Editing Nuclear power (section)

===First power generation===
The first organization to develop practical nuclear power was the [[United States Navy|U.S. Navy]], with the [[S1W reactor]] for the purpose of propelling [[submarine]]s and [[aircraft carrier]]s. The first nuclear-powered submarine, {{USS|Nautilus|SSN-571|6}}, was put to sea in January 1954.<ref name="iaeapdf" /><ref>{{cite web |url=http://www.ne.anl.gov/About/reactors/lwr3.shtml#fragment-2 |title=STR (Submarine Thermal Reactor) in "Reactors Designed by Argonne National Laboratory: Light Water Reactor Technology Development" |publisher=U.S. Department of Energy, Argonne National Laboratory |year=2012 |access-date=2012-07-25 |archive-date=2012-06-22 |archive-url=https://web.archive.org/web/20120622185310/http://www.ne.anl.gov/About/reactors/lwr3.shtml#fragment-2 |url-status=live }}</ref> The S1W reactor was a [[pressurized water reactor]]. This design was chosen because it was simpler, more compact, and easier to operate compared to alternative designs, thus more suitable to be used in submarines. This decision would result in the PWR being the reactor of choice also for power generation, thus having a lasting impact on the civilian electricity market in the years to come.<ref>{{cite book|last=Rockwell|first=Theodore|title=The Rickover Effect|publisher=Naval Institute Press|year=1992|page=162|isbn=978-1-55750-702-0}}</ref>

On June 27, 1954, the [[Obninsk Nuclear Power Plant]] in the [[USSR]] became the world's first nuclear power plant to generate electricity for a [[power grid]], producing around 5 megawatts of electric power.<ref name="IAEANews">{{cite web |url=http://www.iaea.org/NewsCenter/News/2004/obninsk.html |title=From Obninsk Beyond: Nuclear Power Conference Looks to Future |website=[[International Atomic Energy Agency]] |access-date=2006-06-27 |date=2004-06-23 |archive-date=2006-11-15 |archive-url=https://web.archive.org/web/20061115165641/http://www.iaea.org/NewsCenter/News/2004/obninsk.html |url-status=live }}</ref> The world's first commercial nuclear power station, [[Calder Hall nuclear power station|Calder Hall]] at Windscale, England was connected to the national power grid on 27 August 1956. In common with a number of other [[generation I reactor]]s, the plant had the dual purpose of producing [[electricity]] and [[plutonium-239]], the latter for the nascent [[Nuclear weapons and the United Kingdom|nuclear weapons program in Britain]].<ref>{{cite book |last1=Hill |first1=C. N. |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=978-1-908977-43-4 |location=London, England}}</ref>