0.1 India’s core nuclear constraint

0.1.1 India’s nuclear strategy is shaped by a basic resource constraint.
0.1.2 The country has limited uranium, which is required to run most nuclear reactors today.
0.1.3 At the same time, India has vast reserves of thorium, which cannot directly generate power.
0.1.4 This mismatch explains why India designed a long-term, staged nuclear programme.

0.2 The three-stage nuclear programme

0.2.1 In Stage One, PHWRs use uranium to produce electricity.
0.2.2 During this process, plutonium is produced as a by-product.
0.2.3 In Stage Two, this plutonium is used in fast reactors to multiply nuclear fuel.
0.2.4 In Stage Three, thorium is converted into uranium-233, which can be used as nuclear fuel.
0.2.5 The final objective is long-term energy security through thorium.

0.3 Why thorium is linked to energy independence

0.3.1 Thorium-based nuclear power allows India to rely on domestic resources.
0.3.2 It reduces long-term dependence on imported uranium.
0.3.3 This makes thorium central to achieving sustained energy independence, not just short-term power generation.

0.4 Why progress towards thorium was slow earlier

0.4.1 When the three-stage programme was formulated, domestic uranium availability was modest.
0.4.2 There was insufficient reactor capacity to irradiate thorium and produce uranium-233 at scale.
0.4.3 As a result, progress towards thorium depended heavily on fast reactors, slowing the transition.

0.5 What has changed in the current phase

0.5.1 India can now access uranium from international markets.
0.5.2 Thermal reactor capacity, especially PHWRs, is expanding.
0.5.3 The Nuclear Energy Mission targets 100 GWe of nuclear capacity, with PHWRs forming the bulk.
0.5.4 This creates a new opportunity to advance the thorium programme.

0.6 Role of PHWR scale-up in faster thorium transition

0.6.1 Expanded PHWR capacity allows irradiation of thorium within existing reactors.
0.6.2 Thorium can be used alongside advanced fuels such as HALEU.
0.6.3 This enables production of uranium-233 at scale.
0.6.4 PHWRs built for present electricity needs can also support future thorium-based power.

0.7 Economic and cost considerations

0.7.1 PHWRs are more efficient in terms of mined uranium requirement.
0.7.2 Fuel fabrication and back-end fuel cycle costs are higher with natural uranium due to low burn-up.
0.7.3 These costs reduce with enrichment and thorium-based fuel use.
0.7.4 Fueling PHWRs with HALEU-thorium combinations works out cheaper than using natural uranium alone.

0.8 Central takeaway of the article

0.8.1 Thorium-based nuclear power is essential for India’s long-term energy independence.
0.8.2 The ongoing expansion of PHWR capacity provides a timely opportunity.
0.8.3 Using present reactors strategically can accelerate India’s transition to a thorium-driven nuclear future.