Small Modular Reactors (SMR): A Promising Technology for Clean Energy

Principia / Blog / Consultancy / Small Modular Reactors (SMR): A Promising Technology for Clean Energy

Small Modular Reactors (SMR): A Promising Technology for Clean Energy

16-01-2025 | Posted by Joaquín Martí

As the world grapples with the pressing issue of climate change, the search for sustainable and reliable energy sources has intensified. One promising technology emerging is small modular reactors (SMRs), advanced nuclear reactors with a power capacity of up to 300 MW(e) per unit, which is about one-third of the generating capacity of traditional reactors. SMRs, which can produce a large amount of low-carbon electricity, are small (physically a fraction of the size of a conventional 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).

SMRs offer several potential advantages over conventional nuclear power plants. Their smaller size allows deployment in remote locations or areas with limited grid capacity. They can be built in factories, reducing construction time and costs. They often have simpler designs, and their safety concept tends to rely more on passive systems and inherent safety characteristics, which can make them safer and more reliable. They can be deployed in a modular fashion, allowing for gradual expansion of power capacity. They typically require less frequent refuelling. And they can be used for a variety of applications apart from baseload electricity generation, like desalination of sea water, district heating, or supplying heat or steam for industrial processes.

More than 80 commercial SMR designs are currently being developed around the world, targeting varied outputs and different applications. The main ones are:

Pressurized water reactors (PWRs), using pressurized water to cool the reactor core and generate steam; they are the most common type of light water reactor, and the most widely used type of SMR.
Boiling water reactors (BWRs), in which the water in the reactor core is allowed to boil, thus generating steam directly.
High-temperature gas-cooled reactors (HTGRs), which use graphite as a moderator and helium as a coolant. They operate at higher temperatures, making them more efficient.
Molten salt reactors (MSRs), using molten salt as both a coolant and a fuel, allowing them to operate at high temperatures and to use different fuels, including thorium and uranium.
Supercritical water-cooled reactors (SCWRs), using water heated above its critical point, which allows them to operate at very high pressures and temperatures.
Other designs in various development stages, such as Small Modular Advanced High Temperature Reactor (smAHTR), Traveling Wave Reactor (TWR), Lead-cooled Fast Reactor (LFR), Very High Temperature Reactor (VHTR), etc.

There are of course challenges and concerns that need to be addressed. These include issues of cost, safety, regulation, and public acceptance. Despite those challenges, both public and private institutions are actively participating in efforts to bring SMR technology to fruition within this decade. Russia’s Akademik Lomonosov, the world’s first floating nuclear power plant that began commercial operation in May 2020, is producing energy from two 35 MW(e) SMRs.

In October 2024 Google ordered six to seven reactors of the MSR type from Kairos Power with a total capacity of 500 MW. Around the same time Amazon.com signed agreements with X-Energy and Northwest Energy on developing HTGR technology to meet surging electricity demand from its data centres. Apart from the United States, other SMRs are under construction or in the licensing stage in Argentina, Canada, China, Russia, and South Korea.

The International Atomic Energy Agency (IAEA) has an explanatory page on this topic. They have also established the Platform on SMRs and their Applications, a one-stop shop for countries to coordinate support related to all aspects of SMR development, deployment, oversight and their electric and non-electric applications, such as use in district heating and desalination systems.

It is clear that SMRs have a significant role to play in the energy transition. With continued development and investment, they have the potential to provide a reliable, clean, and cost-effective source of energy for years to come. Principia has worked on many types of nuclear reactors (PWRs, BWRs, AGRs, Magnox, fast breeders) and is ready to incorporate SMRs to the list.

It may interest you

Durability of reinforced concrete in marine environments

When properly designed, constructed, and maintained, reinforced concrete structures exhibit good durability in marine environments.

Durability, evaluation and remediation (and 2)

Sustainability improves when things last longer. The many challenges undergone by structures must be anticipated, so that they are prepared to withstand them.

Underground nuclear shelters

Principia has gathered considerable experience in evaluating the effects of terrorist and other explosions, including nuclear blasts.

Disproportionate collapse

Disproportionate collapse has always been a risk for large buildings, but the events are rare.

Durability, evaluation and remediation (1)

Sustainability improves when things last longer. Structures undergo many challenges, some foreseen in the design, others less so.

Dams, mankind’s quest to control water

What is common to all dams is that the impounded water or tailings reaches a different level on the two sides of the dam, thus subjecting it to demands that it must withstand. And, apart from that, there are other things to consider in the design of a dam, like accidents, earthquakes, floods, slope failures, explosions, etc.

Ship impact against bridge piers

Bridges with their piers in, or close to, navigable waters are exposed to this type of accidents.

Fighting the terrorist threat

Concentrating in the case of bridges, as in many other structures, the general principles of deter, detect, delay, defend, and respond provide a layered response to the threat

When there are no catastrophes

The crucial time to consider catastrophes is when they are not occurring, so we can prepare properly for when they do.

Research

It's key to have a permanent learning attitude, with active involvement in technical forums and, particularly, with the participation in research-oriented projects.