Nuclear Reactors Under Construction 2026
By Axis Intelligence Research
Co-authors: Aidan Jad | Last updated: August 30, 2026 | License: CC BY 4.0
Seventy-nine reactors appear on the global under-construction list. Six of them are not being built. Strip out the units where work has formally stopped and 73 reactors totalling 79,478 MWe are genuinely under construction across 13 countries as of August 30, 2026 — a figure roughly one-fifth the size of the operating fleet.
Quick Answer
According to Axis Intelligence Research, 73 nuclear reactors representing 79,478 MWe of gross capacity are actively under construction worldwide as of August 30, 2026, spread across 13 countries. The World Nuclear Association lists 79 units and 85,846 MWe, but six units in four countries have construction formally suspended. China holds 53.02% of active capacity under construction.
Key Findings
- According to Axis Intelligence Research, 73 reactors totalling 79,478 MWe gross are in active construction worldwide as of August 30, 2026, once the six formally suspended units are removed from the World Nuclear Association’s list of 79.
- According to Axis Intelligence Research, the Active Construction Capacity Ratio (ACCR) stands at 92.58%, meaning 7.42% of headline under-construction capacity is attached to projects where work has stopped.
- According to Axis Intelligence Research, the Nuclear Build Concentration Index (NBCI) reads 3,085 points on a 0 to 10,000 scale, placing global reactor construction above the 2,500 threshold conventionally used to describe a highly concentrated market.
- According to Axis Intelligence Research, six countries began reactor construction between January 1 and August 30, 2026, against two countries across the whole of 2025 — a threefold widening of the group of nations pouring first concrete.
- According to Axis Intelligence Research, capacity entering construction in 2026 outpaced capacity leaving it by a Pipeline Replenishment Ratio (PRR) of 1.88, with 8,552 MWe of construction starts against 4,540 MWe of grid connections.
How Many Nuclear Reactors Are Under Construction Right Now?
The honest answer depends on who is counting and what they count.
The World Nuclear Association, in the country table it refreshed on August 28, 2026, lists 79 reactors under construction with 85,846 MWe of gross capacity across 17 host countries. The International Energy Agency, working from the IAEA Power Reactor Information System accessed on March 25, 2026, put the figure at 78 GW across 15 countries in its Global Energy Review 2026.
Both are correct. They differ because they were compiled five months apart, because one reports gross capacity and the other net, and because inclusion rules for stalled projects are not identical. We publish both rather than reconciling them quietly.
Why the reactor count differs across sources
The definitional pivot is “first concrete for the reactor.” A project can hold every licence, employ thousands of people, and have a tunnel-boring machine on site without appearing in the count. The Darlington New Nuclear Project in Ontario received its Licence to Construct from the Canadian Nuclear Safety Commission in April 2025 and cleared its first Regulatory Hold Point in March 2026, but only enters the construction tables with a start date of June 26, 2026, when the reactor building foundation went down.
That rule cuts the other way too. A unit that poured concrete in 2010 and has seen nothing since remains on the list indefinitely.
The Active Construction Capacity Ratio (ACCR)
ACCR — Active Construction Capacity Ratio™, an Axis Intelligence Research metric.
Formula: ACCR = (total listed under-construction capacity − capacity at units with construction formally suspended) ÷ total listed under-construction capacity × 100
Inputs and worked example, as of August 30, 2026:
- Total listed: 85,846 MWe gross (World Nuclear Association, August 28, 2026)
- Suspended: Carem25 in Argentina (29 MWe), Angra 3 in Brazil (1,405 MWe), Ohma 1 and Shimane 3 in Japan (2,756 MWe combined), Khmelnitski 3 and 4 in Ukraine (2,178 MWe combined) = 6,368 MWe
- ACCR = (85,846 − 6,368) ÷ 85,846 × 100 = 92.58%
The residual figure, which we call Active Construction Capacity (ACC), is 79,478 MWe across 73 reactors in 13 countries. Four countries — Argentina, Brazil, Japan and Ukraine — appear as building nations in the headline table while having no active reactor construction at all, because every unit they list is suspended.
Scope note: ACCR covers commercial grid-connected power reactors only, on a gross capacity basis. Suspension status follows the World Nuclear Association’s published designation. Research reactors, naval propulsion and floating units outside the commercial tables are excluded.
Aidan Jad, Energy and Infrastructure: The gap between 79 and 73 is not pedantry. If you are modelling when baseload capacity actually arrives on a grid, Khmelnitski 3 and 4 are not 2,178 MWe of forthcoming supply — they are two part-built VVER shells in a country under sustained attack on its power system. Angra 3 has been stop-start since 1984. Treating those as pipeline is how capacity forecasts end up wrong by a decade. The number that belongs in an interconnection study is 79,478 MWe, and even that carries schedule risk.
Which Countries Are Building Nuclear Reactors in 2026?
| Country | Units | Gross MWe | Status | Share of active capacity | Source |
|---|---|---|---|---|---|
| China | 37 | 42,142 | Active | 53.02% | World Nuclear Association, 2026-08-28 |
| India | 8 | 6,600 | Active | 8.30% | World Nuclear Association, 2026-08-28 |
| South Korea | 4 | 5,710 | Active | 7.18% | World Nuclear Association, 2026-08-28 |
| Russia | 7 | 5,342 | Active | 6.72% | World Nuclear Association, 2026-08-28 |
| Egypt | 4 | 4,800 | Active | 6.04% | World Nuclear Association, 2026-08-28 |
| Turkey | 4 | 4,800 | Active | 6.04% | World Nuclear Association, 2026-08-28 |
| United Kingdom | 2 | 3,440 | Active | 4.33% | World Nuclear Association, 2026-08-28 |
| Bangladesh | 2 | 2,400 | Active | 3.02% | World Nuclear Association, 2026-08-28 |
| Hungary | 1 | 1,200 | Active | 1.51% | World Nuclear Association, 2026-08-28 |
| Pakistan | 1 | 1,200 | Active | 1.51% | World Nuclear Association, 2026-08-28 |
| Iran | 1 | 1,057 | Active | 1.33% | World Nuclear Association, 2026-08-28 |
| Slovakia | 1 | 471 | Active | 0.59% | World Nuclear Association, 2026-08-28 |
| Canada | 1 | 316 | Active | 0.40% | World Nuclear Association, 2026-08-28 |
| Japan | 2 | 2,756 | Suspended | — | World Nuclear Association, 2026-08-28 |
| Ukraine | 2 | 2,178 | Suspended | — | World Nuclear Association, 2026-08-28 |
| Brazil | 1 | 1,405 | Suspended | — | World Nuclear Association, 2026-08-28 |
| Argentina | 1 | 29 | Suspended | — | World Nuclear Association, 2026-08-28 |
| Listed total | 79 | 85,846 | — | — | World Nuclear Association, 2026-08-28 |
| Active total (Axis) | 73 | 79,478 | — | 100% | Axis Intelligence Research, 2026-08-30 |
Our country-level sums reconcile exactly to the World Nuclear Association’s published world totals of 79 units and 85,846 MWe, which is the arithmetic check we run before any derived figure is published.
The Nuclear Build Concentration Index (NBCI)
NBCI — Nuclear Build Concentration Index™, an Axis Intelligence Research metric.
Formula: NBCI = Σ (sᵢ)² where sᵢ is country i’s percentage share of global Active Construction Capacity.
Worked example, as of August 30, 2026: China contributes 53.023² = 2,811.5 index points on its own. India adds 68.96, South Korea 51.62, Russia 45.18, Egypt and Turkey 36.47 each, the United Kingdom 18.73, Bangladesh 9.12, and the remaining five countries contribute 6.84 combined.
NBCI = 3,085 points on a 0 to 10,000 scale.
Read against the thresholds competition authorities conventionally apply to market concentration — under 1,500 unconcentrated, 1,500 to 2,500 moderately concentrated, above 2,500 highly concentrated — global reactor construction sits firmly in the highly concentrated band. A perfectly even split across the 13 active countries would score 769.
The top three countries hold 68.51% of active capacity. China alone builds 37 of the 73 active units.
Scope note: NBCI measures where reactors are being built, not who designs them. On the design side the concentration is sharper still: the IEA found that 94% of reactors that began construction over the past decade were of Chinese or Russian design.
Aidan Jad: An NBCI of 3,085 tells you something uncomfortable about supply chains. Heavy forgings, reactor pressure vessels, steam generators, qualified welders — those capabilities live where the order book lives. When a European or North American utility signs for a large unit, it is buying into a supply chain whose learning curve is being climbed somewhere else. That is not an argument against building. It is an argument for understanding why the first unit in a fresh market costs what it costs.
Which Reactors Started Construction in 2026?
Nine units began construction between January 1 and August 30, 2026, totalling 8,552 MWe net.
| Reactor | Country | Construction start | Net MWe | Source |
|---|---|---|---|---|
| Xuwei 1 | China | 2026-01-16 | 1,116 | World Nuclear Association, 2026-08-28 |
| Kursk 2-3 | Russia | 2026-01-31 | 1,200 | World Nuclear Association, 2026-08-28 |
| Paks II-1 | Hungary | 2026-02-05 | 1,100 | World Nuclear Association, 2026-08-28 |
| Kaiga 5 | India | 2026-03-01 | 630 | World Nuclear Association, 2026-08-28 |
| Kaiga 6 | India | 2026-03-01 | 630 | World Nuclear Association, 2026-08-28 |
| Jinqimen 2 | China | 2026-04-04 | 1,120 | World Nuclear Association, 2026-08-28 |
| Taipingling 4 | China | 2026-05-10 | 1,116 | World Nuclear Association, 2026-08-28 |
| Shin-Hanul-4 | South Korea | 2026-05-29 | 1,340 | World Nuclear Association, 2026-08-28 |
| Darlington SMR-1 | Canada | 2026-06-26 | 300 | World Nuclear Association, 2026-08-28 |
| Total | 6 countries | — | 8,552 | Axis Intelligence Research, 2026-08-30 |
The breadth shift nobody has quantified
This is the finding we would point a journalist to first.
In 2025, according to the IEA, there were ten construction starts totalling 12.2 GW — nine in China and one in Russia. Two countries. In the first eight months of 2026, nine units started construction across six countries: China, Russia, Hungary, India, South Korea and Canada.
According to Axis Intelligence Research, China’s share of construction starts fell from 90% of units in 2025 to 33.3% of units and 39.2% of capacity in 2026 to date. The number of countries initiating reactor construction tripled.
Capacity has not surged; breadth has. At the current run rate, 2026 annualises to roughly 12,828 MWe of construction starts, about 5% above the 2025 total. The composition is what changed. Paks II-1 is a new construction start inside the European Union. Shin-Hanul-4 restarts a Korean sequence. Darlington SMR-1 is the first grid-scale small modular reactor to reach first concrete in a G7 country.
The Pipeline Replenishment Ratio (PRR)
PRR — Pipeline Replenishment Ratio™, an Axis Intelligence Research metric.
Formula: PRR = capacity entering construction in the period ÷ capacity leaving construction via grid connection in the period.
Worked example, January 1 to August 30, 2026: 8,552 MWe of construction starts ÷ 4,540 MWe of grid connections = 1.88.
A PRR above 1.0 means the construction pipeline is growing. At 1.88, nearly two megawatts entered construction for every megawatt that graduated to the grid, adding a net 4,012 MWe to the global build queue in eight months.
Scope note: PRR uses net capacity for both flows, since grid connection is reported in net terms. It is a flow measure and says nothing about whether projects in the queue will finish on schedule.
Which Reactors Connected to the Grid in 2026?
Four reactors reached grid connection between January and August 2026. All four are in China.
| Reactor | Country | Grid connection | Net MWe | Source |
|---|---|---|---|---|
| Taipingling 1 | China | 2026-02-13 | 1,116 | World Nuclear Association, 2026-08-28 |
| San’ao 1 | China | 2026-03-12 | 1,208 | World Nuclear Association, 2026-08-28 |
| Taipingling 2 | China | 2026-07-04 | 1,116 | World Nuclear Association, 2026-08-28 |
| Changjiang-3 | China | 2026-08-01 | 1,100 | World Nuclear Association, 2026-08-28 |
| Total | — | — | 4,540 | Axis Intelligence Research, 2026-08-30 |
The World Nuclear Association records no permanent reactor shutdowns anywhere in the world during this period, which makes 2026 to date a year of pure net capacity addition — unusual after 2025, when the IEA recorded 3 GW of additions offset by 3 GW of retirements, two-thirds of the closures in Belgium.
Aidan Jad: Four grid connections, one country, and the newest is a Hualong One derivative at a site that already had units running. That is what a mature build programme looks like: repeat designs, repeat sites, shared infrastructure, and a construction crew that has done it before. Everyone outside China is currently paying the tuition fee for not having that.
How Much Do Nuclear Reactors Under Construction Cost?
Disclosed capital costs for projects currently building, each stated on the basis its owner published:
| Project | Country | Disclosed cost | Basis | Capacity | Implied per kW | Source |
|---|---|---|---|---|---|---|
| Hinkley Point C | United Kingdom | GBP 35 bn | 2015 sterling, completion cost | 3,440 MWe gross | GBP 10,174 /kW (2015) | EDF, 2025 annual results, 2026-02-20 |
| Hinkley Point C | United Kingdom | GBP 48 bn | Current value | 3,440 MWe gross | — | EDF, 2025 results presentation |
| El Dabaa | Egypt | USD 25 bn | Russian state export loan covering 85% of four units | 4,800 MWe | — | World Nuclear Association, Egypt profile |
| Akkuyu | Turkey | USD 20 bn | Value of the 2010 intergovernmental accord | 4,800 MWe | — | Turkish Ministry of Energy briefings |
| Darlington New Nuclear (4 units) | Canada | CAD 20.9 bn | 2024 dollars, incl. interest and contingency | 1,200 MWe | CAD 17,417 /kW | Ontario Power Generation |
| Darlington New Nuclear (unit 1) | Canada | CAD 7.7 bn | 2024 dollars, first-of-a-kind + shared works | 300 MWe | CAD 25,667 /kW | Ontario Power Generation |
| Kemmerer 1 | United States | USD 4.0 bn | 2021 estimate, unrevised [older data] | 345 MWe | — | TerraPower, company-reported |
Why we will not publish a single global cost-per-kilowatt figure
We could. It would be quoted widely. It would also be meaningless.
The numbers above are denominated in three currencies, fixed to price bases spanning 2010 to 2024, and built on incompatible definitions. EDF’s completion cost for Hinkley Point C excludes interim interest and is quoted in 2015 sterling. Ontario Power Generation’s CAD 20.9 billion explicitly includes interest charges and contingencies. Egypt’s USD 25 billion is a loan facility sized at 85% of project cost, not the project cost itself — and other published estimates put El Dabaa’s total between USD 28.75 billion and USD 30 billion, a spread we report rather than average away.
Averaging a loan facility, an ex-interest completion estimate, and an all-in 2024-dollar programme budget produces a figure that describes nothing. Two of these can be compared: the Darlington first unit and the Darlington four-unit programme, same currency, same vintage, same owner. First-of-a-kind carries a 47.4% per-kilowatt premium over the programme average — CAD 25,667/kW against CAD 17,417/kW. That is the fleet effect, measured rather than asserted.
What Hinkley Point C’s cost history actually shows
EDF’s own successive disclosures, all in 2015 sterling:
| Disclosure | Completion cost | Unit 1 first power | Source |
|---|---|---|---|
| May 2022 review | GBP 25–26 bn | June 2027 | EDF, via World Nuclear News |
| January 2024 revision | GBP 31–34 bn | 2029 to 2031 | EDF, via World Nuclear News |
| February 2026 results | GBP 35 bn | 2030 | EDF, 2025 annual results |
From the 2022 midpoint to the 2026 figure is a 37.3% increase in stated completion cost over under four years of disclosure, alongside a three-year schedule slip. EDF attributes the latest 12-month delay to productivity in electromechanical installation — piping and cabling — and states that a further 12-month delay would add GBP 1 billion in 2015 sterling. Construction began in 2017 against an original 2025 target; first power in 2030 implies a 13-year build.
For scale on what comes next, EDF presented a forecast cost estimate of EUR 72.8 billion in 2020 euros for the French EPR2 programme in the same set of results.
Aidan Jad: The electromechanical phase is where EPR schedules go to die, and it is the least photogenic part of the job. Nobody films cable pulling. But the civil works were largely finished at Hinkley years ago, and the plant still is not producing electrons, because a reactor is mostly pipework and instrumentation wearing a concrete coat. Anyone forecasting a completion date off a photograph of a finished dome is reading the wrong indicator.
Why Does the United States Have Zero Reactors Under Construction?
Because the count uses first concrete, and the definitional lag is currently doing a lot of work.
The World Nuclear Association’s table records zero US reactors under construction. Yet on March 4, 2026, the US Nuclear Regulatory Commission issued a construction permit for TerraPower’s Kemmerer Power Station Unit 1 in Wyoming — a 345 MWe sodium-cooled fast reactor that can push output to 500 MW using stored heat. The Department of Energy describes it as the first construction permit ever issued by the NRC for a commercial non-light-water power reactor, and the first for any commercial reactor in nearly a decade. TerraPower began non-nuclear site work in June 2024 and nuclear construction after the permit. The project targets completion in 2030.
According to Axis Intelligence Research, the United States is therefore the clearest current example of a country with active reactor construction and a reported count of zero. Anyone citing “zero US reactors under construction” without that qualifier is repeating a definitional artefact, not a fact about US industrial activity.
The same lag flatters and penalises different countries at different moments. Canada appears with a single 316 MWe unit as of June 2026 despite four years of site works and a construction licence granted in April 2025.
How Long Does It Take to Build a Nuclear Reactor?
Build duration is where the divergence between programmes shows up most starkly, and where published schedules deserve to be held against history.
| Project | Construction start | Target first power / grid | Implied duration | Source |
|---|---|---|---|---|
| Hinkley Point C unit 1 | 2017 | 2030 | 13 years | EDF, 2026-02-20 |
| Darlington SMR-1 | 2026-06-26 | End 2030 | ~4.5 years | Ontario Power Generation |
| Kemmerer 1 | 2026 (post-permit) | 2030 | ~4 years | US Department of Energy |
| Akkuyu unit 1 | 2018 | Autumn 2026 fuel load and startup | ~8 years | Rosatom / Turkish energy ministry |
Hinkley Point C was approved against an eight-year build and is now running to thirteen. Darlington and Kemmerer are both promising roughly four to four and a half years for first-of-a-kind designs, which would be faster than any Western large-reactor build this century.
We are not going to pretend those targets are equivalent to the delivered Hinkley number. One is a fourteen-year track record; the others are plans. What makes them worth tracking is that both are small units with modular construction methods and, in Darlington’s case, an owner whose Darlington refurbishment programme has run on schedule and on budget. If either lands near target, the per-kilowatt arithmetic in the cost table changes materially. If both slip the way Hinkley slipped, the SMR cost case gets considerably harder.
Definitions and Method
Collection. All observations were fetched from primary or institutional sources during production on August 30, 2026, with URLs and retrieval dates logged in the accompanying CSV. No figure in this article originates from model recall. The core country dataset is the World Nuclear Association’s world overview table as refreshed on August 28, 2026; global flow and capacity context comes from the IEA Global Energy Review 2026, itself compiled from IAEA PRIS accessed March 25, 2026. Project costs come from owner disclosures: EDF’s 2025 annual results, Ontario Power Generation’s project page, the World Nuclear Association’s Egypt country profile, and Turkish ministerial briefings. US regulatory milestones come from the US Department of Energy.
Definitions. “Under construction” follows the World Nuclear Association’s rule: first concrete poured for the reactor, or keel laying for floating plants. “Operable” means connected to the grid. Capacity is stated gross for stock figures and net for 2026 flow figures, matching the source in each case; the two are not interchangeable and are labelled per row in the CSV.
Axis formulas. ACCR, NBCI and PRR are defined with worked inputs in their respective sections above. Every input to every Axis figure is a sourced row in the CSV. All arithmetic was verified in Python before drafting, and the country-level sums were checked against the World Nuclear Association’s published world totals in both directions.
Scope. Commercial grid-connected power reactors only. Research reactors, naval propulsion, and the Akademik Lomonosov floating plant are outside the dataset. Suspension status follows the source publisher’s designation rather than an Axis judgement.
Source discrepancies we report rather than resolve. Reactor counts differ between the World Nuclear Association (79 units, 17 countries, gross) and the IEA (78 GW, 15 countries, net, five months earlier). El Dabaa’s total project cost is published variously at USD 25 billion, USD 28.75 billion and USD 30 billion depending on whether the figure describes the Russian loan facility or total project cost; we carry the loan figure with its definition attached. TerraPower’s USD 4.0 billion estimate for Kemmerer 1 has not been revised since 2021 and is flagged as older data.
Calculations we declined to run. A single global cost-per-kilowatt average, and any cross-currency cost aggregation, for the methodological reasons set out above.
About This Dataset
The CSV accompanying this article is the fact table behind every figure in the prose. It carries 127 observations across 15 columns, with source organisation, source document, absolute URL, retrieval date, primary-source flag, Axis-calculated flag and method note on every row. Values are raw: no currency symbols, no percent signs, no thousands separators. Dates are ISO 8601.
Coverage: global reactor construction stock by country, 2026 construction starts, 2026 grid connections, disclosed project costs and schedules, and all Axis-derived metrics.
License: CC BY 4.0. Attribution required.
Citation line: Axis Intelligence Research, Nuclear Reactors Under Construction, 2026.
How to Cite This Research
APA Axis Intelligence Research. (2026). Nuclear reactors under construction 2026: 73 active builds, 79.5 GW, costs and completion dates. Axis Intelligence. https://axis-intelligence.com/nuclear-reactors-under-construction/
MLA Axis Intelligence Research. “Nuclear Reactors Under Construction 2026: 73 Active Builds, 79.5 GW, Costs and Completion Dates.” Axis Intelligence, 30 Aug. 2026, axis-intelligence.com/nuclear-reactors-under-construction/.
Chicago Axis Intelligence Research. “Nuclear Reactors Under Construction 2026: 73 Active Builds, 79.5 GW, Costs and Completion Dates.” Axis Intelligence. August 30, 2026. https://axis-intelligence.com/nuclear-reactors-under-construction/.
Frequently Asked Questions
Does a reactor listed as under construction always get built?
Not reliably. Six of the 79 currently listed units have construction formally suspended, and two of them — Angra 3 in Brazil and Carem25 in Argentina — have been stalled across multiple governments. Angra 3 first began construction in the 1980s. A listing records that concrete was once poured; it does not record that anyone is working today. This is the specific failure mode the Active Construction Capacity Ratio was built to expose.
If a reactor starts construction in 2026, when does it actually reach the grid?
On current evidence, anywhere from four to thirteen years, and the spread is driven more by programme maturity than by reactor size. China connected four units in 2026 at sites with existing operating reactors and repeat designs. Hinkley Point C, a first-of-a-kind EPR in a market that had not built for a generation, is running to thirteen years. Treat any single-project schedule as design-specific and owner-specific rather than an industry norm.
Why does capacity under construction get quoted as both 78 GW and 85.8 GW?
Three reasons compound. Gross capacity includes the plant’s own auxiliary load, net does not, and the gap across a fleet this size runs to gigawatts. The IEA figure was compiled from PRIS in March 2026 and the World Nuclear Association’s in August 2026, with nine construction starts in between. And the two publishers apply different treatment to suspended units. Neither number is wrong; they measure adjacent things.
Is the small modular reactor buildout real yet, or still on slide decks?
Three commercial SMRs are physically under construction: one 125 MW unit in China, one 300 MW unit in Russia, and Darlington SMR-1 in Canada, which poured its reactor foundation in 2026. Kemmerer 1 in Wyoming holds a construction permit and is building. That is a real but small base — the four together are a rounding error against 79,478 MWe of active capacity. The economic question is unresolved: Ontario Power Generation’s first unit carries a 47.4% per-kilowatt premium over its own four-unit programme average, and whether units two through four deliver that saving is the test the entire sector is watching.
Which country will add the most nuclear capacity to its grid in the next five years?
China, and the margin is not close. It holds 37 of the 73 active builds and 53.02% of active capacity under construction, and the IEA expects Chinese installed nuclear capacity to reach around 100 GW by about 2030. Every unit connected to any grid anywhere in the world in the first eight months of 2026 was Chinese.
Does having reactors under construction mean a country has a domestic nuclear industry?
Frequently not. Egypt, Turkey, Bangladesh and Hungary are all building units supplied and largely financed by Rosatom, and Egypt’s project rests on a Russian state export loan sized at 85% of cost. The IEA found that 94% of reactors starting construction over the past decade were of Chinese or Russian design. Host-country construction and supplier-country capability are separate things, and the Nuclear Build Concentration Index measures only the first.
What would move these numbers most before the next update?
Three events. Akkuyu 1 loading fuel and connecting, which would put Turkey on the grid-connection board for the first time and remove 1,200 MWe from the construction queue. Any resumption at Khmelnitski, Angra 3, Ohma or Shimane, which would lift ACCR directly. And further construction starts, which have been running at slightly above the 2025 pace with a much wider spread of host countries.
How does capacity under construction compare with the operating fleet?
According to Axis Intelligence Research, active capacity under construction equals 18.9% of the world’s operating nuclear capacity, comparing 79,478 MWe gross of active builds against the 420 GW the IEA recorded in operation at the end of 2025. Beyond construction, the World Nuclear Association counts a further 124 planned units at 113,583 MWe gross and 331 proposed units at 300,484 MWe — categories that carry progressively weaker commitment and should not be added to the construction figure.