Editing Manhattan Project (section)

=== Canadian sites ===
{{Main|Montreal Laboratory}}

Canada provided research, extraction and production of uranium and plutonium, and Canadian scientists worked at Los Alamos.<ref>{{Cite web |last=Commission |first=Canadian Nuclear Safety |title=Canada's historical role in developing nuclear weapons |url=https://www.cnsc-ccsn.gc.ca/eng/resources/fact-sheets/canadas-contribution-to-nuclear-weapons-development/ |access-date=2024-05-23 |website=www.cnsc-ccsn.gc.ca}}</ref><ref>{{cite news|first=Tyler |last=Dawson |title=Canada's contributions to the atomic bomb developed by Oppenheimer |newspaper=National Post |date=24 July 2023 |url=https://nationalpost.com/news/canada/canadas-atomic-bomb-oppenheimer |access-date=25 May 2024}}</ref>

==== British Columbia ====
[[Cominco]] had produced electrolytic hydrogen at [[Trail, British Columbia]], since 1930. Urey suggested in 1941 that it could produce heavy water. To the existing $10&nbsp;million plant consisting of 3,215 cells consuming 75&nbsp;MW of hydroelectric power, secondary electrolysis cells were added to increase the deuterium concentration in the water from 2.3% to 99.8%. For this process, [[Hugh Stott Taylor|Hugh Taylor]] of Princeton developed a platinum-on-carbon [[catalyst]] for the first three stages while Urey developed a nickel-[[chromium(III) oxide|chromia]] one for the fourth stage tower. The final cost was $2.8&nbsp;million. The Canadian Government did not officially learn of the project until August 1942. Trail's heavy water production started in January 1944 and continued until 1956. Heavy water from Trail was used for [[Chicago Pile 3]], the first reactor using heavy water and natural uranium, which went critical on 15 May 1944.<ref name="Waltham, pp. 8-9">{{harvnb|Waltham|2002|pp=8–9}}.</ref>

==== Ontario ====
The [[Chalk River Laboratories|Chalk River, Ontario]], site was established to rehouse the Allied effort at the [[Montreal Laboratory]] away from an urban area. A new community was built at [[Deep River, Ontario]], to provide residences and facilities for the team members. The site was chosen for its proximity to the industrial manufacturing area of Ontario and Quebec, and proximity to a rail head adjacent to a large military base, [[Camp Petawawa]]. Located on the Ottawa River, it had access to abundant water. The first director of the new laboratory was [[Hans von Halban]]. He was replaced by John Cockcroft in May 1944, who was succeeded by [[Bennett Lewis]] in September 1946. A pilot reactor known as [[ZEEP]] (zero-energy experimental pile) became the first Canadian reactor, and the first to be completed outside the United States, when it went critical in September 1945; ZEEP remained in use by researchers until 1970.<ref>{{cite web |url=http://www.sciencetech.technomuses.ca/english/whatson/zeep.cfm |archive-url=https://web.archive.org/web/20140306233719/http://www.sciencetech.technomuses.ca/english/whatson/zeep.cfm |archive-date=6 March 2014 |title=ZEEP – Canada's First Nuclear Reactor |publisher=Canada Science and Technology Museum}}</ref> A larger 10&nbsp;MW [[NRX]] reactor, which was designed during the war, was completed and went critical in July 1947.<ref name="Waltham, pp. 8-9" />

==== Northwest Territories ====
The [[Eldorado Mine (Northwest Territories)|Eldorado Mine]] at [[Port Radium]] was a source of uranium ore.<ref>{{harvnb|Jones|1985|pp=8, 62}}.</ref>