The archive · Climate & Energy · Technical decision · 2022–2026
Aalo Atomics' factory-nuclear bet: Aalo-X criticality 8 months after groundbreak
Aalo Atomics bets nuclear plants can ship like data-center gear: $100M Series B, Aalo-X groundbreak in Aug 2025, DOE-confirmed criticality by July 2026.
Aalo Atomics
What the business is
Aalo Atomics builds extra-modular reactors (XMRs): Aalo Pods pair five 10 MWe sodium-cooled Aalo-1 reactors with one turbine to make 50 MWe plants purpose-built for data centers.
Starting capital：US$100M Series B led by Valor Equity Partners (August 2025), after earlier seed and Series A rounds
How it started
Aalo Atomics was founded in Austin, Texas, by Matt Loszak and Yasir Arafat, who previously led the open-source 'Marvel' reactor design at Idaho National Laboratory. The founding bet: if more than 90% of a nuclear plant is built in factories, plants can install in months, not years, and compete with natural gas.
What happened
Aalo raised a US$100M Series B led by Valor Equity Partners in August 2025. Days later it broke ground on Aalo-X at Idaho National Laboratory — the first experimental XMR, selected under DOE's Reactor Pilot Program — with a plan to reach criticality by July 4, 2026 and power a co-located experimental data center by July 2027.
How it ended up
Aalo-X achieved zero-power fueled criticality in early July 2026 — the fourth DOE-authorized advanced reactor to hit the milestone, eight months after groundbreaking, and the first new US sodium-cooled test reactor to go critical in more than 40 years.
Background
Aalo Atomics, founded in Austin, Texas, by Matt Loszak and Yasir Arafat — who previously led the open-source 'Marvel' reactor design at Idaho National Laboratory — is betting that nuclear power plants can be assembled like data-center equipment. Its product, the Aalo Pod, bundles five 10 MWe sodium-cooled Aalo-1 reactors around one turbine into a 50 MWe plant purpose-built for AI data centers.
The company created a new category, the extra-modular reactor (XMR), between microreactors and SMRs, and pushed factory manufacturing so that over 90% of each plant is built off-site. A US$100M Series B led by Valor Equity Partners in August 2025 funded a groundbreaking at INL days later: Aalo-X, the first experimental XMR, selected under the DOE Reactor Pilot Program with a July 4, 2026 criticality deadline.
Aalo-X achieved zero-power fueled criticality in July 2026 — the fourth DOE-authorized advanced reactor to reach the milestone, eight months after breaking ground, and the first new US sodium-cooled test reactor to go critical in over 40 years. The company now targets powering a co-located experimental data center by July 2027, with a long-term goal of electricity at roughly 3 cents per kWh.
What has to be true
- Targeting AI data centers gave Aalo a creditworthy buyer with urgent power demand, letting a small startup sell 50 MWe pods instead of utility-scale plants.
- The XMR category and 90%-factory build attacked construction time and cost, the two things that have killed nuclear projects for decades.
- DOE's Reactor Pilot Program supplied a regulatory fast path and a hard deadline, compressing a normally decade-long process into months.
- The bet remains unproven at power: criticality is a test milestone; commercial electricity at 3 cents/kWh and fleet production still lie ahead.
What can be applied
A startup can compress a famously slow industry by attacking the bottleneck itself — factory build plus a regulatory fast path — but a criticality demo proves the concept, not the business model.
Aftermath
As of September 2026, Aalo-X is operating at Idaho National Laboratory following its July 2026 zero-power criticality, the fourth success in DOE's Reactor Pilot Program. The company plans to power a co-located experimental data center by July 2027 and eventually sell Aalo Pods at scale to data centers, targeting roughly 3 cents per kWh to compete with natural gas.
Sources
- Aalo-X Groundbreaking | Aalo Updates
- Department of Energy Celebrates Fourth Criticality Ahead of July 4th Goal
- Aalo Atomics raises $100M to build a microreactor and data center together
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