The nuclear energy boom is no longer just about promises. As the third quarter draws to a close and we look ahead to the fourth quarter of 2026, retired nuclear plants are moving toward restarts, small modular reactors are entering construction, and billions of dollars are flowing into the domestic nuclear fuel supply chain.
But here's something you must understand: The U.S. still gets nearly all its nuclear electricity from the existing reactor fleet. So while advanced nuclear companies receive most of the attention, the fastest way to increase nuclear generation is to keep existing reactors running, increase their output, and restart plants that were previously shut down.
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Old nuclear is becoming valuable again
The U.S. Department of Energy (DOE) wants to add 2.5 gigawatts of nuclear capacity by 2027 and 5 gigawatts by 2029 through reactor uprates, restarts, efficiency improvements, and extending the lives of existing plants. And we're already seeing that strategy play out.
Nuclear energy company Holtec is working to restart the 800-megawatt Palisades nuclear plant in Michigan with support from a $1.52 billion DOE loan. If successful, Palisades would become the first retired U.S. commercial nuclear plant to return to service after being decommissioned.
Constellation Energy (CEG +2.02%) is also working toward restarting Pennsylvania's 835-megawatt Crane Clean Energy Center (formerly part of Three Mile Island), backed by a $1 billion federal loan.
Small modular reactors are finally being built
While retired plants get a new lease on life, the more unique long-term opportunity remains advanced nuclear power, particularly because development is underway.
Ontario Power Generation began construction of the first of four GE Vernova (GEV +0.00%) Hitachi small modular reactors at Canada's Darlington nuclear site in 2025. Construction of the first unit is underway, while BWX Technologies (BWXT +6.07%) is manufacturing its reactor pressure vessel.
If everything stays on schedule, construction of the first 300-megawatt reactor is expected to be completed by the end of 2029, with commercial operation targeted by the end of 2030, potentially making it the first commercial SMR operating in the Western world.
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Indeed, the economics are worth watching. The first unit is expected to cost about $5.5 billion, while all four are projected to cost $15 billion as efficiencies from repeated construction bring costs down. That's exactly what SMR developers have been promising for years: Build the same reactor repeatedly, and costs should fall.
Advanced reactors are moving beyond PowerPoint
There's progress elsewhere, too. Oklo (OKLO -5.03%) announced in August that its Groves Test Reactor in Texas achieved a major operational milestone less than a year after groundbreaking, successfully demonstrating a sustained nuclear chain reaction for the first time.
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TerraPower received a Nuclear Regulatory Commission (NRC) construction permit for its Natrium reactor in Wyoming in March and broke ground the following month. Meanwhile, NuScale Power (SMR -0.65%) has an NRC-approved uprated SMR design, while newly public X-energy (XE -0.22%) is advancing its Xe-100 reactor with customers including Amazon (AMZN -1.87%) and Dow (DOW -0.20%).
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X-energy says its potential project pipeline includes 144 reactors representing about 11.5 gigawatts, assuming customers exercise their contingent rights in full. That's meaningful progress. But potential projects aren't operating reactors, and you shouldn't treat them as guaranteed revenue.
AI is accelerating nuclear development
Artificial intelligence (AI) has become one of the biggest catalysts for nuclear power's resurgence. Data centers need enormous quantities of reliable electricity, and nuclear plants can provide power around the clock. But AI is also beginning to influence how reactors are developed.
X-energy recently joined Idaho National Laboratory, Nvidia (NVDA -1.51%), and Amazon Web Services in Project Prometheus, a three-year initiative using AI to accelerate reactor engineering, licensing, manufacturing, and deployment. If these tools can shorten development timelines, AI could help nuclear companies on both sides of the equation by creating electricity demand while lowering the time and cost required to build reactors.
Fuel may be the overlooked opportunity
Building reactors doesn't matter if there's no fuel available to run them. That's why the DOE awarded $2.7 billion in orders to expand domestic uranium enrichment capabilities, including production of low-enriched uranium and high-assay low-enriched uranium, or HALEU. That creates opportunities beyond reactor developers, including uranium miners, enrichment companies, fuel manufacturers, and nuclear-component suppliers.
Make no mistake: The nuclear boom is real. But commercialization is what matters.
Companies such as Constellation already generate electricity and cash flow. Suppliers such as BWX Technologies can benefit as construction expands. Companies like Oklo, NuScale, and X-energy potentially offer much greater upside, but they also carry much greater risk. Licensing delays, construction cost overruns, fuel shortages, financing requirements, and dilution also remain very real concerns.
Still, the nuclear renaissance has finally moved beyond PowerPoint presentations. Now we just have to figure out which companies can turn that momentum into profits. And we'll definitely get more clarity on that in the next few quarters.
