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Expert Explains | How thorium can power India’s 100 GWe by 2047 mission

India holds the world’s largest thorium reserves, and thorium use not only offers energy independence but also virtually eliminates proliferation risk

Narora Atomic Power Plant (Wikimedia Commons)

5 min readNew DelhiMar 16, 2026 04:54 PM IST First published on: Mar 5, 2026 at 07:38 AM IST

The SHANTI Act 2025 represents a watershed moment for India’s atomic energy programme. It opens the doors of nuclear energy to the public and private sectors, academia and industry alike, fostering an ecosystem that responds to India’s needs and opportunities in this field. There is visible enthusiasm among stakeholders. While legislation is an enabler, a conducive regulatory framework, free from monopolistic tendencies, is equally essential to realise our development goals.

The growth of our nuclear generation capacity currently depends heavily on imported uranium. Domestic uranium ores are lean and costly to extract, though this does provide some insulation against supply disruptions. The ‘100 GWe by the year 2047’ nuclear energy mission announced by the Government consists largely of thermal reactors, which would require around 18,000–20,000 tonnes of mined uranium annually — roughly a third of current global production.

By the time India reaches 100 GWe, global nuclear generation capacity is expected to grow from around 380 GWe today to around 1,400 GWe. At that scale, known global uranium resources of around 8 million tonnes could sustain the fleet in once-through mode for only about three decades.

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Two conclusions follow: uranium use in once-through mode is not sustainable, and securing our share of global uranium supply will become progressively more difficult.

Thorium recycling as an alternative

Nuclear capacity will need to grow well beyond 2047. Energy demand is perpetual, and fission must play its role, at least until fusion energy arrives at the requisite scale. The solution to uranium supply constraints in once-through mode is nuclear recycling, which increases the energy potential of nuclear fuel 50- to 100-fold. Yet, with a few notable exceptions — France, India, and Russia — most countries have not adopted recycling, citing fears of fissile material diversion for weapons proliferation.

Shifting to thorium recycling changes this situation: India holds the world’s largest thorium reserves, and thorium use not only offers energy independence but also virtually eliminates proliferation risk. Resolving the remaining challenges of thorium utilisation is therefore urgent and demands a large, multidisciplinary effort with significant scope for innovation.

FBRs and HALEUs as pathways

India’s three-stage nuclear power programme, designed to leverage thorium resources, envisages fast breeder reactors (FBRs) as the stage beyond thermal reactors. The first 500 MWe Prototype Fast Breeder Reactor is almost ready. Beyond this, metal-fuelled FBRs with associated fuel recycling technology must also be developed to achieve the short doubling times needed to support rapid capacity growth. The phase in which fast reactor capacity grows in step with economic demand is, realistically, still about three decades away.

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The principal purpose of FBRs is to irradiate thorium at scale and produce the uranium-233 needed for the third stage. While that is delayed, the 100 GWe mission — fuelled largely by imported uranium — is driving Pressurised Heavy Water Reactor (PHWR) capacity well beyond the 10 GWe previously envisaged. This creates a valuable opportunity: irradiating thorium in PHWRs can advance uranium-233 production and accelerate deployment of third-stage Thorium Molten Salt Reactor (TMSR)-based Small Modular Reactors (SMRs). Doing so would recover some lost time and ease the inevitable slowdown in nuclear power growth between the first and second stages.

Large-scale thorium irradiation can, in fact, be carried out in PHWRs with no significant design changes by using thorium in combination with HALEU (high-assay low-enriched uranium) as fuel. This approach offers additional benefits in economics, safety, and, as noted above, proliferation resistance. Most significantly, burnup levels comparable to light water reactors become achievable, leading to considerably less spent fuel and lower back-end costs.

Qualifying such HALEU–thorium fuel requires accelerated irradiation testing and demonstration in actual PHWRs. India currently lacks facilities for accelerated irradiation testing, but existing international cooperation agreements can be leveraged — preferably as genuine partnerships rather than simple vendor–buyer arrangements. On fuel supply, India already imports both natural and enriched uranium; the HALEU supply chain is evolving rapidly, driven by demand from numerous next-generation reactor programmes worldwide.

Alongside the TMSR, SMRs capable of producing low-cost green hydrogen via direct thermochemical routes must also be developed. Both these systems, together with metal-fuelled fast reactors, could share a common back-end technology: the pyrochemical nuclear recycling process. Irradiated HALEU–thorium fuel could likewise be recycled using this approach. These are challenging developments, but achievable with concerted effort. China has already taken the lead. This should be India’s priority focus for SMR development — as highlighted in the 2025–26 budget.

One hopes that the broader ecosystem envisaged in the SHANTI Act will soon take shape, and that efforts towards India’s energy independence will gain the momentum they deserve.

Anil Kakodkar is the former chairman of the Atomic Energy Commission and now Chancellor of the Homi Bhabha National Institute and Chairman of the Rajiv Gandhi Science & Technology Commission.