Editing CANDU reactor (section)

==Nuclear nonproliferation==
{{main|Nuclear proliferation}}
In terms of safeguards against nuclear weapons [[nuclear proliferation|proliferation]], CANDUs meet a similar level of international certification as other reactors.<ref>{{cite web |url=https://inis.iaea.org/search/search.aspx?orig_q=RN:35034554 |title=Safeguards spent-fuel bundle counter for CANDU 6 reactors |publisher=IAEA – INIS |date= 2001 |access-date=17 April 2018|last1=Aydogdu |first1=K. M. }}</ref> The plutonium for India's first nuclear detonation, [[Operation Smiling Buddha]] in 1974, was produced in a [[CIRUS reactor]] supplied by Canada and partially paid for by the Canadian government using heavy water supplied by the United States.<ref>[http://www.ccnr.org/exports_3.html#3.2.2 Exporting Disaster ~ The Cost of Selling CANDU Reactors (3)]. Ccnr.org. Retrieved on 29 March 2018.</ref> In addition to its two PHWR reactors, India has some safeguarded [[pressurised heavy-water reactor]]s (PHWRs) based on the CANDU design, and two safeguarded light-water reactors supplied by the US. Plutonium has been extracted from the spent fuel from all of these reactors;<ref>{{cite journal| url = http://www.wisconsinproject.org/pubs/articles/1987/stoppingindianbomb.htm| first = Gary| last = Milhollin| journal = The American Journal of International Law| date = July 1987| title = Stopping the Indian Bomb| doi = 10.2307/2202014| volume = 81| issue = 3| pages = 593–609| jstor = 2202014| publisher = American Society of International Law| s2cid = 143062963| access-date = 1 June 2006| archive-url = https://web.archive.org/web/20060908192358/http://www.wisconsinproject.org/pubs/articles/1987/stoppingindianbomb.htm| archive-date = 8 September 2006| url-status = dead| url-access = subscription}}</ref> India mainly relies on an Indian designed and built military reactor called [[Dhruva reactor|Dhruva]]. The design is believed to be derived from the CIRUS reactor, with the Dhruva being scaled-up for more efficient plutonium production. It is this reactor which is thought to have produced the plutonium for India's more recent (1998) [[Operation Shakti]] nuclear tests.<ref>{{cite journal| first = David| last = Albright|date=September 1992| title = India's Silent Bomb| journal = Bulletin of the Atomic Scientists| volume = 48| issue = 7| pages = 27–31| url = https://books.google.com/books?id=pAwAAAAAMBAJ&pg=PA27| bibcode = 1992BuAtS..48g..27A| doi = 10.1080/00963402.1992.11460099| url-access = subscription}}</ref>

Although heavy water is relatively immune to neutron capture, a small amount of the deuterium turns into [[tritium]] in this way. This tritium is extracted from some CANDU plants in Canada, mainly to improve safety in case of heavy-water leakage. The gas is stockpiled and used in a variety of commercial products, notably [[Tritium illumination|"powerless" lighting systems]] and medical devices. In 1985 what was then Ontario Hydro sparked controversy in Ontario due to its plans to sell tritium to the United States. The plan, by law, involved sales to non-military applications only, but some speculated that the exports could have freed American tritium for the United States nuclear weapons program. Future demands appear to outstrip production, in particular the demands of future generations of experimental [[fusion reactor]]s like [[ITER]], with up to 10kg of tritium being required in order to start up a fusion reactor and so dozens of kilograms being required for a fleet. Between {{convert|1.5|to|2.1|kg}} of tritium were recovered annually at the Darlington separation facility by 2003, of which a minor fraction was sold.<ref>{{cite conference |conference=Fusion Development Paths Workshop |first=Scott |last=Willms |url=http://fire.pppl.gov/fesac_dp_ts_willms.pdf |archive-url=https://web.archive.org/web/20041017052832/http://fire.pppl.gov/fesac_dp_ts_willms.pdf |archive-date=2004-10-17 |url-status=live |title=Tritium Supply Considerations |publisher=Los Alamos National Laboratory |date=14 January 2003}}</ref>{{rp|10}} Consequently, the [[Canadian Nuclear Laboratories Research Facilities|Canadian Nuclear Laboratories]] in 2024 announced a decades-long program to refurbish existing CANDU plants and equip them with tritium breeding facilities.<ref>{{Cite web |title=UK and Canada team up to solve nuclear fusion fuel shortage |url=https://sciencebusiness.net/news/uk-and-canada-team-solve-nuclear-fusion-fuel-shortage |access-date=2024-03-10 |website=Science{{!}}Business |language=en}}</ref>

The 1998 Operation Shakti test series in India included one bomb of about {{convert|45|ktonTNT}} yield that India has publicly claimed was a hydrogen bomb. An offhand comment in the [[Bhabha Atomic Research Centre|BARC]] publication ''Heavy Water&nbsp;– Properties, Production and Analysis'' appears to suggest that the tritium was extracted from the heavy water in the CANDU and PHWR reactors in commercial operation. ''Janes Intelligence Review'' quotes the Chairman of the Indian Atomic Energy Commission as admitting to the tritium extraction plant, but refusing to comment on its use.<ref>{{cite web | url = http://www.ccnr.org/india_tritium.html | author =  Canadian Coalition for Nuclear Responsibility | title = Tritium from Power Plants gives India an H-bomb capability | date = 27 March 1996}}</ref> India is also capable of creating tritium more efficiently by irradiation of lithium-6 in reactors.