Editing Breeder reactor (section)

=== Conversion ratio ===
One measure of a reactor's performance is the "conversion ratio", defined as the ratio of new fissile atoms produced to fissile atoms consumed. All proposed nuclear reactors except specially designed and operated actinide burners<ref name="Hoffman">{{cite web |title=Preliminary Core Design Studies for the Advanced Burner Reactor over a Wide Range of Conversion Ratios |id=ANL-AFCI-177 |website=Argonne National Laboratory |author=E. A. Hoffman |author2=W. S. Yang |author3=R. N. Hill |url=https://publications.anl.gov/anlpubs/2008/05/61507.pdf}}</ref> experience some degree of conversion. As long as there is any amount of a fertile material within the [[neutron flux]] of the reactor, some new fissile material is always created. When the conversion ratio is greater than 1, it is often called the "breeding ratio".

For example, commonly used light water reactors have a conversion ratio of approximately 0.6. [[Pressurized heavy-water reactor|Pressurized heavy-water reactors]] running on natural uranium have a conversion ratio of 0.8.<ref>{{cite web |last=Kadak |first=Prof. Andrew C. |title=Lecture 4, Fuel Depletion & Related Effects |work=Operational Reactor Safety 22.091/22.903 |publisher=Hemisphere, as referenced by MIT |page=Table 6–1, "Average Conversion or Breeding Ratios for Reference Reactor Systems" |url=http://www.learningace.com/doc/3103775/a22b70ccd4d6c2b95d5cc687c2e09c06/mit22_091s08_lec04 |access-date=24 December 2012 |url-status=dead |archive-url=https://web.archive.org/web/20151017114605/http://www.learningace.com/doc/3103775/a22b70ccd4d6c2b95d5cc687c2e09c06/mit22_091s08_lec04 |archive-date=17 October 2015}}</ref> In a breeder reactor, the conversion ratio is higher than 1. "Break-even" is achieved when the conversion ratio reaches 1.0 and the reactor produces as much fissile material as it uses.