Editing S1G reactor (section)

== History ==
This [[nuclear reactor]] was constructed by General Electric as a prototype for the [[USS Seawolf (SSN-575)|USS ''Seawolf'' (SSN-575)]] submarine.  It was a [[liquid metal cooled reactor]] using pure [[sodium]] to cool the core instead of water, because the higher temperature of liquid sodium (compared to pressurized water) enabled the production of more superheated [[steam]] in the [[Steam generator (nuclear power)|steam generators]].  This resulted in a more efficient thermal cycle, yielding more [[Horsepower#Shaft horsepower|shaft horsepower]] for a given reactor size.  The reactor design had problems because of limited [[operating temperature]] constraints.  The major disadvantage of this concept was the ignition of sodium when exposed to air. The reactor core was [[beryllium]]-[[neutron moderator|moderated]].<ref>{{Cite web| title=Marine Nuclear Power: 1939 – 2018 - Part 2A: United States - Submarines | author=Peter Lobner | date=July 2018 | url=https://lynceans.org/wp-content/uploads/2020/02/Marine-Nuclear-Power-1939-2018_Part-2A_USA_submarines.pdf | archive-url=https://web.archive.org/web/20200924063831/https://lynceans.org/wp-content/uploads/2020/02/Marine-Nuclear-Power-1939-2018_Part-2A_USA_submarines.pdf | archive-date=2020-09-24}}</ref><ref>{{cite web | url=https://books.google.com/books?id=9TRUAAAAMAAJ&dq=s2g+reactor+beryllium&pg=SA25-PA6 | title=Naval Reactors Physics Handbook: The physics of intermediate spectrum ractors, edited by J.R. Stehn | date=1964 }}</ref>

S1G was used for testing and training.  Eventually a sodium leak resulted in a fire, and the facility was shut down.  In the meantime, the [[S1W reactor|S1W]] and [[S2W reactor|S2W]] [[pressurized water reactor]]s, conceived for the [[USS Nautilus (SSN-571)|USS ''Nautilus'' (SSN-571)]], had demonstrated their superior reliability.  The S1G reactor facility and its [[Horton sphere]] were later reused for the [[D1G reactor|D1G]] prototype destroyer reactor.