‘Future powered by thorium’: India has the largest thorium reserve and an impressive nuclear power plan

India has one of the largest share of global thorium reserves at about 25 per cent of the known thorium reserves – and that’s rather great news for the country’s nuclear power ambitions. India wants a future powered by thorium and the Kalpakkam Nuclear Complex is just the beginning of the plan. 

The indigenously designed and built Prototype Fast Breeder Reactor (PFBR) at Kalpakkam attained first criticality – the point at which a sustained and controlled nuclear fission chain reaction begins – on April 6. The 500 MWe (MegaWatt electrical) reactor, PFBR, was built by Bharatiya Nabhikiya Vidyut Nigam Limited (BHAVINI) at the Kalpakkam Nuclear Complex.

The reactor makes more fuel than it burns and at 500 MWe, it will be able to power 4-5 lakh average Indian homes simultaneously. It will undergo a series of low-power experiments before it is connected to a critical grid. 

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This is all part of India’s nuclear power programme, and it is where thorium comes in. 

To begin with, India’s impressive nuclear power programme involves three stages:

Stage 1: Natural uranium is used as fuel in Pressurised Heavy Water Reactors (PHWRs) to generate power, and the spent fuel from these reactors produces plutonium – the primary input for the next stage.

Stage 2: The plutonium obtained from the first stage is used as fuel in Fast Breeder Reactors, which generate more fuel than they consume. We are at this stage now. These reactors will now be used to breed Uranium-233 from thorium, leading to the next stage. 

Stage 3: At this stage, India will harness its massive thorium reserves. Thorium, in short, holds the answer to India’s long-term energy security. 

So, what is thorium exactly?

Thorium, discovered in 1828 by Swedish chemist Jons Jakob Berzelius, gets its name from the Norse god of thunder, Thor. thorium is found in small amounts in most rocks and soil – far more abundant than uranium. In its pure form, thorium is in a silvery white metal. 

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Thorium in itself is not fissile – able to undergo nuclear fission – and hence is not used directly in thermal neutron reactor. However, it is fertile and upon absorbing a neutron will transmute to Uranium-233, which is an excellent fissile material, said the World Nuclear Association. 

However, as opposed to India’s limited – only 1-2% – uranium reserves, thorium is in abundance in the country. Uranium is mostly imported. The push for thorium is, hence, inevitable. 

The association expects it to be 15-20 years till India is using thorium energy to any extent.