Small modular reactors explained: why Amazon wants 12 of them, and where India's plans stand

What is a small modular reactor?

A nuclear reactor small enough to be built mostly in a factory and added in units.

The International Atomic Energy Agency describes small modular reactors, or SMRs, as producing up to 300 megawatts of electricity per module. A conventional large reactor produces 1,000 MW or more. The idea is that smaller units can be made on assembly lines, shipped to a site and switched on in stages, cutting the long construction times and cost overruns that have dogged big nuclear plants.

They do the same basic job as any reactor: splitting uranium atoms to make heat, which drives turbines. Many designs also lean on passive safety, cooling themselves without pumps or operators in an emergency, which supporters say allows a much smaller safety zone around the plant.

What has Amazon announced?

A 960 MW plant made of 12 reactors on the site of a demolished coal plant near Terre Haute, Indiana.

The plant would use the Xe-100, a design by the American company X-energy, with each unit producing about 80 MW. The utility American Electric Power would run it and Amazon would be its first customer. The electricity would go into the public grid and, Amazon says, also serve its data centres.

It is the second deal between the two companies and three times the size of the first, announced in 2024, when Amazon also led a $700 million funding round in X-energy. They have set a goal of 5 gigawatts of new nuclear capacity in the US by 2039. Amazon has not said what the Indiana plant will cost.

Why are tech companies doing this?

Because artificial intelligence runs on electricity, around the clock. Data centres need steady power that does not depend on the sun or the wind, and companies have promised to cut their carbon emissions. Nuclear power offers both. Old coal sites are attractive because they already have grid connections, cooling water and land zoned for power generation.

What is India planning?

At least five home-grown SMRs by 2033, as part of a push to 100 GW of nuclear power by 2047.

The Union Budget for 2025-26 announced a Nuclear Energy Mission with ₹20,000 crore for research and development of SMRs. In August, Minister of State for Atomic Energy Jitendra Singh told the Lok Sabha that India planned to develop and operationalise at least five indigenous SMRs by 2033. Large 700 MW reactors would go to new sites, he said, while SMRs would be used at existing industrial sites, to replace retiring fossil-fuel plants, to give energy-heavy industries their own power and to reach remote areas.

The Bhabha Atomic Research Centre is working on three designs.

Can private companies build them?

Now they can. The Atomic Energy Act of 1962 kept nuclear power in government hands. The SHANTI Act of 2025, short for Sustainable Harnessing and Advancement of Nuclear Energy for Transforming India, allows public and private entities to take part, and gives the Atomic Energy Regulatory Board statutory status. Several large industrial groups, including Tata Power, JSW, Jindal Steel and Reliance Industries, have been reported as interested in hosting reactors at their sites.

What is the catch?

Cost, and the lack of a proven commercial model. Few SMRs are working anywhere, and X-energy has not yet broken ground on its first plant, at a Dow Chemical site in Texas, which is still awaiting a construction permit. Analysts at the Manohar Parrikar Institute for Defence Studies and Analyses noted that nuclear power cost about $110 per megawatt-hour in 2023, against about $55 for solar and $40 for wind.

Supporters argue that factory production will bring costs down once dozens of units are built. That is the bet Amazon is making in Indiana, and the one India is making with its own designs: that small reactors can become a product, not a series of one-off megaprojects.