Context: Recently, China has successfully refuelled a working 2MW Thorium-fuelled molten salt reactor without causing a shutdown.
Relevance of the Topic: Prelims & Mains: Thorium fuelled Nuclear reactors; Advantages of Thorium reactors over Uranium reactors.
Thorium Reactor in China
- China has developed a small, 2MW experimental Thorium Nuclear Reactor in the Gobi Desert, near the Mongolian border. It is operational from 2024.
- China is working towards developing a 10 MW Thorium Nuclear Reactor for commercial use by 2030.
- China’s efforts have put it at the forefront of both thorium-based fuel breeding and molten-salt reactors.
Thorium based Nuclear Reactors
- Thorium (Th-232) is a fertile material that has to be converted to fissile material Uranium 233. The naturally occurring isotope Th-232 cannot be fissioned, but when irradiated in a reactor it absorbs neutrons and forms uranium-233, a fissile material that generates heat.
- Coolant: Molten salt. China’s reactors use fluoride-based salts, which melt into a colourless, transparent liquid when heated to about 450 ºC. The salt acts as a coolant to transport heat from the reactor core.
- Rather than solid fuel rods, molten-salt reactors use the liquid salt as a substrate for the fuel, such as thorium, to be directly dissolved into the core.
- Compared to light water reactors in conventional nuclear power plants, molten salt reactors work at significantly higher temperatures. The result is that it can generate electricity much more efficiently.
Thorium reactors offer multiple Advantages:
As the world confronts the twin challenges of climate change and energy security, Thorium is making a comeback.
- Less radioactive waste (burning thorium does not create plutonium, a highly toxic chemical element)
- Cheaper alternative to Uranium and More fuel-efficiency
- Far safer (because the fuel is already dissolved in liquid and they operate at lower pressures than do conventional nuclear reactors, which reduces the risk of explosive meltdowns)
- Lower risk of nuclear weapons proliferation (its waste products are less weapons-grade than Uranium)
- Does not need to be built near watercourses, since the molten salts serve as a coolant. (Conventional uranium power plants that need huge amounts of water to cool their reactors).
India and its plan to use Thorium Reactors
- India has the world’s largest reserves of thorium — a million tonnes — particularly in its monazite-rich coastal sands.
- As per the three-stage nuclear programme envisioned by nuclear scientist Dr Homi Bhabha, the country would use thorium reactors in the third stage. However, India has only commenced its second stage of nuclear programme in 2024.
Also Read: Three-stage Nuclear Program of India