Focussing on small and modular nuclear reactors

As part of India’s long-term push towards nuclear and renewable energy, there has been a lot of focus on small modular nuclear reactors (SMRs). A key highlight of the Indian Union Budget 2025-26 was the launch of a Nuclear Energy Mission, which is focused on research and development of SMRs.

The International Atomic Energy Agency (IAEA) explains on its website nuclear power provides 10% of the world’s electricity, but to stem climate change, far greater amounts of clean and reliable energy are needed. SMRs are advanced nuclear reactors that have a power capacity of up to 300 MW(e) per unit, which is about one-third of the generating capacity of traditional nuclear power reactors. SMRs, which can produce a large amount of low-carbon electricity, are small – physically a fraction of the size of a conventional nuclear power reactor; modular – making it possible for systems and components to be factory-assembled and transported as a unit to a location for installation; reactors – harnessing nuclear fission to generate heat to produce energy.

Many of the benefits of SMRs, as the IAEA website details, are inherently linked to the nature of their design. Given their smaller footprint, SMRs can be sited on locations not suitable for larger nuclear power plants. Prefabricated units can be manufactured, shipped and installed on site, making them more affordable to build than large power reactors, which are often custom designed for a particular location, sometimes leading to construction delays. SMRs offer savings in cost and construction time and can be deployed incrementally to match increasing energy demand. In areas lacking sufficient lines of transmission and grid capacity, SMRs can be installed into an existing grid or remotely off-grid, as a function of its smaller electrical output, providing low-carbon power for industry and the population.

In comparison to existing reactors, proposed SMR designs are generally simpler, and the safety concept often relies more on passive systems and inherent safety characteristics of the reactor, such as low power and operating pressure. This means that in such cases no human intervention or external power or force is required to shut down systems, because passive systems rely on physical phenomena, such as natural circulation, convection, gravity and self-pressurization. These increased safety margins, in some cases, eliminate or significantly lower the potential for unsafe releases of radioactivity to the environment and the public in case of an accident. SMRs also have reduced fuel requirements. Power plants based on SMRs may require less frequent refuelling, every 3 to 7 years, in comparison to between 1 and 2 years for conventional plants. Some SMRs are designed to operate for up to 30 years without refuelling.

A recent legislation passed in the Indian parliament, according to a Press Information Bureau (PIB) media release, reflects the government’s effort to modernize the laws governing the nuclear sector. The legislation permits private companies to participate in India’s nuclear sector, enabling them to undertake plant operations, power generation, equipment manufacturing, and selected activities. In addition, all activities that involve radiation exposure must obtain prior safety authorisation from the regulatory authority.

India’s growing energy demands and clean energy commitments make a strong case for expanding nuclear capacity, as per the PIB release. Round-the-clock electricity is vital for emerging needs such as data centres and advanced industries, yet existing laws do not provide the flexibility or speed required for such growth. To meet the national target of 100 GW nuclear capacity by 2047 and advance long-term decarbonisation by 2070, a modern legal framework is essential, which enables wider participation, leverages indigenous resources, and integrates innovation with safety.

The PIB release adds that India’s nuclear energy programme has maintained a steady role in the country’s electricity mix and is now poised for significant expansion. Nuclear power has consistently accounted for around 3% of total electricity generation, with a share of 3.1% in 2024–25 and the present nuclear capacity stands at 8.78 GW. The country currently operates 24 reactors across seven locations. There is also a planned expansion. With the indigenous 700 MW and 1000 MW reactors being developed through international cooperation, the capacity is projected to rise to 22.38 GW by 2031–32.