China now ranks first in the world for total operating plus prospective nuclear power capacity, with the United States retaining the largest single operating fleet at about 95 GW, France in second place, and Russia and India filling the remaining slots in the global top five, according to the Global Nuclear Power Tracker and cross-cited national filings [S1][S3].
The combined operating-plus-prospective figure matters more than operating capacity alone, because the prospective column captures reactors announced, planned, or under construction — the pipeline that will set the 2030 generation mix. As of mid-2026, the Tracker indexes every commercial unit worldwide, country by country, with separate fields for gigawatts in operation and gigawatts on the books [S3].
Operating Capacity by Country: The Top Five
The United States operates the world's largest nuclear fleet at roughly 95 GW across about 90 reactors, the legacy of a 1970s-80s build-out that has aged into 60- and 80-year licence-extension cases [S1][S3]. France holds second position in operating capacity at around 61 GW from 56 reactors, the densest per-capita nuclear base in any major economy, a result of the Messmer Plan of the 1970s that deliberately traded fossil import dependence for domestic baseload [S1][S3].
China sits third in operating capacity with an installed base that has crossed the 50 GW mark, having started 2024 below 50 GW and added multiple AP1000, Hualong One and CPR-1000 units since [S1][S3]. Russia runs about 27 GW from 37 reactors, several of them floating or barge-mounted small modular designs on the Akademik Lomonosov class [S1][S3]. South Korea rounds out the top five operating fleets at roughly 24 GW, the only OECD-Asia member with continuous new-build activity through the 2010s [S1][S3].
Prospective Pipeline: Where the Next 100 GW Will Be Built
Prospective capacity — announced, planned, and under-construction reactors combined — is the metric that has reshaped the global ranking since 2020, and it is the metric in which China now leads outright, with roughly 100+ GW in various pre-commercial stages including Hualong One, ACP100, CFR-600 supporting units, and a wave of inland coastal sites in Jiangsu, Shandong, and Hainan [S1][S3].
India's prospective column runs around 20 GW, anchored by the indigenous 700 MW PHWR fleet at Kakrapar, Kaiga, and Rajasthan, plus Russian-built VVER-1200 units at Kudankulam [S1][S3]. Russia's pipeline is the densest in fast reactors, with BN-1200 and BREST-300 lead units and a long-announced floating SMR export line aimed at Arctic and African customers [S1]. Together, BRICS bloc prospective capacity now outpaces the combined OECD pipeline outside France, South Korea, and a thin UK EDF-led slate [S1].
How Capacity Translates Into Generation Share
Installed capacity is not the same as electricity delivered, and the two diverge sharply in countries with low capacity factors or seasonal load-shaping.
Japan operated 33 reactors as of mid-2024, generating a fraction of pre-2011 output, with 15 restarted and 10 in restart review — a fleet that previously supplied about 30% of national electricity and is targeted to reach at least 20% by 2030 from a depleted baseline [S5]. China's nuclear power generation is projected to account for 10 percent of the country's total electricity, per State Council-aligned reporting, and a State Council white paper targets installed nuclear power capacity of 58 GW by 2020, with an additional 30 GW under construction at the time of issuance [S2, S6]. For comparison, global CO₂ emissions remain dominated by the United States, China, and India, which is why even small nuclear share-gains in those three jurisdictions carry outsized carbon impact [S4].
Reactor Technology Bands by Country
Pressurised water reactors (PWRs) dominate global commercial output, including the Westinghouse AP1000 in the U.S. and China, the VVER-1200 in Russia, India, Turkey, and Egypt, the EPR in France, Finland, and the UK, and the Hualong One (HPR1000) in China and Pakistan [S3]. Boiling water reactors (BWRs) remain a U.S. and Japan-specific legacy, with no major G7 economy ordering new BWRs since 2010 [S3].
Heavy water reactors (PHWRs) are an Indian and Canadian specialty — the 700 MW Indian PHWR is the workhorse of Nuclear Power Corporation of India Limited, while Canada's CANDU line exports to Romania, Argentina, and South Korea [S3]. Fast neutron reactors, gas-cooled reactors, and molten salt demonstration units are limited to Russia (BN, BREST), China (HTR-PM at Shidaowan, rated 200 MW twin-reactor), and a small set of national laboratories; none have yet reached commercial scale, and capacity figures for them are typically reported as single units rather than fleet gigawatts [S3].
Standards, Siting and Grid Integration
All commercial reactors in the top five operating countries operate under national nuclear regulators that map to IAEA safety standards (IAEA SSR-2/1 and the SF-1 safety fundamentals), with European operators additionally bound by EUR and Western European Nuclear Regulators Association (WENRA) reference levels, and U.S. operators under the U.S. Nuclear Regulatory Commission [S3]. New-build licensing in the U.S. has shifted toward 60-year licence renewal of the 1970s fleet and Part 52 combined licence reviews for AP1000 and BWRX-300 small modular units [S3].
Grid integration constrains how fast new capacity can be absorbed, particularly in China where coastal load centres are within 200-400 km of approved sites and inland sites face higher seismic and water-availability class requirements. For procurement planners sourcing ancillary equipment — from power transformer step-ups rated to IEEE C57 series to power cable runs to the switchyard and power meter panels at the unit auxiliary board — nuclear-spec hardware typically demands IEEE Class 1E qualification, IEC 61508 SIL-rated safety functions, and seismic IEEE 344 envelope documentation that conventional thermal and hydro projects do not require [S3].
Limitations of the Headline Numbers
The headline operating-plus-prospective metric in the Global Nuclear Power Tracker double-counts different risk classes: reactors in commercial operation are baseload assets delivering revenue today, while announced units may never break ground, and planned units are still subject to financing, licensing, and political risk [S3]. The Tracker's 2026 mid-year dataset should therefore be read as an upper-bound scenario for each country's pipeline, not a forecast.
Capacity figures also exclude shutdown or decommissioning units in long-term safestore, which understates the U.S. and Japan baselines by several gigawatts each, and exclude research reactors below commercial thermal thresholds [S3]. Generation share figures are point-in-time and miss the seasonal output of French, Korean, and Canadian fleets that follow load-following schedules rather than flat-baseload dispatch. For industrial buyers, the operational signal to track is unit restart approvals in Japan and the U.S. NRC 60-year licence renewals, both of which directly affect regional baseload availability for the dc power supply and switchgear supply chains feeding new-build sites [S5].
For a cross-sector read on the cost and capacity structure that drives heavy-equipment and steel-pipe supply into nuclear new-build, see the China steel pipe suppliers 2026 capacity and sourcing map, which covers the same vendor-capacity logic that constrains reactor component sourcing. Trackable signals into Q4 2026: the next IAEA PRIS data drop for verified grid connections, Japan's Nuclear Regulation Authority (NRA) restart approvals for the 10 reactors in review, and the State Council's mid-cycle review of the 2021-2025 five-year plan nuclear allocation [S3][S5].