Small modular reactors: announcements vs concrete
Commercial SMR capacity actually under construction worldwide, MW.
About this data
Despite the volume of SMR announcements, just two commercial small modular reactors are actually under construction anywhere — a 125 MW unit in China and a 300 MW unit in Russia. Nearly all nuclear capacity being built today is large-scale, most of it above 1,000 MW per unit. The IAEA projects SMRs at 24% of new capacity by 2050 in its high case but only 5% in its low case, a spread that reflects how little has been built rather than disagreement about demand.
Small modular reactors: announcements vs concrete
Commercial SMR capacity actually under construction worldwide, MW.
Data table
| mw | series | project | source_ref | value_basis |
|---|---|---|---|---|
| 125 | smr_reality | China (commercial SMR) | iaea-ntr-2025 | One 125 MW commercial SMR under construction in China |
| 300 | smr_reality | Russia (commercial SMR) | iaea-ntr-2025 | One 300 MW commercial SMR under construction in Russia |
Methodology & sources
Last updated: Aug 14, 2026Methodology
Counts capacity where construction has formally started — first structural concrete poured — not announcements, letters of intent, site options or memoranda. That distinction is the entire point of this index: SMR press activity is enormous and SMR construction is almost nil. Just two commercial SMRs are under construction anywhere: 125 MW in China and 300 MW in Russia. Note the unit change — the SMR chart is in MEGAWATTS while the capacity chart is in GIGAWATTS, because plotting them on one axis would render the SMR bars invisible. Combined, those two projects are 0.425 GW against 78 GW total under construction. CAVEAT: the IAEA projects SMRs at 24% of new capacity by 2050 in its high case and 5% in its low case. That is an unusually wide spread and reflects how little has actually been built, not disagreement about demand. Those projections are NOT seeded here — they are scenario outputs, not measurements. Context: half of all capacity under construction is in China, which expects ~100 GW installed by around 2030. Egypt, India and Türkiye each have roughly 5 GW under way. Re-verified 2026-08-10.
Sources
- IAEA — Nuclear Technology Review 2025 ↗ IAEA — public
Comparisons are informative, not definitive. See each source for definitions and limits.