The Reality of SMR Timelines for AI Data Centers: A Veteran’s View
- Tony Grayson
- Nov 21, 2025
- 8 min read
Updated: Dec 21, 2025
By Tony Grayson, Tech Executive (ex-SVP Oracle, AWS, Meta) & Former Nuclear Submarine Commander
If you’ve been following the recent nuclear boom, you’ve seen the headlines: Amazon commits to 5 GW. Google signs for advanced reactors. Oracle announces gigawatt-scale campuses. The message is clear: nuclear is the solution.
There is just one problem: GPUs move in 3-year cycles. Reactors move in decades.
I spent my early career commanding nuclear submarines, where "downtime" wasn't a metric; it was a mission failure. Later, I built data center infrastructure for Oracle, AWS, and Meta. I know the difference between a PowerPoint slide and a commissioned plant. I know what it takes to cool a reactor core versus a Blackwell rack.
While nuclear is the safest, most reliable generation method, the current wave of marketing is setting the industry up for a credibility crisis.
Below is the reality check on SMR timelines for AI data centers, HALEU fuel shortages, and what infrastructure buyers should actually do.
SMR Timelines for AI Data Centers: The Executive Summary
To optimize for decision-making, we must look at the specific delivery windows. Here is the realistic availability for nuclear power sources.
Near-Term (2025–2029): Reactor Restarts
Status: Feasible but limited.
Timeline: 3–5 years.
Examples: Palisades (Michigan) or Three Mile Island Unit 1.
Constraint: These require existing sites in good condition with willing local stakeholders.
Medium-Term (2030–2035): Gen III+ Large Reactors
Status: Proven technology, difficult execution.
Timeline: 10–14 years.
Constraint: The Vogtle Units 3 & 4 (AP1000) proved that even "off-the-shelf" designs can take a decade and cost $30B+.
Long-Term (2035–2045): Advanced SMRs (Gen IV)
Status: Experimental supply chain.
Timeline: Factory scaling likely post-2035.
Constraint: HALEU fuel availability and lack of factory fabrication lines.
If your strategy relies on SMR timelines for AI data centers intersecting with your 2028 capacity needs, you are missing the target.
The HALEU Fuel Gap: The Supply Chain That Doesn't Exist
The biggest risk to the "Advanced Nuclear" narrative is not the reactor; it is the fuel.
Many Gen IV designs (like TerraPower’s Natrium) require HALEU (High-Assay Low-Enriched Uranium).
The Demand: The DOE projects we need >40 metric tons by 2030.
The Supply: Current U.S. capacity is negligible (less than 1 ton/year).
The Problem: Prior to 2022, Russia was the primary commercial supplier.
Until domestic enrichment scales, a process that involves centrifuges, licensing, and billions in CAPEX...Gen IV SMRs have no fuel.
Regulatory Reality: The NRC Is Rigorous, Not Fast
Startups often promise "streamlined licensing." As a former operator, I can tell you that "fast" nuclear regulation is a myth you don't want to test. In the Navy, we had a saying: The specifications are written in blood. The NRC operates with a similar mindset.
The NRC licensing process generally follows three sequential steps:
Design Certification: 3–5 years.
Site License: 3–5 years.
Construction: 3–5 years.
While the Part 53 rule change aims to modernize this, we have yet to see a factory-fabricated reactor licensed and built in the U.S. under these new timelines.
The Bottom Line:
Small modular reactors represent genuine innovation, but they won't solve the AI energy crunch of 2028. If you are an infrastructure VP or CIO, you need to move beyond the press release.
1. Don't Just Buy Power; Buy the Order Book. A PPA isn't enough to move the needle on manufacturing. If you want SMRs in 2035, you need to participate in project equity or "Mankala model" structures (cooperative cost-sharing) today. You must fund the factory, not just the electrons.
2. Audit the Fuel Supply Chain. If a vendor pitches you a 2030 delivery date, ask one question: "Where is your HALEU coming from?" If they say "the spot market" or "DOE stockpiles," they are gambling with your timeline.
3. Bridge the Gap with Gas. For the next 7-10 years, the only scalable, dispatchable baseload that can support gigawatt-scale AI campuses is natural gas with carbon capture readiness. It’s not the answer we want, but it’s the answer physics dictates.
Let's build the future, but let's be honest about the calendar.
Recommended Viewing
For a deep dive into the specific challenges of integrating SMRs with industrial applications, this discussion from the OECD Nuclear Energy Agency is essential.
Frequently Asked Questions: Nuclear Power for AI Data Centers
When will SMRs be ready for AI data centers?
Realistically, commercial-scale SMR timelines for AI data centers point to 2032–2035 for the first wave of meaningful deployment. Pilot projects may appear sooner (late 2020s), but gigawatt-scale availability will lag behind current AI power demands. TerraPower's Natrium broke ground in Wyoming in June 2024 but won't achieve commercial operation until the early 2030s. NuScale received the first-ever SMR design certification in 2023 but cancelled its Utah UAMPS project due to cost overruns. The gap between announcement and electrons is measured in years, not months.
What is the difference between a PPA and a direct nuclear connection?
Most hyperscaler nuclear announcements are "virtual" PPAs (Power Purchase Agreements)—financial hedges that support the grid but do not guarantee a physical wire from the reactor to your server rack. You are still subject to local transmission interconnection queues, which can take 5+ years in congested markets. A direct connection (behind-the-meter) provides dedicated power but requires NRC co-location approval and is extremely rare. When Microsoft announces a "nuclear-powered data center," they're likely buying financial instruments, not building reactors next to servers.
What is HALEU fuel and why does it matter for SMRs?
HALEU (High-Assay Low-Enriched Uranium) is enriched to 5-20% U-235, required by many advanced SMR designs including TerraPower Natrium, X-energy Xe-100, and Kairos Power. The U.S. currently has no domestic HALEU production at scale—most supply came from Russian down-blending until 2024 sanctions cut off that source. Centrus Energy's Piketon facility is the only U.S. producer, operating at demonstration scale. This creates a multi-year supply chain bottleneck that delays SMR deployment regardless of how fast reactors get licensed.
Why are nuclear restarts faster than new SMR builds?
Restarting shuttered nuclear plants like Three Mile Island or Palisades uses existing NRC licenses, grid interconnections, trained workforce, and proven reactor designs with decades of operating history. New SMR builds require fresh NRC licensing (3-5 years minimum), first-of-a-kind engineering validation, new fuel supply chains (especially HALEU), and greenfield construction with no learning curve. Constellation's Crane Clean Energy Center (TMI restart) targets 2028—years ahead of any commercial SMR. Holtec's Palisades restart follows similar logic.
Can we use existing nuclear waste as fuel for SMRs?
Some Gen IV designs promise to consume spent fuel through reprocessing, but this technology faces significant policy hurdles in the United States. The Nuclear Waste Policy Act and proliferation concerns have blocked commercial reprocessing since the Carter administration banned it in 1977. While France and Russia reprocess spent fuel commercially, the U.S. has no infrastructure for this approach. It is not a commercial option for near-term data center power—don't let marketing materials convince you otherwise.
What should data center operators do while waiting for SMRs?
Focus on grid interconnection queue positions now—these take 5+ years in congested markets. Pursue natural gas bridge strategies with "Design for the Swap" engineering that allows future nuclear integration. Secure PPAs with existing nuclear fleet operators like Constellation, Duke, and Southern Company. Monitor restart projects like Crane Clean Energy Center and Palisades. SMRs are a 2032+ solution—current AI demand requires power today. The operators who secure grid positions and existing nuclear PPAs now will have competitive advantages when SMRs eventually arrive.
What is the NRC licensing timeline for new SMRs?
The NRC licensing process for new reactor designs takes 3-5+ years minimum for design certification alone. NuScale received the first-ever SMR design certification in January 2023 after a 6-year review that began in 2017. Combined Construction and Operating License (COL) applications add additional years before construction can begin. TerraPower Natrium, X-energy Xe-100, and Kairos Power are still working through the pipeline. The ADVANCE Act (2024) aims to streamline NRC processes, but regulatory acceleration takes years to implement.
How much power can SMRs provide to data centers?
Individual SMR modules range from 50-300 MWe depending on design. NuScale's VOYGR is 77 MWe per module (up to 12 modules = 924 MWe per plant). TerraPower Natrium is 345 MWe with 500 MWe peak using molten salt storage. X-energy Xe-100 is 80 MWe per module. For context, a hyperscale AI data center campus may require 500 MW to 2+ GW—Meta's Louisiana campus will exceed 1 GW. Multiple SMR modules or plants would be needed, requiring billions in capital and multi-year construction timelines per site.
What is the Microsoft-Constellation Three Mile Island deal?
In September 2024, Microsoft announced a 20-year PPA with Constellation Energy to restart Three Mile Island Unit 1 (renamed Crane Clean Energy Center). This 835 MW reactor—shut down in 2019 for economic reasons, not safety—will provide carbon-free power to the PJM grid supporting Microsoft's data centers. This is a restart of an existing, proven pressurized water reactor, not an SMR. It demonstrates that restarting existing nuclear plants is faster and lower-risk than waiting for Gen IV designs that have never operated commercially.
Why is nuclear baseload power valuable for AI data centers?
Nuclear provides 24/7 carbon-free baseload power at 90%+ capacity factors—the highest of any energy source. AI training clusters running NVIDIA GB200 or AMD MI300X require constant power; you can't pause a training run when the wind stops. Intermittent renewables require battery storage (expensive, fire risk) or natural gas backup (carbon emissions). Nuclear's reliability matches AI's always-on compute requirements, which is why hyperscalers are pursuing nuclear PPAs despite 2030s timelines. The alternative is curtailing AI workloads during grid stress events.
What are microreactors and when will they be available?
Microreactors are very small nuclear reactors (1-20 MWe) designed for remote locations, military bases, or distributed power. Examples include Project Pele (DoD transportable reactor), Westinghouse eVinci, and Oklo Aurora. While promising for edge data centers, mining operations, or military forward operating bases, they face the same NRC licensing bottlenecks as larger SMRs. Project Pele completed a prototype in 2024, but commercial deployments are unlikely before 2030. Don't plan your edge computing strategy around microreactor availability.
Who is Tony Grayson and why is he qualified to write about nuclear for data centers?
Tony Grayson commanded nuclear submarine USS Providence (SSN-719) with DOE/Naval Reactors certification from Admiral Rickover's program. He operated nuclear reactors from age 21, managing reactor safety for 140 sailors underwater. He serves on advisory boards for TerraPower (Bill Gates' nuclear company building Natrium) and Holtec International (pursuing Palisades restart and SMR-160). He previously led data center infrastructure at Oracle ($1.3B budget, 35+ cloud regions), Meta (30+ data centers), and AWS—giving him unique insight into both nuclear operations and hyperscale power demands.
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Tony Grayson is a recognized Top 10 Data Center Influencer, a successful entrepreneur, and the President & General Manager of Northstar Enterprise + Defense.
A former U.S. Navy Submarine Commander and recipient of the prestigious VADM Stockdale Award, Tony is a leading authority on the convergence of nuclear energy, AI infrastructure, and national defense. His career is defined by building at scale: he led global infrastructure strategy as a Senior Vice President for AWS, Meta, and Oracle before founding and selling a top-10 modular data center company.
Today, he leads strategy and execution for critical defense programs and AI infrastructure, building AI factories and cloud regions that survive contact with reality.
Read more at: tonygraysonvet.com