What are Molten Salt Reactors?

The Government of India has stated that Molten Salt Reactors (MSRs) are being considered as a potential technology for thorium utilisation in India’s nuclear energy programme. The information was provided in a written reply in the Lok Sabha on March 11, 2026.

According to the government, the Molten Salt Breeder Reactor (MSBR)—a variant of MSR using thorium-based fuel—is envisaged for deployment in the third stage of India’s nuclear power programme. These reactors operate at near atmospheric pressure, which enhances safety compared to conventional reactors.

However, the government noted that the technology is not yet fully mature, and its economic viability can only be assessed after limited-scale demonstration.

What are Molten Salt Reactors?

As per the International Atomic Energy Agency (IAEA), MSRs are nuclear fission reactors in which either the fuel or the coolant, or both, consist of molten salt.

Molten salts are compounds that liquefy at high temperatures and can store large amounts of thermal energy at atmospheric pressure. When used as fuel, the molten salt is mixed with fissile material, a substance capable of undergoing Nuclear Fission—a process in which an atomic nucleus splits to release energy.

Potential Advantages of MSRs

• Lower carbon emissions, helping decarbonize industrial processes
• Ability to produce large amounts of efficient and cost-effective electricity
• Smaller high-level nuclear waste footprint
• Passive safety features, improving reactor safety
• Sustainable fuel cycle options, particularly with thorium

Sources: PIB & IAEA