Nuclear Power
440 commercial reactors operate worldwide with 396 GW of installed capacity, generating roughly 9% of global electricity and a quarter of all low-carbon power. New construction is concentrated in China (28 reactors under build) and Russia. SMR demonstration projects are advancing in the US, Canada, the UK and South Korea.
Key insights
China is the only place actually building
China has 28 reactors under construction — more than the rest of the world combined excluding Russia. The CAP1400 (Hualong One) is a standardized indigenous PWR design built on roughly 5-year construction schedules at $3,000–4,000/kW. Russia (Rosatom) is the leading exporter with builds in Turkey, Egypt, Bangladesh, India and Hungary.
France remains the nuclear archetype
56 reactors supply 65–70% of French electricity — the highest share of any major economy. Output dropped to 49% in 2022 because of stress-corrosion issues but has recovered to historical norms. EDF and the French state are committed to six new EPR2 reactors by 2042, though no first-of-a-kind EPR has been built on schedule yet.
SMRs are the bet, not yet the reality
Small Modular Reactors aim for 50–300 MW units built on factory production lines. NuScale (US), GE-Hitachi BWRX-300, Rolls-Royce SMR (UK) and Korea Hydro's i-SMR are the leading designs. First commercial operation is targeted for 2029–2031. The economic case rests on serial production reducing the cost over the first 5–10 units; that hasn't yet been demonstrated.
Operating reactors by country (2026)
Number of commercial reactors connected to the grid
Key Finding: USA (94) and France (56) dominate the installed fleet; China is the largest builder of new capacity.
Nuclear share of electricity — selected countries (2025)
% of total electricity generation
Key Finding: France leads at ~65–70%; the US sits at 19%. Several long-time nuclear countries (Germany, Italy) have exited or are exiting the technology.
Methodology & caveats
Capacity vs generation
Installed capacity (gigawatts) is rated nameplate output. Generation (terawatt-hours) is what actually flows over a year. Capacity factor = generation / (capacity × hours). Modern PWRs achieve 85–92% capacity factors versus 25–35% for solar and 30–45% for wind. This 'always-on' characteristic is the nuclear case for baseload.
Levelized cost of energy (LCOE)
LCOE for new nuclear sits at $90–180/MWh in OECD countries, well above utility-scale solar+storage at $40–70/MWh. The wide LCOE range reflects construction cost overruns — Vogtle 3 & 4 came in at $14B per reactor against original estimates of $7B. China and Russia build for $3,000–5,000/kW; the US, UK and France have seen $10,000–15,000/kW recently.
Fuel and waste
A 1 GW reactor consumes about 27 tonnes of low-enriched uranium per year, producing 27 tonnes of spent fuel. Spent fuel is stored on-site in pools then dry casks; no country yet operates a deep geological repository for high-level waste (Finland's Onkalo is closest). Reprocessing extracts plutonium and uranium for reuse; France, Russia, Japan and the UK have practiced it at scale.