Amazon, Google, and Microsoft have all made big nuclear investments recently. That’s a signal that SMR technology is maturing enough for nuclear power for AI data centres.
You’re facing infrastructure decisions. Renewables lack 24/7 reliability. Traditional nuclear takes over a decade to build. SMRs promise factory-built reactors operational in the late 2020s with inherent safety advantages.
So in this article we’re going to explain what SMRs actually are, how they work, and why they differ from legacy nuclear technology. It sets the foundation for evaluating vendor claims and deployment timeline.
Let’s get into it.
What Are Small Modular Reactors and How Do They Differ from Traditional Nuclear Power Plants?
SMRs are next-generation nuclear reactors. They’re much smaller than conventional plants – generating 80-320 MW per unit compared to 1,000+ MW for the old style reactors. And instead of building everything on-site like traditional plants, they’re factory-fabricated in modules and assembled where they’ll operate.
They use advanced fuel types (TRISO) and passive safety systems that eliminate the meltdown scenarios seen in older reactor designs. The smaller footprint means you can deploy them closer to data centres with reduced emergency planning zones.
Each X-energy Xe-100 reactor provides 80 MW per module with a 60-year design life. Because of the modular nature, you can fit three 320 megawatt sections to make up a full 960 MW plant in just a few city blocks. Compare that to traditional nuclear power facilities – a single gigawatt plant can take up more than a square mile of land.
The safety and reliability claims for SMRs rest on two key innovations: the fuel itself and how the reactors manage heat without active systems. This technological leap is central to why Big Tech is investing heavily in nuclear power for AI data centres.
How Does TRISO Fuel Work and Why Is It Safer Than Conventional Nuclear Fuel?
TRISO (Tri-Structural Isotropic) fuel is clever. It consists of poppy seed-sized uranium kernels coated in multiple ceramic and graphite layers. Thousands of these particles get embedded in golf ball-sized graphite pebbles, creating individual containment vessels.
The fuel physically cannot melt even at temperatures exceeding 1,600°C due to ceramic coating properties. This eliminates meltdown scenarios possible with conventional uranium fuel rods.
Each fuel particle acts as a miniature containment structure versus traditional reactors relying on large external containment buildings. Mike Laufer, co-founder of Kairos, puts it nicely: the coatings essentially provide the key safety functions that the large containment concrete structure is providing for conventional reactor technologies.
Kairos uses TRISO fuel in its high-temperature, low-pressure, fluoride salt-cooled reactor where fuel pebbles undergo fission, generating heat that transfers to the surrounding molten salt. X-energy and Kairos Power deals plans to use TRISO fuel in its high-temperature gas-cooled reactor where helium gas runs through the reactor core.
Each fuel pebble constantly shuffles through the reactor, passing through about six times, similar to a gumball machine. The U.S. Department of Energy has been developing and testing TRISO fuel over the last two decades. If regulators approve, the built-in containment feature could shrink the footprint of nuclear plants by reducing the size of containment structures.
What Are Passive Safety Systems and How Do They Work in SMRs?
Passive safety systems function automatically without electrical power, mechanical pumps, or human intervention using physical principles like gravity, natural convection, and material properties.
When NuScale’s reactor shuts down, it can cool itself for seven days without any external power or human action. Traditional designs cannot achieve this.
SMRs with TRISO fuel rely on the ceramic coating’s properties as the primary safety mechanism. This contrasts with traditional nuclear requiring active pumps and backup generators. Fukushima demonstrated this failure mode when active cooling pumps lost power.
Think of it as graceful degradation in distributed systems. The reactor defaults to a safe state without operator intervention. This enables site-boundary emergency planning zones versus 10-mile evacuation zones for conventional plants.
How Much Power Do SMRs Generate and Can They Support Data Centre Operations?
Individual SMR modules generate 50-320 MW depending on design. X-energy’s Xe-100 provides 80 MW, while Kairos Power reactors generate about 75 MW each.
You can deploy multiple modules together to get larger capacity. Amazon’s Cascade project includes up to 12 units totalling 960 MW.
They provide continuous 24/7 baseload power unlike intermittent solar and wind requiring battery backup or gas peakers. Large AI data centres consume 100-500+ MW, so you’ll need multiple SMR modules or connection to existing nuclear or grid infrastructure.
A single large-scale AI training cluster can demand 500 megawatts of continuous power. A single hyperscale data centre may need 4-12 SMR modules depending on compute density and growth projections.
Modular deployment allows scaling capacity over time as the data centre expands. And the reliability is excellent – nuclear capacity factors exceed 95%, compared to solar at 25% and wind at 35%.
Why Are SMRs Factory-Built Instead of Constructed On-Site Like Traditional Nuclear Plants?
Factory construction enables quality control, serial production, and faster deployment versus one-off site construction. Major components get manufactured in a controlled environment, shipped to site for assembly like modular data centre infrastructure.
This reduces construction timeline from 5-10 years for traditional nuclear to projected 24-36 months for module assembly. Serial production creates learning curve benefits. Subsequent units become cheaper and faster as processes standardise.
Modular construction allows components to be built off-site and transported via rail or road. Advanced construction techniques will increase efficiency and lower costs.
Now, first-of-a-kind SMR projects face capital costs of $3,000-6,000 per kilowatt. But manufacturers project these will fall below conventional nuclear’s $7,675-12,500 per kW through series production.
Wood Mackenzie forecasts SMR costs falling to $120 per megawatt-hour by 2030 as manufacturers achieve learning rates of 5-10% per doubling of capacity.
How Do SMRs Compare to Renewable Energy for Powering Data Centres 24/7?
SMRs provide continuous 24/7 baseload power with 90%+ capacity factors regardless of weather or time of day. Solar averages 25% capacity factor, wind 35%, requiring backup power or massive battery storage.
For AI workloads requiring continuous compute, both nuclear and renewables achieve carbon-free operations, but nuclear provides reliability without the cost and complexity of battery storage.
Renewables excel for flexible workloads that can shift to times of abundant generation. Nuclear works for always-on infrastructure. Tech companies have been investing in wind and solar for the last decade, but the power from these sources is intermittent and may not be enough to meet the needs of power-intensive AI workloads.
AI training workloads cannot pause for weather versus batch processing that can shift to sunny and windy periods.
Which Companies Are Developing SMRs and What Technologies Do They Use?
X-energy is Amazon’s partner, developing the Xe-100 high-temperature gas-cooled reactor using TRISO pebble fuel. Each reactor provides 80 MW per module. The Cascade project is planned for Washington state.
Kairos Power is Google’s partner, developing a molten fluoride salt-cooled reactor using TRISO fuel. Each unit generates about 75 MW. The Hermes 2 demonstration is planned for Tennessee, with facilities operational by 2030.
TerraPower, backed by Bill Gates, is developing the Natrium sodium-cooled fast reactor. They broke ground on their reactor in Kemmerer, Wyoming, in June 2024, marking the first commercial advanced reactor construction in the United States.
Oklo is developing the Aurora powerhouse compact fast reactor, a 15 MW microreactor scale design. They secured a 12 GW Switch data centre deal.
There’s a technology split. TRISO-based designs from X-energy and Kairos versus light water SMRs from NuScale versus fast reactor approaches from TerraPower and Oklo.
Google announced the first deployment of Kairos Power’s Hermes 2 Plant in Oak Ridge, Tennessee. This marks the first purchase of electricity from an advanced Generation IV reactor by a U.S. utility, enabling 50 megawatts of nuclear energy on TVA’s grid.
What Is the Realistic Timeline for SMR Deployment at Data Centres?
First commercial SMR deployments are targeted for 2029-2030. X-energy’s Cascade and Kairos’ Hermes 2 with TVA lead the pack.
Demonstration projects will be operational 2027-2028 to prove technology before commercial scale. Full project timelines include 3-5 years for site preparation, regulatory approval, and grid interconnection, not just module assembly time.
Marketing claims of “24-month construction” refer to module assembly only, not total project delivery from decision to power generation. Widespread deployment with cost competitiveness is projected for mid-2030s after serial production ramps.
If you’re planning now for late 2020s or early 2030s data centre expansion, you can target first-generation SMR power. Earlier needs require traditional grid, nuclear, or fossil backup.
Here’s how the timeline breaks down: decision point leads to regulatory approval (2-4 years), then site prep (1-2 years), then module assembly (2-3 years), then grid interconnection and commissioning (6-12 months).
The ADVANCE Act of 2024 introduced reforms including 50% fee reductions for SMR applications and new pathways for demonstration reactors. Early site permits and design certifications can now proceed in parallel, shaving years off project timelines.
But here’s a reality check. Allison Macfarlane, former chair of the US Nuclear Regulatory Commission, is blunt: Most SMRs are on paper and haven’t progressed beyond the testing stage. She notes that commercialising the technology will be difficult because a smaller reactor core also means a less efficient reactor.
The next five years will determine whether SMRs become a cornerstone of 21st-century energy infrastructure or remain a transitional technology.
FAQ Section
Can Small Modular Reactors Have a Meltdown Like Chernobyl or Fukushima?
No. SMRs using TRISO fuel physically cannot melt because the ceramic-coated fuel particles maintain integrity above 1,600°C, far exceeding any possible reactor temperature. Chernobyl and Fukushima involved conventional fuel designs that melt when cooling systems fail. TRISO fuel’s inherent properties make meltdown impossible, not just unlikely.
How Much Does It Cost to Deploy an SMR Compared to Traditional Nuclear?
First-of-a-kind SMR projects face capital costs of approximately $3,000-6,000 per kilowatt. Manufacturers project these will fall below conventional nuclear’s $7,675-12,500 per kW through series production. Wood Mackenzie forecasts costs falling to $120 per megawatt-hour by 2030.
What Is the Difference Between an SMR and a Microreactor?
SMRs generate 50-320 MW per module and target large data centres and industrial facilities. Microreactors produce 1-20 megawatts for remote sites or military bases. Both use advanced safety features but serve different scales. Oklo Aurora at 15 MW is a microreactor. X-energy Xe-100 at 80 MW is an SMR.
How Much Nuclear Waste Do SMRs Produce Compared to Traditional Reactors?
SMRs with TRISO fuel generate less waste volume per MWh due to higher fuel burnup rates and longer operational cycles between refuelling. TRISO fuel particles provide containment at fuel level, simplifying waste handling. However, total waste characteristics depend on fuel type—some SMR designs using HALEU create different waste streams than conventional low-enriched uranium.
What Grid Infrastructure Do Data Centres Need to Use SMR Power?
Behind-the-metre co-location connects data centres directly to SMR facilities on-site, avoiding transmission costs but raising regulatory questions with FERC proceedings ongoing. Power purchase agreements deliver SMR power through existing grid infrastructure, providing stability but incurring transmission charges. Grid interconnection requirements vary by state and utility territory.
Are There Any SMRs Operating Commercially Today?
China operates the HTR-PM high-temperature gas-cooled reactor, providing commercial power since 2023, and has deployed the ACP100 SMR. Russia operates floating SMRs. No U.S. commercial SMRs are operational yet. First U.S. deployments are targeted for 2029-2030. NuScale received design certification in 2020 but no modules have been built commercially.
What Is HALEU and Why Do SMRs Need It?
High-Assay Low-Enriched Uranium (HALEU) is uranium enriched to 5-20% U-235, higher than conventional reactor fuel (less than 5%) but below weapons-grade (90%). Many SMR designs require HALEU for higher power density in smaller cores. Domestic HALEU production capacity is limited, with current supply depending on Russia. Supply chain development is necessary for U.S. SMR deployment.
How Long Do SMR Fuel Cores Last Before Requiring Refuelling?
SMR refuelling intervals vary by design. Some TRISO pebble-bed reactors continuously cycle fuel, removing spent pebbles and adding fresh ones without shutdown. Microreactors may operate for decades on single fuel loads. Longer cycles reduce operational disruption for data centre power customers.
Which Big Tech Companies Are Investing in SMRs for Data Centres?
Amazon invested $500M+ in X-energy, partnering for the Energy Northwest Cascade project producing up to 960 MW. Google signed a 500 MW agreement with Kairos Power starting 2030 across 6-7 molten salt reactors. Microsoft signed a 20-year agreement with Constellation Energy to restart Three Mile Island Unit 1, securing 837 megawatts by 2028. Oracle is designing an AI data centre to be powered by three SMRs.
What Regulatory Approvals Are Required to Deploy an SMR?
Nuclear Regulatory Commission design certification, construction permit, and operating licence are required. New Part 53 rule provides a performance-based framework for advanced reactors. Site-boundary emergency planning zone methodology has been approved for some designs like NuScale. The ADVANCE Act streamlined some processes with 50% fee reductions for SMR applications.
Can SMRs Be Deployed in Remote Locations Without Major Grid Infrastructure?
Yes. SMRs’ smaller size and modular construction enable deployment in locations impractical for traditional gigawatt-scale nuclear plants. Some designs support islanded operation or connection to smaller regional grids. Microreactors specifically target remote and off-grid applications. However, manufacturing and fuel supply chains still require transportation infrastructure access.
What Happens to Spent Fuel from Small Modular Reactors?
Spent TRISO fuel remains in ceramic-graphite containment for interim storage, similar to dry cask storage for conventional fuel but with additional particle-level containment. Long-term disposal follows the same framework as existing nuclear waste, with geological repository policy questions like Yucca Mountain unresolved. Some advanced designs claim fuel recycling potential but commercial recycling isn’t yet operational in the U.S.
