Editing Nuclear reactor (section)

====By moderator material====
Used by thermal reactors:
* [[Graphite-moderated reactor]]s
** Mostly early reactors such as the Chicago pile, Obninsk am 1, Windscale piles, RBMK, Magnox, and others such as AGR use graphite as a moderator.
* Water moderated reactors
**[[Heavy-water reactor]]s (Used in Canada,<ref name="hyperphysics">{{cite web|last1=Nave|first1=R|title=Light Water Nuclear Reactors|url=http://hyperphysics.phy-astr.gsu.edu/hbase/NucEne/ligwat.html|website=Hyperphysics|publisher=Georgia State University|access-date=5 March 2018|archive-date=3 December 2017|archive-url=https://web.archive.org/web/20171203053318/http://hyperphysics.phy-astr.gsu.edu/hbase/NucEne/ligwat.html|url-status=live}}</ref> India, Argentina, China, Pakistan, Romania and South Korea).<ref>{{Cite book|last=Joyce|first=Malcolm|date=2018|title=Nuclear Engineering|publisher=Elsevier|chapter=10.6|doi=10.1016/c2015-0-05557-5|isbn=9780081009628}}</ref>
** [[Light-water reactor|Light-water-moderated reactors]] (LWRs). Light-water reactors (the most common type of thermal reactor) use ordinary water to moderate and cool the reactors.<ref name="hyperphysics"/> Because the light hydrogen isotope is a slight neutron poison, these reactors need artificially enriched fuels. When at [[operating temperature]], if the temperature of the water increases, its density drops, and fewer neutrons passing through it are slowed enough to trigger further reactions. That [[negative feedback]] stabilizes the reaction rate. Graphite and heavy-water reactors tend to be more thoroughly thermalized than light water reactors. Due to the extra thermalization, and the absence of the light hydrogen poisoning effects these types can use [[natural uranium]]/unenriched fuel.
* Light-element-moderated reactors.
** [[Molten-salt reactor]]s (MSRs) are moderated by light elements such as lithium or beryllium, which are constituents of the coolant/fuel matrix salts [[Lithium fluoride|"LiF"]] and [[Beryllium fluoride|"BeF<sub>2</sub>]]", [[Lithium chloride|"LiCl"]] and [[Beryllium chloride|"BeCl<sub>2</sub>]]" and other light element containing salts can all cause a moderating effect.
** [[Liquid metal cooled reactor]]s, such as those whose coolant is a mixture of lead and bismuth, may use BeO as a moderator.
* [[Organic nuclear reactor|Organically moderated reactors]] (OMR) use [[biphenyl]] and [[terphenyl]] as moderator and coolant.