New Delhi: India has the largest thorium reserves in the world and there is a ray of hope for greater exploitation of this resource with the first thorium-based nuclear plant “Bhavni” being set up at Kalpakkam in Tamil Nadu, Minister of State for Atomic Energy Jitendra Singh had informed Parliament earlier this year.
“It is going to be entirely indigenous and the first-of-its-kind,” the minister said.
The experimental thorium plant “Kamini” already exists in Kalpakkam.
Thorium is a radioactive metal and the Kerala coastline is estimated to have two lakh tonnes of such deposits. The state’s power utility has sought permission from the Centre to set up a thorium-based nuclear power plant on land at an NTPC unit near the Chavara coast at Kayamkulam.
Indian scientists have been working since the 1950s to develop technology for using thorium as a fuel for generating power. The need for cleaner fuel to generate power added to the need for this quest.
Dutch scientists are also working on the technology as the world seeks to find ways to fight climate change with a switch to clean energy. China, too, has pledged to spend $3.3bn to develop reactors that could eventually run on thorium.
Proponents of thorium say it promises carbon-free power with less dangerous waste, lower risk of meltdowns and a much harder route to weaponisation than conventional nuclear waste.
However, rapid advances in renewables, a costly development path and doubts over how safe and clean future nuclear plants will actually be, are as seen as going against the use of thorium as a fuel for power plants, according to some scientists.
Thorium will have to compete with solar and wind energy projects which are moving at a faster pace on the back of quick technological advances and are considered much safer than nuclear power.
Thorium, despite being found in greater abundance lags behind use of uranium as it does not have any fissile content. It has to be converted into uranium-233 first for use in a nuclear reactor.
The problem is Thorium does not spontaneously undergo fission to release energy that can generate electricity. To turn it into nuclear fuel, it needs to be combined with a fissile material like plutonium, which releases neutrons as it undergoes fission. These are captured by thorium atoms, converting them into a fissile isotope of uranium called U233. An isotype is a variant of an element with a different number of neutrons.
Considering the country’s vast thorium resources, the long-term nuclear energy policy of India has been focused on utilisation of thorium for which a three-stage nuclear power program was drafted in the 1950s.
An important element in this roadmap includes demonstrating the use of thorium on an industrial scale in Advanced Heavy Water Reactors (AHWR). This has the benefit of adopting many of the mature technologies currently in use in existing reactor systems, and will provide a platform for developing advanced thorium cycle technologies.