The world's nuclear fleet in 1978
In 1978, 207 nuclear reactors were operating in 23 countries, 104.5 GWe net, with 187 under construction. 6 of those units are not included in the net capacity because no net figure has been published for them.
Compared with 1977, the operating fleet grew by 15 reactors. 20 reactors were connected to the grid that year, 16,437 MWe, mostly in Japan (5), United States (5) and France (2). 1 unit was permanently shut down, 197 MWe. The countries with the most operating capacity were United States (52,068 MWe), Japan (10,973 MWe) and Germany (6,949 MWe).
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Connected to the grid in 1978
| Unit | Country | Type | Model | MWe |
|---|---|---|---|---|
| Bruce A4 |  Canada | PHWR | CANDU 750A | 807 |
| Olkiluoto 1 |  Finland | BWR | ASEA-Atom BWR, generation III (AA-III) | 890 |
| Bugey 2 |  France | PWR | CP0 | 910 |
| Bugey 3 | France | PWR | CP0 | 910 |
| KNK II |  Germany | FBR | — | 17 |
| Unterweser | Germany | PWR | Siemens-KWU (KWU) | 1,345 |
| Caorso |  Italy | BWR | GE BWR/4, Mark II containment (BWR-4 (Mark 2)) | 860 |
| Fugen |  Japan | HWLWR | ATR | 148 |
| Fukushima Daiichi 4 | Japan | BWR | BWR-4 | 760 |
| Hamaoka 2 | Japan | BWR | BWR-4 | 806 |
| Ohi 2 | Japan | PWR | Westinghouse 4-loop (WH 4LP) | 1,120 |
| Tokai 2 | Japan | BWR | BWR-5 | 1,060 |
| Bohunice 1 |  Slovakia | PWR | VVER-440 (V-230) | 408 |
| Jinshan 2 |  Taiwan | BWR | GE BWR/4, Mark I containment (BWR-4 (Mark 1)) | 604 |
| Chernobyl 2 |  Ukraine | LWGR | RBMK-1000 (RBMK) | 925 |
| Arkansas Nuclear One 2 |  United States | PWR | Combustion Engineering 2-loop (CE 2LP) | 988 |
| Donald C Cook 2 | United States | PWR | Westinghouse 4-loop (WH 4LP) | 1,168 |
| Edwin I Hatch 2 | United States | BWR | GE BWR/4, Mark I containment (BWR-4 (Mark 1)) | 883 |
| North Anna 1 | United States | PWR | Westinghouse 3-loop (WH 3LP) | 948 |
| Three Mile Island 2 | United States | PWR | B & W (DRY) | 880 |
Shut down in 1978
| Unit | Country | Type | Model | MWe | Grid connection |
|---|---|---|---|---|---|
| Dresden 1 | United States | BWR | BWR-1 | 197 | 1960 |
Countries by operating capacity in 1978
| # | Country | Reactors | MWe | Under construction |
|---|---|---|---|---|
| 1 | United States | 66 | 52,068 | 55 |
| 2 | Japan | 18 | 10,973 | 7 |
| 3 | Germany | 14 | 6,949 | 15 |
| 4 |  United Kingdom | 33 | 6,658 | 6 |
| 5 |  Russia | 21 | 5,197 | 11 |
| 6 | Canada | 9 | 4,691 | 9 |
| 7 | France | 12 | 4,279 | 29 |
| 8 |  Sweden | 6 | 4,044 | 4 |
| 9 |  Belgium | 4 | 1,862 | 4 |
| 10 |  Switzerland | 3 | 1,103 | 2 |
| 11 |  Spain | 3 | 1,067 | 5 |
| 12 |  Bulgaria | 2 | 816 | 2 |
| 13 | Ukraine | 1 | 740 | 5 |
| 14 | Taiwan | 1 | 604 | 4 |
| 15 |  South Korea | 1 | 576 | 2 |
| 16 | Italy | 3 | 563 | 1 |
| 17 |  Netherlands | 2 | 537 | — |
| 18 | Finland | 1 | 507 | 3 |
| 19 |  India | 3 | 434 | 5 |
| 20 |  Armenia | 1 | 376 | 1 |
| 21 |  Argentina | 1 | 335 | 1 |
| 22 |  Pakistan | 1 | 90 | — |
| 23 |  Kazakhstan | 1 | 52 | — |
| 24 |  Brazil | 0 | 0 | 2 |
| 25 |  Hungary | 0 | 0 | 2 |
| 26 |  Iran | 0 | 0 | 1 |
| 27 |  Lithuania | 0 | 0 | 2 |
| 28 |  Mexico | 0 | 0 | 2 |
| 29 |  Philippines | 0 | 0 | — |
| 30 | Slovakia | 0 | 0 | 4 |
| 31 |  Slovenia | 0 | 0 | 1 |
| 32 |  South Africa | 0 | 0 | 2 |
Data: Global Energy Monitor (CC BY 4.0), IAEA PRIS 2025, Wikipedia (CC BY-SA), Wikidata and Wikimedia Commons. Capacities in net MWe unless stated.