Understanding small modular reactors, a new type of nuclear power plant designed to supply energy for AI's increasing demand.

As the demand for electricity in the U.S. continues to grow and tech companies expand large-scale data centers to support artificial intelligence, the challenge of supplying sufficient energy becomes more urgent. In 2022, global large-scale data centers consumed approximately 460 terawatt-hours of electricity, according to the International Energy Agency, with projections indicating continued growth in the coming years.

One proposed solution is nuclear power, including traditional large-scale reactors, reactivated older plants, and innovative smaller designs currently under development. Among these, small modular reactors (SMRs) have garnered attention for their potential role in powering AI infrastructure.

The International Atomic Energy Agency notes that around 70 SMR designs are being explored worldwide. These reactors could serve a variety of applications, from small communities and remote locations to military installations and even ships or spacecraft. Advocates highlight their ability to provide stable electricity without greenhouse gas emissions and their flexibility to be located near demand centers, reducing dependence on extensive grid infrastructure. However, commercial deployment is still several years away, with demonstration projects expected before 2030 and potential commercial operations by the mid-2030s. A long-term strategy for managing radioactive waste from SMRs is not yet in place.

How Small Modular Reactors Work

Nuclear reactors generally fall into three categories based on size. Conventional large reactors, built on permanent sites with cores up to 10 meters tall, generate over 1,000 megawattsenough to power hundreds of thousands of homes. Microreactors, in contrast, are compact enough to fit on a truck trailer, producing less than 20 megawatts on a site roughly the size of a football field.

SMRs occupy the middle ground. Their cores are about 3 meters wide and 6 meters tall, and the full facility covers around 50 acres, capable of generating up to 300 megawatts. Their modular design allows components to be manufactured in factories and transported to sites for assembly by truck, rail, or ship.

All SMRs generate heat by splitting heavy atoms, which is captured by coolants such as water, molten salt, or liquid metal to produce steam that drives turbines. Advanced safety systems, including passive mechanisms relying on natural principles like gravity, are built in to prevent accidents and minimize radiation risk. Their smaller size and reduced nuclear material content lower the potential hazards compared to conventional reactors.

Applications and Advantages

SMRs are particularly suited for remote regions or areas lacking robust power grids. Their compact footprint allows installation in locations unsuitable for larger plants and enables rapid construction, often within two to three years, compared to a decade or more for conventional reactors. They are also adaptable for industrial purposes, such as powering desalination plants, mining operations, or university campuses, providing both electricity and heat efficiently.

Fuel for SMRs varies from 5% to 20% uranium-235, higher than traditional reactors but far below weapons-grade levels. This "high-assay low-enriched uranium" allows longer operation between refueling and reduces the resulting radioactive waste volume. The U.S. Department of Energy is supporting domestic production of this fuel, with contracts awarded to Centrus Energy to supply demonstration projects and development reactors.

Challenges Ahead

Before widespread deployment, several technical and regulatory issues must be addressed. These include staffing requirements, safety standards, and safe handling and transport of new forms of radioactive waste. The lack of a permanent storage solution for nuclear waste in the U.S. remains a significant hurdle.

Despite these challenges, SMRs offer a promising, flexible energy solution capable of meeting specialized electricity and heat demands, particularly for AI data centers, remote installations, and educational institutions, while minimizing carbon emissions.

Author: Harper Simmons