Why in the News?

Thorium-based nuclear power is gaining attention again as India expands its Pressurized Heavy-Water Reactor (PHWRs) using imported uranium, which allows faster production of fissile material needed for thorium use. Earlier, limited domestic uranium kept reactor capacity low and delayed the thorium programme. With a target of 100 GWe nuclear capacity, largely through PHWRs, India can now produce enough U-233, making thorium reactors practically feasible. This reflects a clear shift from long-term planning to real implementation, strengthening energy independence.

How Does India’s Three-Stage Nuclear Programme Enable Thorium Use?

1. Three-stage framework: Structures India’s nuclear strategy around uranium, plutonium, and thorium to overcome resource asymmetry.
2. Stage One (PHWRs): Uses natural uranium to generate electricity and produce plutonium as a by-product.
3. Stage Two (Fast Breeder Reactors): Utilises plutonium to generate power and multiply fissile material.
4. Stage Three (Thorium reactors): Converts thorium into U-233, enabling long-term clean energy production.
5. Strategic outcome: Ensures sustained energy security using domestically abundant thorium reserves.

Why Is Scaling Up PHWR Capacity Critical for Thorium Transition?

1. Irradiation capacity: Enables production of U-233 by irradiating thorium in sufficient quantities.
2. Earlier constraint: Limited domestic uranium restricted reactor scale when the programme was conceptualised.
3. Current shift: Access to international uranium markets removes fuel bottlenecks.
4. Capacity expansion: Nuclear roadmap targets 100 GWe, with PHWRs forming the backbone.
5. Transition acceleration: Large-scale PHWR deployment shortens the timeline for thorium-based power.

What Role Do Advanced PHWR Designs Play in Energy Independence?

1. Technological evolution: Enables use of thorium in PHWRs through advanced fuel cycles.
2. Fuel innovation: Facilitates blending of thorium with HALEU (High-Assay Low-Enriched Uranium).
3. Efficiency gains: Improves fissile breeding and fuel utilisation.
4. Strategic benefit: Reduces reliance on fast breeder reactors alone for thorium transition.
5. System-wide impact: Enhances safety, economic viability, and fuel security.

How Feasible Is Rapid PHWR Capacity Expansion in India?

1. Scale requirement: Achieving 50-75 GWe requires addition of approximately 3 GWe annually.
2. Infrastructure implication: Construction of five to eight reactors per year.
3. Capital intensity: Demands significant financial mobilisation for reactors, fuel cycle, and back-end facilities.
4. Institutional expansion: Requires entry of multiple public and private players beyond existing structures.
5. Implementation role: Positions NPCIL as technology provider, capacity builder, and programme integrator.

What Is the Case for Imported Light-Water Reactor (LWR)-Based Nuclear Projects?

1. Complementarity: Supplements indigenous PHWR capacity during rapid scale-up.
2. Fuel efficiency: Higher energy output per unit of enriched fuel.
3. Economic condition: Viability depends on cost competitiveness and fuel cycle consistency.
4. Strategic balance: Does not replace indigenous systems but supports capacity growth.
5. Policy approach: Prioritises futuristic technologies while leveraging imported reactors pragmatically.

How Does Fuel Cost Comparison Strengthen the PHWR Case?

1. LWR fuel demand: A 1,000 MWe LWR requires ~25 tonnes of enriched fuel annually at 80% PLF.
2. Cost implication: At $1.76 million per tonne, fuel costs translate to ~₹350 crore/year (±₹80 crore).
3. PHWR advantage: Requires lower enriched uranium input due to higher efficiency in mined uranium use.
4. Hybrid fuel strategy: Using small amounts of enriched uranium with thorium in PHWRs reduces overall cost.
5. Outcome: Positions PHWRs as economically superior for clean power expansion.

Conclusion

India’s nuclear energy pathway is entering a decisive phase where scale, fuel flexibility, and technological maturity converge. Expansion of PHWR capacity using imported uranium removes historical constraints on thorium utilisation, enabling faster production of U-233 and improving the feasibility of thorium-based reactors. Combined with advanced fuel designs and selective use of imported LWRs, this strategy strengthens India’s long-term energy independence while ensuring cost efficiency and system resilience.

PYQ Relevance

[UPSC 2018] With growing energy needs should India keep on expanding its nuclear energy programme? Discuss the facts and fears associated with nuclear energy?

Linkage: This question tests understanding of India’s long-term energy security choices amid rising power demand and clean energy transition. The article shows how scaling up PHWRs and advancing the thorium fuel cycle addresses energy security.

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