71 reactors
Tick 2–4 reactors, then compare them side by side.
| First criticality | 1942 (criticality) | United States | graphite | unknown | thermal | natural uranium · metal | decommissioned | 0.0002 MWt | unknown | research, prototype | ||
| First criticality | 1945 (criticality) | Canada | heavy water | unknown | thermal | natural uranium · metal | decommissioned | 0.00001 MWt | unknown | research | ||
| First criticality | 1946 (criticality) | Soviet Union | graphite | unknown | thermal | natural uranium · metal | shutdown | 0.024 MWt | unknown | research | ||
| First criticality | 1947 (criticality) | United Kingdom | graphite | air | thermal | natural uranium · metal | decommissioned | 0.003 MWt | unknown | research | ||
| First criticality | 1948 (criticality) | France | heavy water | unknown | thermal | natural uranium · oxide | decommissioned | 0.15 MWt | unknown | research | ||
| Plutonium piles | 1943 (criticality) | United States | graphite | air | thermal | natural uranium · metal | decommissioned | 3.5 MWt | unknown | plutonium production, research, isotope production | ||
| Plutonium piles | 1944 (criticality) | United States | graphite | light water | thermal | natural uranium · metal | decommissioned | 250 MWt | unknown | plutonium production | ||
| Plutonium piles | 1948 (criticality) | Soviet Union | graphite | light water | thermal | natural uranium · metal | decommissioned | 100 MWt | unknown | plutonium production | ||
| Plutonium piles | 1950 (criticality) | United Kingdom | graphite | air | thermal | natural uranium · metal | destroyed | unknown | unknown | plutonium production | ||
| Pressurized water reactor | 1953 (criticality) | United States | light water | light water | thermal | high enriched uranium | decommissioned | unknown | unknown | propulsion naval, prototype | ||
| Pressurized water reactor | 1954 (criticality) | United States | light water | light water | thermal | high enriched uranium | decommissioned | unknown | unknown | propulsion naval | ||
| Pressurized water reactor | 1957 (criticality) | United States | light water | light water | thermal | high enriched uranium | decommissioned | 236 MWt | 60 MWe | power, prototype | ||
| Pressurized water reactor | 1960 (grid) | United States | light water | light water | thermal | low enriched uranium · oxide | decommissioned | unknown | 185 MWe | power | ||
| Pressurized water reactor | 1988 (grid) | Germany | light water | light water | thermal | low enriched uranium · oxide | shutdown | unknown | 1400 MWe | power | ||
| Pressurized water reactor | 2023 (grid) | United States, China | light water | light water | thermal | low enriched uranium · oxide | operational | unknown | 1117 MWe | power | ||
| Pressurized water reactor | 2018 (grid) | France, Germany | light water | light water | thermal | low enriched uranium · oxide | operational | unknown | 1650 MWe | power | ||
| Boiling water reactor | 1957 (grid) | United States | light water | light water | thermal | low enriched uranium · oxide | decommissioned | unknown | 5 MWe | power, prototype, research | ||
| Boiling water reactor | 1960 (grid) | United States | light water | light water | thermal | low enriched uranium · oxide | decommissioned | unknown | 197 MWe | power | ||
| Boiling water reactor | 1996 (grid) | Japan | light water | light water | thermal | low enriched uranium · oxide | shutdown | unknown | 1356 MWe | power | ||
| VVER | 1964 (grid) | Soviet Union | light water | light water | thermal | low enriched uranium · oxide | decommissioned | unknown | 210 MWe | power | ||
| VVER | 1971 (grid) | Soviet Union | light water | light water | thermal | low enriched uranium · oxide | operational | unknown | 440 MWe | power | ||
| VVER | 1980 (grid) | Soviet Union | light water | light water | thermal | low enriched uranium · oxide | operational | unknown | 1000 MWe | power | ||
| VVER | 2016 (grid) | Russia | light water | light water | thermal | low enriched uranium · oxide | operational | unknown | 1200 MWe | power | ||
| PHWR / CANDU | 1962 (grid) | Canada | heavy water | heavy water | thermal | natural uranium · oxide | decommissioned | unknown | 22 MWe | power, prototype | ||
| PHWR / CANDU | 1967 (grid) | Canada | heavy water | heavy water | thermal | natural uranium · oxide | decommissioned | unknown | 200 MWe | power, prototype | ||
| PHWR / CANDU | 1971 (grid) | Canada | heavy water | heavy water | thermal | natural uranium · oxide | operational | unknown | 515 MWe | power | ||
| PHWR / CANDU | 1982 (grid) | Canada | heavy water | heavy water | thermal | natural uranium · oxide | operational | unknown | 600 MWe | power | ||
| PHWR / CANDU | 1974 (grid) | Argentina | heavy water | heavy water | thermal | natural uranium · oxide | operational | unknown | 335 MWe | power | ||
| PHWR / CANDU | 1972 (grid) | India | heavy water | heavy water | thermal | natural uranium · oxide | shutdown | unknown | 100 MWe | power | ||
| Magnox | 1956 (grid) | United Kingdom | graphite | carbon dioxide | thermal | natural uranium · metal | decommissioned | unknown | 50 MWe | power, plutonium production | ||
| Magnox | 1971 (grid) | United Kingdom | graphite | carbon dioxide | thermal | natural uranium · metal | decommissioned | unknown | 980 MWe | power | ||
| Advanced gas-cooled | 1976 (grid) | United Kingdom | graphite | carbon dioxide | thermal | low enriched uranium · oxide | shutdown | unknown | 610 MWe | power | ||
| RBMK | 1954 (grid) | Soviet Union | graphite | light water | thermal | low enriched uranium | decommissioned | 30 MWt | 5 MWe | power, prototype, research | ||
| RBMK | 1964 (grid) | Soviet Union | graphite | light water | thermal | low enriched uranium · oxide | decommissioned | unknown | 100 MWe | power | ||
| RBMK | 1973 (grid) | Soviet Union | graphite | light water | thermal | low enriched uranium · oxide | shutdown | unknown | 1000 MWe | power | ||
| RBMK | 1983 (grid) | Soviet Union | graphite | light water | thermal | low enriched uranium · oxide | destroyed | unknown | 1000 MWe | power | ||
| Liquid-metal fast breeder | 1946 (criticality) | United States | none | mercury | fast | plutonium · metal | decommissioned | 0.025 MWt | unknown | research | ||
| Liquid-metal fast breeder | 1951 (criticality) | United States | none | nak | fast | high enriched uranium · metal | decommissioned | 1.4 MWt | 0.2 MWe | breeding, power, research, prototype | ||
| Liquid-metal fast breeder | 1973 (criticality) | France | none | sodium | fast | mox · oxide | decommissioned | unknown | 250 MWe | power, breeding, research | ||
| Liquid-metal fast breeder | 1985 (criticality) | France | none | sodium | fast | mox · oxide | decommissioned | unknown | 1242 MWe | power, breeding | ||
| Liquid-metal fast breeder | 1964 (criticality) | United States | none | sodium | fast | high enriched uranium · metal | decommissioned | 62.5 MWt | 20 MWe | power, breeding, research | ||
| Liquid-metal fast breeder | 1963 (criticality) | United States | none | sodium | fast | high enriched uranium · metal | decommissioned | unknown | 61 MWe | power, breeding | ||
| Liquid-metal fast breeder | 1973 (grid) | Soviet Union, Kazakhstan | none | sodium | fast | high enriched uranium · oxide | decommissioned | unknown | 135 MWe | power, breeding, desalination | ||
| Liquid-metal fast breeder | 1980 (grid) | Soviet Union | none | sodium | fast | high enriched uranium · oxide | operational | unknown | 600 MWe | power, breeding | ||
| Liquid-metal fast breeder | 2016 (grid) | Russia | none | sodium | fast | mox · oxide | operational | unknown | 880 MWe | power, breeding | ||
| Liquid-metal fast breeder | 1994 (criticality) | Japan | none | sodium | fast | mox · oxide | decommissioned | unknown | 280 MWe | power, breeding, prototype | ||
| Liquid-metal fast breeder | 2024 (construction start) | India | none | sodium | fast | mox · oxide | under construction | unknown | 500 MWe | power, breeding, prototype | ||
| Molten salt | 1954 (criticality) | United States | beryllium | molten salt fuel | thermal | high enriched uranium · molten salt | decommissioned | 2.5 MWt | unknown | research, propulsion space, prototype | ||
| Molten salt | 1965 (criticality) | United States | graphite | molten salt fuel | thermal | high enriched uranium · molten salt | decommissioned | 7.4 MWt | unknown | research, prototype | ||
| Molten salt | 2023 (criticality) | China | graphite | molten salt fuel | thermal | thorium u233 · molten salt | experimental | 2 MWt | unknown | research, prototype | ||
| Molten salt | 2025 (concept) | Canada, United States | unknown | molten salt fuel | thermal | molten salt | planned | unknown | unknown | power | ||
| High-temperature gas-cooled | 1965 (criticality) | United Kingdom | graphite | helium | thermal | high enriched uranium · triso | decommissioned | 20 MWt | unknown | research, prototype | ||
| High-temperature gas-cooled | 1967 (grid) | United States | graphite | helium | thermal | high enriched uranium · triso | decommissioned | 115 MWt | 40 MWe | power, prototype | ||
| High-temperature gas-cooled | 1967 (grid) | Germany | graphite | helium | thermal | high enriched uranium · triso | decommissioned | 46 MWt | 15 MWe | power, prototype, research | ||
| High-temperature gas-cooled | 1976 (grid) | United States | graphite | helium | thermal | high enriched uranium · triso | decommissioned | 842 MWt | 330 MWe | power | ||
| High-temperature gas-cooled | 1985 (grid) | Germany | graphite | helium | thermal | thorium u233 · triso | decommissioned | 750 MWt | 300 MWe | power | ||
| High-temperature gas-cooled | 2021 (grid) | China | graphite | helium | thermal | low enriched uranium · triso | operational | 500 MWt | 210 MWe | power | ||
| Heavy-water hybrids | 1967 (grid) | United Kingdom | heavy water | light water | thermal | low enriched uranium · oxide | decommissioned | unknown | 100 MWe | power, prototype | ||
| Heavy-water hybrids | 1965 (criticality) | Canada | heavy water | organic | thermal | natural uranium · oxide | decommissioned | 60 MWt | unknown | research, prototype | ||
| Sodium-graphite | 1957 (grid) | United States | graphite | sodium | thermal | high enriched uranium · metal | decommissioned | 20 MWt | 6.5 MWe | power, research, prototype | ||
| Aqueous homogeneous | 1952 (criticality) | United States | light water | light water | thermal | high enriched uranium · aqueous solution | decommissioned | 1 MWt | 0.15 MWe | research, prototype | ||
| Space & propulsion | 1965 (criticality) | United States | zirconium hydride | nak | thermal | high enriched uranium · hydride | shutdown | 0.03 MWt | 0.0005 MWe | power, propulsion space | ||
| Space & propulsion | 1959 (criticality) | United States | graphite | helium | thermal | high enriched uranium · carbide | experimental | 1100 MWt | unknown | propulsion space, research | ||
| Space & propulsion | 2018 (criticality) | United States | none | heat pipe | fast | high enriched uranium · metal | experimental | 0.004 MWt | unknown | power, propulsion space, research | ||
| SMR / Gen IV | 2023 (concept) | United States | light water | light water | thermal | low enriched uranium · oxide | planned | unknown | 77 MWe | power | ||
| SMR / Gen IV | 2024 (construction start) | United States | none | sodium | fast | low enriched uranium · metal | under construction | unknown | 345 MWe | power | ||
| SMR / Gen IV | 2025 (construction start) | United States, Canada | light water | light water | thermal | low enriched uranium · oxide | under construction | unknown | 300 MWe | power | ||
| SMR / Gen IV | 2025 (concept) | United States | graphite | helium | thermal | low enriched uranium · triso | planned | unknown | 80 MWe | power, process heat | ||
| SMR / Gen IV | 2024 (construction start) | United States | graphite | molten salt | thermal | low enriched uranium · triso | under construction | 35 MWt | unknown | power, prototype | ||
| SMR / Gen IV | 2025 (concept) | United States | none | heat pipe | fast | low enriched uranium · metal | planned | unknown | 1.5 MWe | power | ||
| SMR / Gen IV | 2021 (construction start) | China | light water | light water | thermal | low enriched uranium · oxide | under construction | unknown | 125 MWe | power, district heating, desalination |