TVA / GE Vernova Hitachi BWRX-300 — Clinch River, Tennessee — The NRC issued the Tennessee Valley Authority a construction permit for a 300 MW BWRX-300 at its Clinch River site in Oak Ridge at the end of September 2026 — the first US construction authorisation for a commercial small modular reactor, and the first held by a utility rather than a reactor developer. The review took 14 months from TVA's April 2025 application, about four months ahead of the NRC's own schedule. A construction permit is not an operating licence: TVA must build the plant and obtain a separate licence before loading fuel. TVA has said the site could host up to four units; the design's first unit anywhere is Ontario Power Generation's Darlington project, targeted for 2030.
newcleo / NewHold III — Lead-cooled fast-reactor and MOX-fuel developer newcleo agreed to go public via NewHold Investment Corp III at a ~$2.4B pre-money value (up to $429M proceeds), targeting Nasdaq 'NWCL' in H2 2026. The deal closed on 21 Sep 2026 and shares began trading as NWCL on 22 Sep. Gross proceeds were $247M against up to $429M planned: an oversubscribed $216M PIPE, and only $31M from NewHold's trust — most SPAC holders redeemed rather than take shares. Former TVA chief executive Jeffrey Lyash chairs the board.
Four SMR units operate worldwide, all in Russia and China, and that count has not moved since 2023 — even as 2026 brought a construction permit, a modern licensing framework and four reactors reaching criticality in the US. A read of the gap between permits and power.
Westinghouse / NCERC (LANL, INL, NNSS) — Westinghouse's eVinci test article reached zero-power criticality at 10:39 a.m. PT on 24 Aug 2026 at the National Criticality Experiments Research Center in Nevada, with Los Alamos and Idaho National Laboratory. Zero-power criticality confirms the core's nuclear design — the reaction is self-sustaining — without generating usable heat or power, so it validates physics rather than demonstrating a working reactor. Westinghouse's 15 Sep release added the temperatures: the test article went critical at 663°C (1,225°F) and researchers measured a peak core temperature of 1,011°C (1,852°F), a record high for a reactivity measurement at NCERC — a facility record, not a technology one. Read the pair carefully: at zero power the core is not making that heat, it is held at those temperatures so the team can measure how reactivity responds to them, which is the data the prototype design needs. eVinci is a heat-pipe-cooled design with no pumps or coolant loops, sized at 5 MWe for remote sites and data centers; it was separately selected for the US Army's Janus Program at Fort Drum.
Oklo — Groves isotope test reactor, Lockhart, Texas — Oklo's Groves reactor reached first criticality at 9:19 p.m. ET on 5 Aug 2026 — a controlled, self-sustaining chain reaction less than a year after groundbreaking. It is the fifth reactor to go critical under DOE's Reactor Pilot Program and the first to do so on private land, built from scratch on a greenfield site rather than a federal laboratory campus. Groves is a low-power isotope test reactor, not a power plant: it establishes the operating base for commercial isotope production, while Oklo's Aurora power reactors remain a separate track.
Rosatom / Uzbekistan — First safety concrete was poured at the Jizzakh site near Lake Tuzkan — the first plant built anywhere under an export SMR contract. Rosatom is supplying two RITM-200N reactors (2×55 MWe) alongside two VVER-1000s for a 2.1 GW hybrid plant; first unit targeted for 2029.
Antares / Idaho National Lab — Antares' Mark 0 test reactor at Idaho National Laboratory achieved first criticality — a self-sustaining nuclear reaction and the first new US advanced-reactor design to cross the threshold (it is not yet generating power).
Oklo / US DOE — DOE's Idaho office approved the Preliminary Documented Safety Analysis (PDSA) for Oklo's Aurora-INL under the Reactor Pilot Program — a staged framework letting advanced reactors build on a federal site under DOE oversight instead of waiting on full NRC licensing. It clears the safety basis for construction (not commercial operation); Oklo pursues NRC licensing separately for commercial units.
TerraPower / UK ONR — TerraPower's Natrium design was accepted into the UK's Generic Design Assessment, with the Office for Nuclear Regulation, the Environment Agency and Natural Resources Wales beginning Step 1 in June 2026 — the sodium-cooled fast reactor's first overseas licensing push, following its US construction permit at Kemmerer. The same 345 MWe design with molten-salt storage boosting to 500 MW.
X-energy / US NRC — The NRC issued a Finding of No Significant Impact for X-energy's plan to build four 80 MWe Xe-100 reactors at Dow's Seadrift site on the Texas Gulf Coast — the first commercial nuclear project in the NRC's 52-year history cleared through a streamlined environmental assessment rather than a full environmental impact statement. The Amazon-backed developer still faces the separate safety review next.
Aalo Atomics / US DOE — US Energy Secretary Chris Wright signed authorization (25 Jun 2026, at Idaho National Laboratory) for Aalo Atomics to proceed with criticality testing of its Aalo-X critical test reactor under the DOE Reactor Pilot Program (EO 14301) — following DSA approval and an operational readiness review. The signed go-ahead is the milestone; criticality itself was expected within days (July 4 program target). Aalo-X tests the full core for the ~10 MWe Aalo-1 design.
OPG / GE Hitachi — OPG set the ~953-tonne basemat foundation module 35 m below ground for the first of four BWRX-300 units at Darlington — North America's (and the G7's) first SMR build, targeting grid connection by 2030.
Kairos Power — Kairos broke ground on Hermes 2 in Oak Ridge — the first power-producing Gen IV reactor with an NRC construction permit. The molten-salt-cooled plant will feed up to 50 MW to TVA, powering Google data centers. On 21 Sep 2026 Samsung C&T committed up to $100M — about $70M in equity, the rest as engineering services — and joined the build as a construction partner.
Big tech power deals and listed names (NuScale, Oklo) have lifted SMR sentiment, but Western first-of-a-kind units don't reach the grid until ~2030. We weigh the gap between order books and operating reactors. (Our opinion, not investment advice.)
Our read — labelled opinion, not investment advice.
TerraPower / NRC — The NRC issued a construction permit for TerraPower's Natrium plant (Kemmerer, Wyoming) — the first US commercial advanced-reactor approval in ~a decade and the first non-light-water reactor approval in over 40 years. 345 MWe sodium-cooled fast reactor with molten-salt storage boosting to 500 MW; completion targeted 2030.
US NRC — After ~6 years, the NRC finalized Part 53 (effective 29 Apr 2026) — a risk-informed, technology-inclusive licensing framework targeting design approvals in 18 months or less at roughly half the cost. A structural unlock for the entire US advanced-reactor field, independent of any single project.
Headlines feature Western startups, but the only commercial SMRs operating today are Russia's floating Akademik Lomonosov (2020) and China's HTR-PM (2023). China's Linglong One aims to be the first land-based commercial unit in 2026.
SMRs are smaller (under ~300 MWe) reactors built in factories and shipped as units, betting that repetition and standardization beat the cost overruns of giant one-off plants.
Oklo / Idaho National Lab — Oklo broke ground (22 Sep 2025) on Aurora-INL — its first Aurora Powerhouse, a 75-MWe liquid-metal-cooled, metal-fueled fast reactor at Idaho National Laboratory (building on EBR-II heritage) under DOE's Reactor Pilot Program, with Kiewit as lead constructor.
GE Vernova Hitachi 
newcleo 
TerraPower 
Oklo 
NuScale Power 
Westinghouse 
X-energy 
Aalo Atomics 
Kairos Power