Editing Nuclear chain reaction (section)

{{Short description|When one nuclear reaction causes more}}
{{refimprove|date=October 2024}}
[[Image:Fission chain reaction.svg|300px|thumb|A possible [[nuclear fission]] chain reaction: <br/> 
1) A [[uranium-235]] atom absorbs a [[neutron]] and fissions into two [[Nuclear fission product|fission fragments]], releasing three new neutrons and a large amount of [[binding energy]]. <br/> 
2) One of those neutrons is absorbed by an atom of [[uranium-238]], and does not continue the reaction. Another neutron leaves the system without being absorbed. However, one neutron does collide with an atom of uranium-235, which then fissions and releases two neutrons and more binding energy. <br/> 
3) Both of those neutrons collide with uranium-235 atoms, each of which fissions and releases a few neutrons, which can then continue the reaction.]]

In [[nuclear physics]], a '''nuclear chain reaction''' occurs when one single [[nuclear reaction]] causes an average of one or more subsequent nuclear reactions, thus leading to the possibility of a [[Positive feedback|self-propagating series]] or "positive feedback loop" of these reactions. The specific nuclear reaction may be the [[Nuclear fission|fission]] of heavy [[isotope]]s (e.g., [[uranium-235]], <sup>235</sup>U). A nuclear chain reaction releases several million times more energy per reaction than any [[chemical reaction]].