Editing Nuclear reactor (section)

==Early reactors==
{{See also|Nuclear fission#History}}
[[File:Stagg Field reactor.jpg|thumb|The [[Chicago Pile-1|Chicago Pile]], the first artificial nuclear reactor, built in secrecy at the University of Chicago in 1942 during World War II as part of the US's [[Manhattan project]]]]
[[File:Otto Hahn und Lise Meitner.jpg|thumb|upright=0.75|[[Lise Meitner]] and [[Otto Hahn]] in their laboratory]]
[[File:ChicagoPileTeam.png|right|thumb|Some of the [[Chicago Pile-1|Chicago Pile Team]], including [[Enrico Fermi]] and [[Leó Szilárd]]]]

The [[neutron]] was discovered in 1932 by British physicist [[James Chadwick]]. The concept of a nuclear chain reaction brought about by [[nuclear reaction]]s mediated by neutrons was first realized shortly thereafter, by [[Hungary|Hungarian]] scientist [[Leó Szilárd]], in 1933. He filed a patent for his idea of a simple reactor the following year while working at the [[British Admiralty|Admiralty]] in London, England.<ref>L. Szilárd, [http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=GB630726 "Improvements in or relating to the transmutation of chemical elements,"] {{Webarchive|url=https://web.archive.org/web/20080621120547/http://v3.espacenet.com/textdoc?DB=EPODOC|date=21 June 2008}}. British patent number: GB630726 (filed: 28 June 1934; published: 30 March 1936).</ref> However, Szilárd's idea did not incorporate the idea of nuclear fission as a neutron source, since that process was not yet discovered. Szilárd's ideas for nuclear reactors using neutron-mediated nuclear chain reactions in light elements proved unworkable.

Inspiration for a new type of reactor using uranium came from the discovery by [[Otto Hahn]], [[Lise Meitner]], and [[Fritz Strassmann]] in 1938 that bombardment of uranium with neutrons (provided by an alpha-on-beryllium fusion reaction, a "[[neutron howitzer]]") produced a [[barium]] residue, which they reasoned was created by fission of the uranium nuclei. In their second publication on nuclear fission in February 1939, Hahn and Strassmann predicted the existence and liberation of additional neutrons during the fission process, opening the possibility of a [[nuclear chain reaction]]. Subsequent studies in early 1939 (one of them by Szilárd and Fermi), revealed that several neutrons were indeed released during fission, making available the opportunity for the nuclear chain reaction that Szilárd had envisioned six years previously.

On 2 August 1939, [[Albert Einstein]] signed a letter to President [[Franklin D. Roosevelt]] (written by Szilárd) suggesting that the discovery of uranium's fission could lead to the development of "extremely powerful bombs of a new type", giving impetus to the study of reactors and fission. Szilárd and Einstein knew each other well and had worked together years previously, but Einstein had never thought about this possibility for nuclear energy until Szilard reported it to him, at the beginning of his quest to produce the [[Einstein-Szilárd letter]] to alert the U.S. government.

Shortly after, [[Nazi Germany]] invaded Poland in 1939, starting [[World War II]] in Europe. The U.S. was not yet officially at war, but in October, when the Einstein-Szilárd letter was delivered to him, Roosevelt commented that the purpose of doing the research was to make sure "the Nazis don't blow us up." The U.S. nuclear project followed, although with some delay as there remained skepticism (some of it from [[Enrico Fermi]]) and also little action from the small number of officials in the government who were initially charged with moving the project forward.

The following year, the U.S. Government received the [[Frisch–Peierls memorandum]] from the UK, which stated that the amount of [[uranium]] needed for a [[chain reaction]] was far lower than had previously been thought. The memorandum was a product of the [[MAUD Committee]], which was working on the UK atomic bomb project, known as [[Tube Alloys]], later [[British contribution to the Manhattan Project|to be subsumed]] within the [[Manhattan Project]].

Eventually, the first artificial nuclear reactor, [[Chicago Pile-1]], was constructed at the [[University of Chicago]], by a team led by [[Italians|Italian]] physicist Enrico Fermi, in late 1942. By this time, the program had been pressured for a year by U.S. entry into the war. The Chicago Pile achieved [[critical mass|criticality]] on 2 December 1942<ref name=":0">The First Reactor, U.S. Atomic Energy Commission, Division of Technical Information</ref> at 3:25&nbsp;PM. The reactor support structure was made of wood, which supported a pile (hence the name) of graphite blocks, embedded in which was natural uranium oxide 'pseudospheres' or 'briquettes'.

Soon after the Chicago Pile, the [[Metallurgical Laboratory]] developed a number of nuclear reactors for the [[Manhattan Project]] starting in 1943. The primary purpose for the largest reactors (located at the [[Hanford Site]] in [[Washington (state)|Washington]]), was the mass production of [[plutonium]] for nuclear weapons. Fermi and Szilard applied for a patent on reactors on 19 December 1944. Its issuance was delayed for 10&nbsp;years because of wartime secrecy.<ref>Enrico, Fermi and Leo, Szilard {{US Patent|2708656}} "Neutronic Reactor" issued 17 May 1955</ref>

"World's first nuclear power plant" is the claim made by signs at the site of the [[EBR-I]], which is now a museum near [[Arco, Idaho]]. Originally called "Chicago Pile-4", it was carried out under the direction of [[Walter Zinn]] for [[Argonne National Laboratory]].<ref>{{cite web|url=http://www.ne.anl.gov/About/hn/news960320.shtml|title=Chicago Pile reactors create enduring research legacy – Argonne's Historical News Releases|work=anl.gov|access-date=21 August 2013|archive-date=13 June 2022|archive-url=https://web.archive.org/web/20220613201103/http://www.ne.anl.gov/About/hn/news960320.shtml|url-status=live}}</ref> This experimental [[LMFBR]] operated by the [[U.S. Atomic Energy Commission]] produced 0.8&nbsp;kW in a test on 20 December 1951<ref>[https://inlportal.inl.gov/portal/server.pt/gateway/PTARGS_0_200_816_259_0_43/http%3B/inlpublisher%3B7087/publishedcontent/publish/communities/inl_gov/about_inl/home_page_fact_sheets/sheets/experimental_breeder_reactor___i_4.pdf Experimental Breeder Reactor 1 factsheet], Idaho National Laboratory {{webarchive |url=https://web.archive.org/web/20081029200744/https://inlportal.inl.gov/portal/server.pt/gateway/PTARGS_0_200_816_259_0_43/http%3B/inlpublisher%3B7087/publishedcontent/publish/communities/inl_gov/about_inl/home_page_fact_sheets/sheets/experimental_breeder_reactor___i_4.pdf |date=29 October 2008 }}</ref> and 100&nbsp;kW (electrical) the following day,<ref>{{cite web | url=http://www.ans.org/pubs/magazines/nn/docs/2001-11-2.pdf | title=Fifty years ago in December: Atomic reactor EBR-I produced first electricity | publisher=American Nuclear Society Nuclear news | date=November 2001 | access-date=18 June 2008 | archive-url=https://web.archive.org/web/20080625035749/http://www.ans.org/pubs/magazines/nn/docs/2001-11-2.pdf | archive-date=25 June 2008 | url-status=dead }}</ref> having a design output of 200&nbsp;kW (electrical).

Besides the military uses of nuclear reactors, there were political reasons to pursue civilian use of atomic energy. U.S. President [[Dwight Eisenhower]] made his famous [[Atoms for Peace]] speech to the [[UN General Assembly]] on 8 December 1953. This diplomacy led to the dissemination of reactor technology to U.S. institutions and worldwide.<ref>{{cite web|url=https://www.pbs.org/wgbh/nova/tech/the-nuclear-option.html|title=The Nuclear Option — NOVA {{!}} PBS|website=www.pbs.org|date=11 January 2017|access-date=2017-01-12|archive-date=3 September 2017|archive-url=https://web.archive.org/web/20170903030256/https://www.pbs.org/wgbh/nova/tech/the-nuclear-option.html|url-status=live}}</ref>

The first nuclear power plant built for civil purposes was the AM-1 [[Obninsk Nuclear Power Plant]], launched on 27 June 1954 in the [[Soviet Union]]. It produced around 5&nbsp;MW (electrical). It was built after the [[F-1 (nuclear reactor)]] which was the first reactor to go critical in Europe, and was also built by the Soviet Union.

After World War II, the U.S. military sought other uses for nuclear reactor technology. Research by the Army led to the power stations for Camp Century, Greenland and McMurdo Station, Antarctica [[Army Nuclear Power Program]]. The Air Force Nuclear Bomber project resulted in the [[Molten-Salt Reactor Experiment]]. The U.S. Navy succeeded when they steamed the [[USS Nautilus (SSN-571)|USS ''Nautilus'']] (SSN-571) on nuclear power 17 January 1955.

The first commercial nuclear power station, [[Calder Hall nuclear power station|Calder Hall]] in [[Sellafield]], England was opened in 1956 with an initial capacity of 50 MW (later 200 MW).<ref name=Kragh>{{cite book |last=Kragh|first=Helge |title=Quantum Generations: A History of Physics in the Twentieth Century |url=https://archive.org/details/quantumgeneratio0000krag|url-access=registration|publisher=Princeton University Press |location=Princeton NJ |year=1999 |page=[https://archive.org/details/quantumgeneratio0000krag/page/286 286] |isbn=0-691-09552-3}}</ref><ref name="bbc17oct">{{cite news |url=http://news.bbc.co.uk/onthisday/hi/dates/stories/october/17/newsid_3147000/3147145.stm |title=On This Day: 17&nbsp;October |access-date=9 November 2006 |work=BBC News |date=17 October 1956 |archive-date=27 October 2019 |archive-url=https://web.archive.org/web/20191027163058/http://news.bbc.co.uk/onthisday/hi/dates/stories/october/17/newsid_3147000/3147145.stm |url-status=live }}</ref>

The first portable nuclear reactor "Alco PM-2A" was used to generate electrical power (2 MW) for [[Camp Century]] from 1960 to 1963.<ref>{{cite web | url=http://gombessa.tripod.com/scienceleadstheway/id9.html | title=Science Leads the Way | publisher=Camp Century, Greenland | first=Frank J. | last=Leskovitz | access-date=9 September 2008 | archive-date=29 August 2010 | archive-url=https://web.archive.org/web/20100829201023/http://gombessa.tripod.com/scienceleadstheway/id9.html | url-status=live }}</ref>

=== Table by date ===
{| class="wikitable sortable mw-collapsible"
|+Reactors constructed before 1950
!Name
!Alternate names
!Country
!Location
!Moderator
!Criticality date
|-
|[[Chicago Pile-1]]
|CP-1
|{{Flag|United States|1942}}
|[[University of Chicago]], Illinois
|Graphite
|2 December 1942<ref name="r9742">{{cite book |last=Reed |first=Bruce Cameron |title=Manhattan Project |date=2020 |publisher=Springer International Publishing |isbn=978-3-030-45733-4 |publication-place=Cham |pages=149–169 |chapter=Piles and Secret Cities |doi=10.1007/978-3-030-45734-1_5}}</ref>
|-
|[[Chicago Pile-2]]
|CP-2
|{{Flag|United States|1942}}
|[[Site A]], Illinois
|Graphite
|20 March 1943<ref name="r908">{{cite journal |last=Reed |first=B. Cameron |date=2021 |title=An inter-country comparison of nuclear pile development during World War II |journal=The European Physical Journal H |volume=46 |issue=1 |page=15 |arxiv=2001.09971 |bibcode=2021EPJH...46...15R |doi=10.1140/epjh/s13129-021-00020-x |issn=2102-6459 |doi-access=free}}</ref>
|-
|[[X-10 Graphite Reactor|Oak Ridge Graphite Reactor]]
|X-10, Clinton Pile
|{{Flag|United States|1942}}
|[[Clinton Laboratories]], Tennessee
|Graphite
|4 November 1943<ref name="r9083">{{cite journal |last=Reed |first=B. Cameron |date=2021 |title=An inter-country comparison of nuclear pile development during World War II |journal=The European Physical Journal H |volume=46 |issue=1 |page=15 |arxiv=2001.09971 |bibcode=2021EPJH...46...15R |doi=10.1140/epjh/s13129-021-00020-x |issn=2102-6459 |doi-access=free}}</ref>
|-
|[[305 Test Pile]]<ref name="b3802">{{cite report |title=Nuclear reactors built, being built, or planned 1993 |date=1993-08-01 |publisher=Office of Scientific and Technical Information (OSTI) |doi=10.2172/10141005 |page= |doi-access=free|osti=10141005 }}</ref>
|
|{{Flag|United States|1942}}
|[[Hanford Site]], Washington
|Graphite
|March 1944<ref name="r9084">{{cite journal |last=Reed |first=B. Cameron |date=2021 |title=An inter-country comparison of nuclear pile development during World War II |journal=The European Physical Journal H |volume=46 |issue=1 |page=15 |arxiv=2001.09971 |bibcode=2021EPJH...46...15R |doi=10.1140/epjh/s13129-021-00020-x |issn=2102-6459 |doi-access=free}}</ref>{{When|date=January 2025|reason=The whole pile is very obscure I'm not sure if anyone can find this information but would be nice}}
|-
|[[Chicago Pile-3]]
|CP-3
|{{Flag|United States|1942}}
|[[Site A]], Illinois
|Heavy water
|15 May 1944<ref name="t0242">{{cite web |title=Manhattan Project: Places > Metallurgical Laboratory > CP-2 and CP-3 |url=https://www.osti.gov/opennet/manhattan-project-history/Places/MetLab/cp2-3.html |access-date=2024-12-25 |website=OSTI.GOV}}</ref>
|-
|[[LOPO|Los Alamos LOPO Reactor]]<ref name="b380">{{cite report |title=Nuclear reactors built, being built, or planned 1993 |date=1993-08-01 |publisher=Office of Scientific and Technical Information (OSTI) |doi=10.2172/10141005 |page= |doi-access=free|osti=10141005 }}</ref>
|LOPO
|{{Flag|United States|1942}}
|[[Project Y|Los Alamos Laboratory]], New Mexico
|Light water
|9 May 1944<ref name="o365">{{cite web |date=1920-06-03 |title=Timeline |url=https://ahf.nuclearmuseum.org/ahf/nuc-history/timeline/ |access-date=2024-11-07 |website=Nuclear Museum}}</ref>
|-
|[[B Reactor]]
|
|{{Flag|United States|1942}}
|[[Hanford Site]], Washington
|Graphite
|26 September 1944<ref name="r9082">{{cite journal |last=Reed |first=B. Cameron |date=2021 |title=An inter-country comparison of nuclear pile development during World War II |journal=The European Physical Journal H |volume=46 |issue=1 |page=15 |arxiv=2001.09971 |bibcode=2021EPJH...46...15R |doi=10.1140/epjh/s13129-021-00020-x |issn=2102-6459 |doi-access=free}}</ref>
|-
|[[Project Y#Water boiler|Los Alamos Water Boiler]]
|HYPO
|{{Flag|United States|1942}}
|[[Project Y|Los Alamos Laboratory]], New Mexico
|Light water
|December 1944<ref name="o363">{{cite report |url=https://www.osti.gov/servlets/purl/1133322 |title=Discussion Regarding Aqueous Homogeneous Reactor (AHR) Benchmarks |last1=Klein |first1=Steven |last2=Kimpland |first2=Robert |date=2014-05-28 |doi=10.2172/1133322 |page= |access-date=2024-12-30 |doi-access=free}}</ref>{{When|date=January 2025|reason=Not sure if available information but would be nice to narrow the day}}
|-
|D Reactor
|
|{{Flag|United States|1942}}
|[[Hanford Site]], Washington
|Graphite
|December 1944<ref name="c166">{{cite web |date=1994-09-30 |title=Plutonium: The First 50 Years |url=https://sgp.fas.org/othergov/doe/pu50yc.html |access-date=2024-12-24 |website=FAS Project on Government Secrecy (1991-2021)}}</ref>
|-
|[[Dragon (pulsed nuclear reactor)|Dragon]]
|
|{{Flag|United States|1942}}
|[[Project Y|Los Alamos Laboratory]], New Mexico
|None (fast)
|20 January 1945<ref name="e6442">{{cite journal |last1=Kimpland |first1=Robert |last2=Grove |first2=Travis |last3=Jaegers |first3=Peter |last4=Malenfant |first4=Richard |last5=Myers |first5=William |date=2021-12-03 |title=Critical Assemblies: Dragon Burst Assembly and Solution Assemblies |journal=Nuclear Technology |volume=207 |issue=sup1 |pages=S81–S99 |arxiv=2103.05780 |bibcode=2021NucTe.207S..81K |doi=10.1080/00295450.2021.1927626 |issn=0029-5450 |doi-access=free}}</ref>
|-
|F Reactor
|
|{{Flag|United States|1942}}
|[[Hanford Site]], Washington
|Graphite
|February 1945<ref name="c166" />
|-
| colspan="5" |''[[Trinity test|Trinity]], first US nuclear test''
|''16 July 1945''
|-
|[[ZEEP|Zero Energy Experimental Pile]]
|ZEEP
|{{Flag|Canada}}
|[[Chalk River Laboratories]], Ontario
|Heavy water
|5 September 1945<ref name="zeep-cstm2">{{cite web |title=ZEEP -- Canada's First Nuclear Reactor |url=http://www.sciencetech.technomuses.ca/english/whatson/zeep.cfm |archiveurl=https://web.archive.org/web/20140306233719/http://www.sciencetech.technomuses.ca/english/whatson/zeep.cfm |archivedate=6 March 2014 |publisher=Canada Science and Technology Museum}}</ref>
|-
|[[Clementine (nuclear reactor)|Los Alamos Fast Reactor]]
|Clementine
|{{Flag|United States|1942}}
|[[Project Y|Los Alamos Laboratory]], New Mexico
|None (fast)
|19 November 1946<ref name="j8012">{{cite journal |last1=Patenaude |first1=Hannah K. |last2=Freibert |first2=Franz J. |date=2023-03-09 |title=Oh, My Darling Clementine: A Detailed History and Data Repository of the Los Alamos Plutonium Fast Reactor |journal=Nuclear Technology |publisher=Informa UK Limited |volume=209 |issue=7 |pages=963–1007 |bibcode=2023NucTe.209..963P |doi=10.1080/00295450.2023.2176686 |issn=0029-5450 |doi-access=free}}</ref>
|-
|[[F-1 (nuclear reactor)|F-1]]
|
|{{Flag|Soviet Union}}
|[[Kurchatov Institute|Laboratory No. 2]], Moscow
|Graphite
|25 December 1946
|-
|[[NRX|National Research Experimental]]
|NRX
|{{Flag|Canada}}
|[[Chalk River Laboratories]], Ontario
|Heavy water
|22 July 1947<ref name="y105">{{cite book |last=Hurst |first=D.G. |url=https://books.google.com/books?id=3uz0AwAAQBAJ |title=Canada Enters the Nuclear Age: A Technical History of Atomic Energy of Canada Limited as Seen from Its Research Laboratories |publisher=McGill-Queen's University Press |year=1997 |isbn=978-0-7735-6653-8 |page=45 |access-date=2024-12-31}}</ref>
|-
|[[GLEEP|Graphite Low Energy Experimental Pile]]
|GLEEP
|{{Flag|United Kingdom}}
|[[Atomic Energy Research Establishment]], Oxfordshire
|Graphite
|15 August 1947<ref>{{Cite book |last=Hill |first=C |title=An Atomic Empire: A Technical History of the Rise and Fall of the British Atomic Energy Programme |date=2013 |publisher=Imperial College Press |isbn=978-1-908977-41-0}}</ref>
|-
|Reactor A
|
|{{Flag|Soviet Union}}
|[[Mayak Production Association]], Chelyabinsk Oblast
|Graphite
|10 June 1948<ref name="s400">{{cite journal |last=Diakov |first=Anatoli |date=2011-04-25 |title=The History of Plutonium Production in Russia |journal=Science & Global Security |volume=19 |issue=1 |pages=28–45 |bibcode=2011S&GS...19...28D |doi=10.1080/08929882.2011.566459 |issn=0892-9882}}</ref>
|-
|[[BEPO (nuclear reactor)|British Experimental Pile Operation]]
|BEPO
|{{Flag|United Kingdom}}
|[[Atomic Energy Research Establishment]], Oxfordshire
|Graphite
|3 July 1948<ref name="l121">{{cite web |date=2023-07-03 |title=Magnox BEPO reactor 75th Anniversary |url=https://www.gov.uk/government/news/magnox-bepo-reactor-75th-anniversary |access-date=2025-01-13 |website=GOV.UK}}</ref>
|-
|[[Zoé (reactor)|Eau Lourde-1]] (Heavy Water-1)
|EL-1, Zoé
|{{Flag|France|1949}}
|[[Fort de Châtillon]], Paris
|Heavy water
|15 December 1948<ref name="ic12">{{cite web |title=Irène and Frédéric Joliot-Curie |url=http://www.curie.fr/fondation/musee/irene-frederic-joliot-curie.cfm/lang/_gb.htm |url-status=dead |archive-url=https://web.archive.org/web/20100603032613/http://www.curie.fr/fondation/musee/irene-frederic-joliot-curie.cfm/lang/_gb.htm |archive-date=2010-06-03 |access-date=26 April 2010 |publisher=Institut Curie}}</ref>
|-
|[[Physical Boiler on Fast Neutrons]]
|FKBN
|{{Flag|Soviet Union}}
|[[All-Russian Scientific Research Institute of Experimental Physics|Design Bureau No. 11]], Sarov
|None (fast)
|1 February 1949<ref name="k264">{{cite web |title=ФКБН / Сводный указатель объектов / Атомный проект СССР // Электронная библиотека /// История Росатома |url=https://elib.biblioatom.ru/soviet-atomic-program/objects/fizicheskiy_kotel_na_byistryih_neytronah@13272/ |access-date=2025-01-10 |website=Электронная библиотека /// История Росатома |language=ru}}</ref>
|-
|[[TVR (nuclear reactor)|TVR]]
|TVR
|{{Flag|Soviet Union}}
|[[Institute for Theoretical and Experimental Physics|Laboratory No. 3]], Moscow
|Heavy water
|April 1949<ref name="b940">{{cite journal |last1=Loffe |first1=B. L. |last2=Shvedov |first2=O. V. |date=1999 |title=Heavy water reactors and nuclear power plants in the USSR and Russia: Past, present, and future |journal=Atomic Energy |volume=86 |issue=4 |pages=295–304 |doi=10.1007/BF02673145 |issn=1063-4258}}</ref>
|-
| colspan="5" |''[[RDS-1]], first Soviet nuclear test''
|''29 August 1949''
|-
|H Reactor
|
|{{Flag|United States|1942}}
|[[Hanford Site]], Washington
|Graphite
|October 1949<ref name="c166" />
|}

=== Table by country ===
{| class="wikitable sortable mw-collapsible"
|+First nations to operate a nuclear reactor
!Country
!First reactor
!Criticality date
!First grid-connected reactor
!Connection date
|-
|{{Flag|United States|1942}}
|[[Chicago Pile-1|CP-1]]
|{{Date table sorting|2 December 1942}}<ref name="r974">{{cite book |last=Reed |first=Bruce Cameron |title=Manhattan Project |date=2020 |publisher=Springer International Publishing |isbn=978-3-030-45733-4 |publication-place=Cham |pages=149–169 |chapter=Piles and Secret Cities |doi=10.1007/978-3-030-45734-1_5}}</ref>
|[[Shippingport Atomic Power Station]]
|{{Date table sorting|18 December 1957}}<ref name="s016">{{cite web |date=1955-05-01 |title=Shippingport |url=https://world-nuclear.org/nuclear-reactor-database/details/SHIPPINGPORT |access-date=2025-01-04 |website=World Nuclear Association}}</ref>
|-
|{{Flag|Canada}}
|[[ZEEP]]
|{{Date table sorting|5 September 1945}}<ref name="zeep-cstm">{{cite web |title=ZEEP -- Canada's First Nuclear Reactor |url=http://www.sciencetech.technomuses.ca/english/whatson/zeep.cfm |archiveurl=https://web.archive.org/web/20140306233719/http://www.sciencetech.technomuses.ca/english/whatson/zeep.cfm |archivedate=6 March 2014 |publisher=Canada Science and Technology Museum}}</ref>
|[[Nuclear Power Demonstration]]
|{{Date table sorting|4 June 1962}}<ref name="i361">{{cite web |date=1958-01-01 |title=Rolphton NPD |url=https://world-nuclear.org/nuclear-reactor-database/details/Rolphton-NPD |access-date=2025-01-04 |website=World Nuclear Association}}</ref>
|-
|{{Flag|Soviet Union}}
|[[F-1 (nuclear reactor)|F-1]]
|{{Date table sorting|25 December 1946}}<ref>{{cite web |last=Vakhroucheva |first=Elizaveta |title=Division of System Analysis Elektronika Information and Computer Complex Engineering and Production Division |url=http://www.nti.org/db/nisprofs/russia/reactor/research/with/kurchato.htm#f1 |url-status=dead |archive-url=https://web.archive.org/web/20090115212712/http://www.nti.org/db/nisprofs/russia/reactor/research/with/kurchato.htm#f1 |archive-date=15 January 2009 |accessdate=25 December 2010 |work=[[Kurchatov Institute]] |publisher=NTI}}</ref>
|[[Obninsk Nuclear Power Plant]]
|{{Date table sorting|27 June 1954}}<ref name="n584">{{cite web |date=1951-01-01 |title=APS 1 Obninsk |url=https://world-nuclear.org/nuclear-reactor-database/details/APS-1-Obninsk |access-date=2025-01-04 |website=World Nuclear Association}}</ref>
|-
|{{Flag|United Kingdom}}
|[[GLEEP]]
|{{Date table sorting|15 August 1947}}<ref>{{Cite book |last=Hill |first=C |title=An Atomic Empire: A Technical History of the Rise and Fall of the British Atomic Energy Programme |date=2013 |publisher=Imperial College Press |isbn=978-1-908977-41-0}}</ref>
|[[Calder Hall nuclear power station]]
|{{Date table sorting|27 August 1956}}<ref name="x809">{{cite web |date=1953-08-01 |title=Calder Hall 1 |url=https://world-nuclear.org/nuclear-reactor-database/details/Calder-Hall-1 |access-date=2025-01-04 |website=World Nuclear Association}}</ref>
|-
|{{Flag|France|1949}}
|[[Zoé (reactor)|EL-1 (Zoé)]] 
|{{Date table sorting|15 December 1948}}<ref name="ic1">{{cite web |title=Irène and Frédéric Joliot-Curie |url=http://www.curie.fr/fondation/musee/irene-frederic-joliot-curie.cfm/lang/_gb.htm |url-status=dead |archive-url=https://web.archive.org/web/20100603032613/http://www.curie.fr/fondation/musee/irene-frederic-joliot-curie.cfm/lang/_gb.htm |archive-date=2010-06-03 |access-date=26 April 2010 |publisher=Institut Curie}}</ref>
|[[Marcoule Nuclear Site]]
|{{Date table sorting|22 April 1959}}<ref name="j266">{{cite web |date=1955-03-01 |title=G 2 (Marcoule) |url=https://world-nuclear.org/nuclear-reactor-database/details/G-2-(Marcoule) |access-date=2025-01-04 |website=World Nuclear Association}}</ref>
|-
|{{Flag|Norway}}{{NoteTag|JEEP was constructed jointly by the Norwegian [[Royal Norwegian Council for Scientific and Industrial Research|NTNF]] and the Dutch {{ill|Foundation for Fundamental Research on Matter|lt=FOM|nl|FOM}}}}
|[[JEEP (nuclear reactor)|JEEP]]
|{{Date table sorting|30 July 1951}}<ref name="r938">{{cite web |last=Splunter |first=J.M. van. |date=1994 |title=Love at first sight. Co-operation between the Netherlands and Norway on the peaceful use of atomic energy, 1950-1960 |url=https://inis.iaea.org/search/search.aspx?orig_q=RN:26038487 |access-date=2025-01-04 |website=INIS}}</ref>
|None constructed
|n/a
|-
|{{Flag|Sweden}}
|[[R1 (nuclear reactor)|R1]]
|{{Date table sorting|13 July 1954}}<ref name="c539">{{cite web |last=Blomstrand |first=Edward |date=2005-02-01 |title=Swedish nuclear power. A review of the legislation in the nuclear energy field from the second world war til the new millennium; Svensk kaernenergi. En expose oever lagstiftningen paa kaernenergiomraadet fraan andra vaerldskriget till millennieskiftet |url=https://www.osti.gov/etdeweb/biblio/20637474 |access-date=2025-01-05 |website=OSTI.GOV}}</ref>
|[[Ågesta Nuclear Plant]]
|{{Date table sorting|1 May 1964}}<ref name="g768">{{cite web |date=1957-12-01 |title=Agesta |url=https://world-nuclear.org/nuclear-reactor-database/details/Agesta |access-date=2025-01-04 |website=World Nuclear Association}}</ref>
|-
|{{Flag|Belgium|1956}}
|{{Interlanguage link|BR1 (nuclear reactor)|lt=BR1|nl|BR1|fr|SCK_CEN#BR-1}}
|{{Date table sorting|11 May 1956}}<ref name="a063">{{cite web |last=Domain |first=Research |date=2016-04-25 |title=Belgian Reactor 1 / Research facilities / Science Platform |url=http://science.sckcen.be/en/Facilities/BR1 |url-status=dead |archive-url=https://web.archive.org/web/20160625034245/http://science.sckcen.be/en/Facilities/BR1 |archive-date=2016-06-25 |access-date=2025-01-06 |website=science.sckcen.be}}</ref>
|{{Interlanguage link|BR3 (nuclear reactor)|lt=BR3|nl|BR3|fr|SCK_CEN#BR-3}}
|{{Date table sorting|10 October 1962}}<ref name="t184">{{cite web |date=1957-11-01 |title=BR-3 |url=https://world-nuclear.org/nuclear-reactor-database/details/BR-3 |access-date=2025-01-06 |website=World Nuclear Association}}</ref>
|-
|{{Flag|India}}
|[[Apsara (nuclear reactor)|Apsara]]
|{{Date table sorting|4 August 1956}}'''<ref>{{cite web |title=Apsara Research Reactor |url=http://www.nti.org/facilities/818/ |url-status=dead |archive-url=https://web.archive.org/web/20150419042039/http://www.nti.org/facilities/818/ |archive-date=19 April 2015 |access-date=12 April 2015}}</ref>'''
|[[Tarapur Atomic Power Station]]
|{{Date table sorting|1 April 1969}}<ref name="c800">{{cite web |date=1964-10-01 |title=Tarapur 1 |url=https://world-nuclear.org/nuclear-reactor-database/details/Tarapur-1 |access-date=2025-01-04 |website=World Nuclear Association}}</ref>
|-
|{{Flag|Japan}}
|{{Interlanguage link|JRR-1|ja|JRR-1}}
|27 August 1957
|[[Tōkai Nuclear Power Plant]]
|25 July 1966
|-
|{{Flag|West Germany}}
|{{Interlanguage link|FRM-I|de|Forschungsreaktor_München}}
|{{Date table sorting|31 October 1957}}<ref name="t885">{{cite book |last=Trischler |first=Helmuth |title=Politik und Kultur im föderativen Staat 1949 bis 1973 |date=2004-12-31 |publisher=OLDENBOURG WISSENSCHAFTSVERLAG |isbn=978-3-486-56596-6 |page=156 |chapter=Nationales Innovationssystem und regionale Innovationspolitik |doi=10.1524/9783486708646.117}}</ref>
|[[Kahl Nuclear Power Plant]]
|{{Date table sorting|17 June 1961}}<ref name="u093">{{cite web |date=1958-07-01 |title=VAK Kahl |url=https://world-nuclear.org/nuclear-reactor-database/details/VAK-Kahl |access-date=2025-01-04 |website=World Nuclear Association}}</ref>
|-
|{{Flag|East Germany}}
|{{Interlanguage link|RFR (nuclear reactor)|de|Rossendorfer_Forschungsreaktor|lt=RFR}}
|16 December 1957<ref name="s1462">{{cite web |date=1955-04-18 |title=Die Geschichte des HZDR im Überblick |url=https://www.hzdr.de/db/Cms?pOid=26670&pNid=1826 |access-date=2025-05-10 |website=Helmholtz-Zentrum Dresden-Rossendorf, HZDR}}</ref>
|[[Rheinsberg Nuclear Power Plant]]
|6 May 1966<ref name="e389">{{cite web |date=1960-01-01 |title=Rheinsberg |url=https://world-nuclear.org/nuclear-reactor-database/details/RHEINSBERG |access-date=2025-05-10 |website=World Nuclear Association}}</ref>
|-
|{{Flag|China}}
|[[HWRR]]
|{{Date table sorting|27 September 1958}}<ref name="e655">{{cite journal |last=Frank |first=Lewis A. |date=1966 |title=Nuclear Weapons Development in China |journal=Bulletin of the Atomic Scientists |volume=22 |issue=1 |pages=12–15 |bibcode=1966BuAtS..22a..12F |doi=10.1080/00963402.1966.11454882 |issn=0096-3402}}</ref>
|[[Qinshan Nuclear Power Plant]]
|{{Date table sorting|15 December 1991}}<ref name="y728">{{cite web |date=1985-03-20 |title=Qinshan 1 |url=https://world-nuclear.org/nuclear-reactor-database/details/Qinshan-1 |access-date=2025-01-04 |website=World Nuclear Association}}</ref>
|-
|{{Flag|Italy}}
|{{Interlanguage link|ISPRA-1|it|ISPRA-1}}
|{{Date table sorting|20 November 1959}}<ref>{{cite web |title=Scorie a riposo. ISPRA-1, il primo reattore nucleare italiano {{!}} Il Bo Live UniPD |url=https://ilbolive.unipd.it/it/news/societa/scorie-riposo-ispra1-primo-reattore-nucleare |website=ilbolive.unipd.it |access-date=25 April 2025 |language=it |date=18 July 2022}}</ref>
|[[Latina Nuclear Power Plant]]
|{{Date table sorting|May 1963}}
|}
[[File:HPR1000, reactor coolant system.png|thumb|Primary coolant system showing [[reactor pressure vessel]] (red), [[Steam generator (nuclear power)|steam generators]] (purple), [[pressurizer]] (blue), and pumps (green) in the three coolant loop [[Hualong One]] [[pressurized water reactor]] design]]