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nuclear•chain

Who builds nuclear reactors

The nuclear steam supply system — the reactor itself — comes from a short list of vendors. 18 of them account for the 389 operating units whose designer is on record here, and the three largest built 54% of that fleet. Reactor vendors matter downstream too: a fabricator must build assemblies to the vendor's design.

VendorCountryOwnershipOperatingGW grossBuildingAll units
Rosatom RUS state 76 65.6 29 252
Westinghouse Electric Company USA private 70 73.8 2 199
Framatome FRA state 66 76.8 2 92
GE Vernova Hitachi Nuclear Energy USA jv 39 41.6 5 150
China National Nuclear Corporation CHN state 31 28.4 20 100
AtkinsRéalis (Candu Energy) CAN listed 25 18.9 — 39
Korea Hydro & Nuclear Power KOR state 20 24.1 4 33
Nuclear Power Corporation of India IND state 19 6.2 3 38
China General Nuclear Power Group CHN state 18 19.7 — 22
Mitsubishi Heavy Industries JPN listed 12 11.6 1 21
Combustion Engineering USA private 7 7.2 1 12
Babcock & Wilcox USA listed 5 4.5 — 8
State Power Investment Corporation CHN state 1 1.5 10 48
NuScale Power USA listed — — — 61
X-energy USA private — — — 16
Holtec International USA private — — — 10
BWX Technologies USA listed — — — 8
Oklo Inc. USA listed — — — 7

Vendor attribution is derived from the reactor model designation using a hand-built crosswalk, because the Global Nuclear Power Tracker carries no vendor column. Units whose model is not recorded have no vendor here rather than a guessed one.

Sources