Editing Tritium (section)

=== Deuterium ===
{{See also|Heavy water#Tritium production}}
Tritium is also produced in [[Pressurized heavy-water reactor|heavy water-moderated reactor]]s whenever a [[deuterium]] nucleus captures a neutron. This reaction has a small absorption [[cross section (physics)|cross section]], making [[heavy water]] a good [[neutron moderator]], and relatively little tritium is produced. Even so, cleaning tritium from the moderator may be desirable after several years to reduce the risk of its escaping to the environment. [[Ontario Power Generation]]'s "Tritium Removal Facility" is capable of processing up to {{convert|2500|t}} of heavy water a year, and it separates out about {{convert|2.5|kg|abbr=on}} of tritium, making it available for other uses.<ref>
{{cite web
 | last = Whitlock  | first= Jeremy 
 | title = Section D: Safety and Liability – How does Ontario Power Generation manage tritium production in its CANDU moderators? 
 | publisher = Canadian Nuclear FAQ
 | url = http://www.nuclearfaq.ca/cnf_sectionD.htm#x5
 | access-date = 19 September 2010
}}
</ref>
[[CANDU reactor]]s typically produce {{convert|130|g}} of tritium per year, which is recovered at the Darlington Tritium Recovery Facility (DTRF) attached to the 3,512 MW{{sub|electric}} [[Darlington Nuclear Generating Station]] in Ontario. The total production at DTRF between 1989 and 2011 was {{convert|42.5|kg}} – with an activity of {{convert|409|MCi}}: an average of about {{convert|2|kg}} per year.<ref>{{cite journal |title=Tritium supply and use: a key issue for the development of nuclear fusion energy |first1= Richard J. |last1=Pearson |first2=Armando B. |last2=Antoniazzi |first3=William J. |last3=Nuttall |doi=10.1016/j.fusengdes.2018.04.090 |doi-access=free |journal=[[Fusion Engineering and Design]] |volume=136 |date=November 2018 |pages=1140–1148 |publisher=Elsevier|bibcode= 2018FusED.136.1140P }}</ref>

Deuterium's absorption cross section for [[thermal neutron]]s is about 0.52 [[barn (unit)|millibarn]], whereas that of [[oxygen-16]] ({{sup|16}}O) is about 0.19 millibarn and that of [[oxygen-17]] ({{sup|17}}O) is about 240 millibarns. While {{sup|16}}O is by far the most common [[isotope of oxygen]] in both natural oxygen and heavy water; depending on the method of [[isotope separation]], heavy water may be slightly richer in {{sup|17}}O and [[oxygen-18|{{sup|18}}O]]. Due to both [[neutron capture]] and (n,[[alpha particle|α]]) reactions (the latter of which produce [[carbon-14|{{sup|14}}C]], an undesirable long-lived beta emitter, from {{sup|17}}O) they are net "neutron consumers" and are thus undesirable in a moderator of a natural uranium reactor which needs to keep neutron absorption outside the fuel as low as feasible. Some facilities that remove tritium also remove (or at least reduce the content of) {{sup|17}}O and {{sup|18}}O, which can – at least in principle – be used for [[isotope labeling]].

India, which also has a large fleet of [[pressurized heavy water reactor]]s (initially CANDU technology but since indigenized and further developed [[IPHWR]] technology), also removes at least some of the tritium produced in the moderator/coolant of its reactors but due to the dual use nature of tritium and the Indian nuclear bomb program, less information about this is publicly available than for Canada.