Editing United States naval reactors (section)

==Power plants==
Current U.S. naval reactors are all pressurized water reactors,<ref>{{Cite web|title=Fact Sheet on U.S. Nuclear Powered Warship (NPW) Safety|url=https://www.mofa.go.jp/region/n-america/us/security/fact0604.pdf}}</ref> which are identical to PWR commercial reactors producing electricity, except that:

* They have a high power density in a small volume and run either on low-enriched uranium (as do some French and Chinese submarines) or on highly [[enriched uranium]] (>20% U-235, current U.S. submarines use fuel enriched to at least 93%)<ref>{{cite journal | author = Morten Bremer Maerli | title = Components of Naval Nuclear Fuel Transparency | publisher = Norwegian Institute of International Affairs | date = 1 January 2002 | url = http://www.nato.int/acad/fellow/99-01/maerli.pdf | access-date = 2007-02-07 }}</ref>
* They have long core lives, so that refueling is needed only after 10 or more years, and new cores are designed to last 25&nbsp;years in carriers and 10–33&nbsp;years in submarines,
* The design enables a compact pressure vessel while maintaining safety.{{clarify|date=September 2015}}
Long core life is enabled by high uranium enrichment and by incorporating a "[[Nuclear poison|burnable neutron poison]]", which is progressively depleted as [[Nuclear poison|non-burnable poison]]s like [[fission product]]s and [[actinide]]s accumulate.  The loss of burnable poison counterbalances the creation of non-burnable poisons and result in stable long term [[fuel efficiency]].

Long-term integrity of the compact reactor pressure vessel is maintained by providing an internal neutron shield. (This is in contrast to early Soviet civil PWR designs where embrittlement occurs due to neutron bombardment of a very narrow pressure vessel.)

Reactor sizes range up to ~500&nbsp;[[MWt]] (about 165&nbsp;MWe) in the larger submarines and surface ships. The French {{sclass|Rubis|submarine|2}}s have a 48&nbsp;MW reactor that needs no refueling for 30&nbsp;years.

The nuclear navies of the United States, the United Kingdom, and the Russian Federation rely on steam turbine propulsion. Those of the French and Chinese use the turbine to generate electricity for propulsion. Most Russian submarines as well as all U.S. surface ships since ''Enterprise'' are powered by two or more reactors. U.S., British, French, Chinese and Indian submarines are powered by one.

Decommissioning nuclear-powered submarines has become a major task for American and Russian navies.<ref>{{Cite web|title=Nuclear Submarine Dismantlement {{!}} NTI|url=https://www.nti.org/analysis/articles/nuclear-submarine-dismantlement/|access-date=2021-04-25|website=nti.org|date=31 July 2001 }}</ref> After defuelling, U.S. practice is to cut the reactor section from the vessel for disposal in shallow land burial as low-level waste (see the [[Ship-Submarine Recycling Program]]).