Nuclear energy

Nuclear power is becoming a critical aspect of meeting large hyperscale and AI companies’ commitments to become carbon-neutral or carbon-negative (see sustainability in HPC). Nuclear energy for AI first came into the spotlight when Talen Energy announced that it was selling a datacenter, powered behind the meter at the 2.5 GW Susquehanna Steam Electric Station, to AWS.¹

Since then, a number of agreements have been announced, and around a third of nuclear power plants in the US are in talks with AI companies.²

Traditional reactors

As far as I know, there is only one new nuclear reactor being built in the US: TerraPower’s Natrium plant in Kemmerer, Wyoming³ at the site of an old coal-fired plant.

There are a handful of reactors that have been recently decommissioned that are being brought back to life to support increased energy demands of AI.

• Palisades (Michigan) is an 805 MW reactor being restarted by Holtec International. US DOE offered a $1.5 billion loan, and the state of Michigan is offering $300 million.
• Three Mile Island (Pennsylvania) is an 837 MW reactor being restarted by Constellation and is bankrolled by Constellation ($1.6 billion) after Microsoft committed to pay for all its energy for twenty years.
• Duane Arnold (Iowa) is a 601 MW reactor that is under decommissioning. It has not yet been restarted, but it is one of few reactors that has not passed the point of no return in the decommissioning process.⁴

Small Modular Reactors

Small Modular Reactors (SMRs) are being actively explored as power sources for individual data center campuses, but it isn’t clear to me how long it will be before they can actually be built.

Relevant factoids:

• Larry Ellison has claimed that Oracle “secured building permits” for three SMRs to power a 1 GW data center complex.⁵
• X-Energy closed a $500M funding round led by Amazon with the ambition of deploying 5 GW of SMR capacity by 2039.⁶
• Kairos Power and Google announced a 500 MW power purchase agreement to be deployed starting in 2030.
• NuScale received approval on its SMR design in January 2023.⁷
• Palisades also has SMRs on its long-term roadmap.[^cnbc]

Both Kairos and X-Energy will use TRISO fuel.⁸

Commitments from hyperscalers

Many leading hyperscalers in the AI space have made financial commitments around nuclear technologies to date:

Hyperscaler	Energy Company	Agreement	Production Target	Reference
Microsoft	Constellation	Restart Three Mile Island; PPA for 20 years	2028	9; See also Three Mile Island.
Microsoft	Helion Energy	PPA for fusion energy	2028	10; 11
Amazon	Talen Energy	Datacenter behind the meter of Susquehanna	Immediate	1
Amazon	X-Energy	SMR	2039	6
Google	Kairos Power	SMR	2030-2035	10; 12
Oracle	N/A	SMR	N/A	5

Meta was going to plug into a nuclear power plant as well, but that plan was thwarted by bees.¹³ Since then, they have issued an RFI to find partners with whom they can deploy 1-4 GW of nuclear capacity in a geographically agnostic manner in the early 2030s.¹⁴ This implies a pace of construction that aligns with SMR technology rather than conventional large reactors.

Challenges

Nuclear is notoriously expensive and prone to cost and schedule overruns:¹⁰

Quote

“Since 1960, the U.S. has attempted to build 250 power reactors,” said Arnie Gundersen, a chief engineer at Fairewinds Energy Education, a nonprofit that opposes nuclear power. “More than half were canceled before generating any electricity. Of the remaining reactors, not one was ever completed on time and on budget.”

Footnotes

1. Amazon buys nuclear-powered data center from Talen — ANS / Nuclear Newswire ↩ ↩²

2. Tech Industry Wants to Lock Up Nuclear Power for AI ↩

3. We just broke ground on America’s first next-gen nuclear facility ↩

4. NextEra CEO says he’d ‘consider’ restarting Duane Arnold nuclear power plant ↩

5. Oracle wants to power 1GW datacenter with trio of tiny nuclear reactors ↩ ↩²

6. Amazon Invests in X-energy to Support Advanced Small Modular Nuclear Reactors and Expand Carbon-Free Power — X-energy ↩ ↩²

7. NRC Certifies First U.S. Small Modular Reactor Design ↩

8. Big Tech Is Paving the Way for a Nuclear Breakthrough ↩

9. Constellation to Launch Crane Clean Energy Center, Restoring Jobs and Carbon-Free Power to The Grid ↩

10. Amazon, Google and Microsoft Are Investing in Nuclear Power - The New York Times ↩ ↩² ↩³

11. Announcing Helion’s fusion power purchase agreement with Microsoft | Helion ↩

12. Google and Kairos Power partner on 500 MW advanced nuclear project — ANS / Nuclear Newswire ↩

13. Meta’s plan for nuclear-powered AI data centre thwarted by rare bees ↩

14. Meta joins other tech giants in turning to nuclear power ↩