
Apollo Atomics
We make the most compact nuclear machines.
$10M
Seed round (raising)
Earmarked for the A-1 MW-scale facility
40x
More compact than a conventional plant
One component changed: the steam generator
2028
NRC construction permit target
Pre-application docket 99902160
Backed by Y Combinator (P26, group partner Tom Blomfield) and Orange Collective, alongside Genesis Fund, Intuition, New Era Ventures, Paperjet Ventures, and the US National Science Foundation.[7]
Thesis
- 01
The demand is contracted, not hypothetical. In twenty months, Microsoft, Google, Amazon, and Meta signed roughly 16 GW of nuclear supply deals — and IEA counts 20+ GW of SMRs that tech companies plan to finance. Customers who need power in 2030 are being told to wait until 2035.[14] [16] [20]
- 02
One component changed, everything else proven. The Compact Steam Generator is 20x smaller at the same thermal power, shrinking the full plant ~40x — while keeping the pressurized water reactor design that runs ~80% of the world's nuclear fleet, light water coolant, and standard low-enriched uranium. Every funded competitor of note is betting on a new reactor type; Apollo is betting on a heat exchanger.[2] [4]
- 03
The supply chain already exists. Fuel is off the shelf from Framatome and Westinghouse, while HALEU-dependent competitors are queued behind an enrichment supply that has produced ~920 kg to date — a constraint that already delayed TerraPower's Natrium by two years. BWXT, Siemens Energy, ABB, and Framatome are under commercial agreements for the rest.[26] [31] [32]
- 04
Regulation just flipped from headwind to tailwind. EO 14300 caps new-reactor licensing decisions at 18 months, Part 53 became a final rule in April 2026, and the NRC is already running reviews on 9–17-month schedules. Apollo's regulatory engagement plan for the A-10 is docketed (ML26092A282), targeting a construction permit by 2028.[5] [8] [11] [12]
- 05
The rare team that has operated, designed, and manufactured. Assil spent a decade across EDF's SMR design team, reactor operations in Belgium, and an MIT PhD that spins out 15+ years of compact-steam-generator research under Prof. Koroush Shirvan. Drew scaled manufacturing at electric truck and boat companies after 3.5 years of White House operations; the head of manufacturing built battery lines at Tesla and Rivian and built Apollo's test reactor at MIT.[36] [37] [38]
Problem
Everyone wants nuclear. Nobody can have it on time.
Data center electricity demand roughly doubles to ~945 TWh by 2030 on IEA numbers; Goldman pegs the growth at +165% versus 2023. The hyperscalers have already decided nuclear is the answer for firm, clean power — that part of the debate is over.[13] [15]
The problem is the clock. Gigawatt-scale nuclear takes 10+ years and ~$20B per plant. Most SMRs in development rely on exotic fuels, unproven coolants, or supply chains that don't exist yet — credible delivery dates start in the 2030s. And the fast fossil alternative is gone: gas turbines are effectively sold out through 2030.[2] [33]
Customers with 2028–2035 power needs — data centers, industrial heat users, utilities — have demand today and no nuclear option that ships on their timeline.[2]
Data center electricity demand roughly doubles by 2030
Chart
Global data center electricity consumption, TWh. Endpoints are IEA Energy & AI estimates (~415 TWh in 2024 to ~945 TWh by 2030); intermediate years interpolated at the implied ~14.7% CAGR.
Source · IEA, Energy & AI (2025)
Why Nuclear, Why Now
The buyers, the government, and the regulator all moved within 20 months.
Three independent forces converged: hyperscalers signing gigawatt-scale nuclear PPAs, a 400 GW national capacity target, and the fastest NRC reform in the agency's history.
Hyperscalers contracted ~16 GW of nuclear in 20 months
Chart
Announced or contracted capacity per deal. Microsoft–Constellation Crane restart (835 MW, Sep 2024); Google–Kairos (500 MW by 2035); Amazon–X-energy (5 GW by 2039); Meta–Constellation Clinton (1.1 GW); Amazon–Talen Susquehanna (1.92 GW through 2042, ~$18B); Meta's Prometheus deals with Oklo, TerraPower, and Vistra (up to 6.6 GW by 2035).
Source · Constellation · Kairos · POWER · Talen · CNBC · Utility Dive (2024–2026)
Washington rewired the rules in one year.
May 23, 2025. Four executive orders set a national target of quadrupling nuclear capacity from ~100 GW to 400 GW by 2050. EO 14300 ordered the NRC to decide new-reactor applications within 18 months and license renewals within 12 — with a wholesale rewrite of its regulations on an 18-month deadline.[8] [9]
March–April 2026. Part 53 — the first technology-inclusive, risk-informed licensing framework — became a final rule, effective April 29. A companion proposed rule lets the NRC directly leverage DOE-authorized test reactor results in commercial reviews. The agency is already running real dockets on 9–17-month schedules, and TerraPower received the first commercial advanced-reactor construction permit in decades.[11] [12] [25] [44]
One year in. DOE's own retrospective: 11 reactor pilot projects selected, the DOME test bed open at Idaho National Lab, $2.7B committed to restoring enrichment capability, and 31+ countries signed onto tripling global nuclear capacity by 2050.[10] [39]
Energy infrastructure now demands reliability, rapid deployment, and strict cost discipline more than ever before.
The Compact Steam Generator
Change one part. Shrink the whole plant 40x.
The steam generator is the physically dominant component of a pressurized water reactor — and the only one Apollo touches.
The steam generator is why nuclear plants are buildings instead of machines.
A commercial PWR steam generator stands up to 70 feet tall, weighs 300–800 tonnes, and contains thousands of hand-assembled U-tubes; a plant needs two to six of them. They are among the largest and most expensive hand-built components in all of industry — and their size dictates the containment building, the construction schedule, and ultimately the decade-long timeline.[35]
Apollo's Compact Steam Generator replaces that vessel with a component 20x smaller at the same thermal power — per the launch video, "thousands of needles through 5% of the space" — cutting the plant's overall footprint by ~80% in volume terms and making the full system roughly 40x more compact: pre-tested, factory-built, transportable, and contracted at a fixed price.[2] [4]
Everything else stays inside the NRC's comfort zone: light water, standard low-enriched uranium, fuel and components from existing qualified supply chains, and the PWR architecture backed by 15,000+ reactor-years of global operating experience.[2] [7]
300 MW
Apollo's largest truck-transportable unit
A-300, targeted 2031
70 MW
Next closest transportable competitor
Most of the market sits at ~10 MW
<24 mo
Target deployment time
Versus 10+ years for conventional builds
The research lineage
Roadmap
Three reactors, each on a truck, each for a different customer.
A-10 for data centers, A-50 for industrial heat and small grids, A-300 for utilities — preceded by the A-0 demonstrator (built) and the A-1 MW-scale test facility this seed round funds.[2]
2026
BuiltA-0 demonstrator
- Power
- Demonstrator
- Scope
- CSG · commercial PWR conditions
Working demonstrator built and tested at MIT, reproducing commercial PWR temperatures, pressures, and water chemistry. Being shown at YC Demo Day; feeds the first NRC topical report.
2026 (target)
NextFull-scale CSG demo
- Power
- Full thermal scale
- Scope
- Compact steam generator
First full-scale demonstration of the compact steam generator — the single component that shrinks the whole plant. Validation data runs through the MIT NSE two-loop test collaboration.
2027 (target)
NextA-1 facility
- Power
- ~1 MW
- Scope
- Multi-coolant test loop
The $10M seed builds this. MW-scale multi-coolant testing — the same class of facility Radiant, Valar, and Aalo are building, after raising hundreds of millions each.
NRC Licensing Path
Already on the docket — in the lane the NRC knows best.
Apollo filed its Regulatory Engagement Plan with the NRC on April 2, 2026 (ADAMS ML26092A282, pre-application docket 99902160) — publicly searchable, signed by Halimi, and specifically scoped to licensing the A-10. The plan targets a construction permit application by 2028.[5] [6]
Two topical reports on the steam generator technology are planned for submission this year, built on A-0 and A-1 test data. Because the CSG is the only novel component, the licensing surface area is a fraction of what an entirely new reactor type carries — the NRC has approved PWR physics dozens of times.[2]
The sober counterweight: prediction markets price a new-reactor license being granted in 2026 at just 24%. The EO-driven clocks are young, and the 2028 target leans on them holding. Apollo's hedge is design conservatism — when reviews drag, exotic designs wait longest.[40]
Supply Chain
The quiet moat: Apollo buys what competitors must invent.
Fuel is the field's single biggest hidden bottleneck.
Fuel. Most funded SMR challengers — Oklo, X-energy, TerraPower, Radiant, Antares — need HALEU, a fuel the US has produced roughly 920 kg of, total, against multi-tonne per-reactor needs. Domestic enrichment covers an estimated 10–25% of projected 2050 demand, and the shortage already pushed TerraPower's Natrium out two years. Apollo's standard low-enriched uranium ships commercially today from Framatome and Westinghouse.[26] [31] [32] [43]
Components. BWXT — sole manufacturer of nuclear components for the US Navy, with a $6B backlog — has a commercial agreement for pressure vessels. Siemens Energy supplies turbines; ABB and Framatome handle instrumentation and control. Nothing in the bill of materials requires a factory that doesn't exist.[34]
Turbines. Steam turbines carry a 2–3 year backlog — tight, but a different world from gas turbines, which GE Vernova expects to be sold out through 2030 with ~3-year lead times. Apollo's stated goal is compressing typical 5–10 year nuclear vendor lead times to 2 years for first delivery.[33]
Competitive Landscape
Everyone else is inventing a new reactor. Apollo is shrinking a proven one.
The funded field divides on one axis: exotic fuel/coolant combinations that need new supply chains, versus conventional PWR + standard LEU that doesn't. Apollo is nearly alone in the second camp at truck scale.
The exotic-fuel field has raised billions; Apollo's bet is $10M
Chart
Approximate total capital raised. TerraPower includes a $2B DOE award; X-energy includes its ~$1.1B April 2026 IPO. Orange = conventional PWR + standard LEU; gray = designs requiring HALEU, TRISO, sodium, or molten salt. Radiant, Valar, and Aalo are each building MW-scale test facilities comparable to Apollo's planned A-1.
Source · TechCrunch · TerraPower · TNW · DCD · Business Wire (2025–2026)
Use already approved reactors, existing fuels, standard uranium, and regulatory pathways — and reduce the time to build from over 10 years to two.
Founder Deep Dive
From our call with Assil and Drew.
Founders & Team
The early team also includes a head of manufacturing who spent ~2 years scaling battery manufacturing lines at Tesla and Rivian — and built Apollo's test reactor at MIT.
Risks & Mitigations
What We're Watching
References
- [1]Apollo Atomics — YC Profile
- [2]Launch YC — Apollo Atomics: The Modern Nuclear Company
- [3]Apollo Atomics — Company Website
- [4]Apollo Atomics — Let's Build It (launch video, May 2026)
- [5]NRC ADAMS ML26092A282 — Apollo Atomics Regulatory Engagement Plan for the A-10 (Apr 2, 2026, docket 99902160)
- [6]PR Newswire — Apollo Atomics Announces Research Collaboration with MIT's Department of Nuclear Science and Engineering (Apr 2026)
- [7]Glitchwire — Apollo Atomics Is Building Nuclear Reactors an Order of Magnitude Smaller Than Existing Plants (May 2026)
- [8]White House — EO 14300: Ordering the Reform of the Nuclear Regulatory Commission (May 23, 2025)
- [9]World Nuclear News — Trump sets out aim to quadruple US nuclear capacity
- [10]DOE — One Year After Executive Orders, US Nuclear Energy Renaissance Is in Full Swing (May 2026)
- [11]American Action Forum — New NRC Nuclear Reactor Licensing Rule (Part 53, final Mar 30, 2026)
- [12]NRC — Licensing Efficiencies (ADVANCE Act + EO 14300 implementation)
- [13]IEA — Energy & AI, Executive Summary
- [14]IEA — Energy & AI, Energy Supply for AI
- [15]Goldman Sachs — AI to drive 165% increase in data center power demand by 2030
- [16]Constellation — Crane Clean Energy Center: 835 MW, 20-year Microsoft PPA (Sep 2024)
- [17]Kairos Power — Google partnership to deploy 500 MW (Oct 2024)
- [18]POWER — Amazon backs 5 GW X-energy SMR deployment (Oct 2024)
- [19]Talen Energy — Amazon 1,920 MW Susquehanna PPA through 2042 (Jun 2025)
- [20]CNBC — Meta signs nuclear deals to power Prometheus AI supercluster (Jan 9, 2026)
- [21]Utility Dive — Meta nuclear deals with Oklo, Vistra, TerraPower
- [22]DOE — Initial Selections for New Reactor Pilot Program (Aug 2025)
- [23]TechCrunch — Nuclear startup X-energy raises ~$1B in data-center-driven IPO (Apr 24, 2026)
- [24]TerraPower — $650M fundraise incl. Nvidia NVentures (Jun 2025)
- [25]ANS — TerraPower begins construction on Natrium plant in Kemmerer (Apr 2026)
- [26]World Nuclear News — HALEU fuel availability delays Natrium reactor
- [27]DCD — Equinix-backed microreactor firm Radiant raises $300M
- [28]TNW — Valar Atomics raises $450M at $2B valuation
- [29]Gizmodo — California startup claims historic first in fission reactor milestone (Valar, Nov 2025)
- [30]Business Wire — Aalo Atomics secures $100M Series B for AI data center nuclear (Aug 2025)
- [31]NucNet — DOE extends Centrus contract to produce crucial HALEU (~920 kg to date)
- [32]Breakthrough Institute — Abundant Fuels for Abundant Reactors (HALEU supply gap)
- [33]Utility Dive — GE Vernova: ~80 GW gas turbine backlog, sold out through 2030
- [34]StockTitan — BWXT announces $1.4B in naval nuclear propulsion contracts
- [35]Wikipedia — Steam generator (nuclear power)
- [36]Nuclear Engineering and Design — The design of a compact integral medium size PWR (Shirvan et al., 2011)
- [37]Nuclear Engineering and Design — Impact of core power density on economics of a small integral PWR (Halimi & Shirvan, 2021)
- [38]MIT NSE — Assil Halimi: Working to Make Nuclear Energy More Competitive
- [39]DOE — COP28 Declaration to Triple Nuclear Energy Capacity by 2050
- [40]Polymarket — US grants license for new nuclear reactor in 2026?
- [41]Business Wire — NuScale 77 MWe SMR achieves NRC Standard Design Approval (May 2025)
- [42]ANS — Ten companies named for fast-tracked reactor pilots: what to know
- [43]Sightline — Low-enriched uranium could offer faster deployment of small reactors (Mar 2026)
- [44]Federal Register — NRC reviews of reactor designs previously authorized by DOE or Department of War (proposed rule, Apr 2, 2026)


