Editing Sellafield (section)

===Plutonium Recovery Plant criticality===
On 24 August 1970, a criticality incident occurred in the Plutonium Recovery Plant.<ref>{{Cite journal |last=Daniels |first=J |display-authors=etal |title=Criticality Incident – August 24, 1970 |url=https://ncsp.llnl.gov/LA13638/reports/025.ref_025.pdf |journal=International Developments in Criticality Safety |pages=35–36 |access-date=12 April 2020 |archive-date=12 April 2020 |archive-url=https://web.archive.org/web/20200412233507/https://ncsp.llnl.gov/LA13638/reports/025.ref_025.pdf |url-status=live }}</ref>

The plant recovered plutonium from miscellaneous sources and was considered tightly controlled. Plutonium was dissolved and transferred into a solvent extraction column through a transfer vessel and backflow trap. Unexpectedly, {{convert|2.15|kg|abbr=on}} of plutonium had accumulated in the transfer vessel and backflow trap and become just sub-critical. As an organic solvent was added to the aqueous solution in the vessel, the organic and aqueous phases separated out with the organic layer on top. This solvent extracted plutonium from the aqueous solution with sufficient concentration and geometry to create a criticality.<ref>{{Cite book |last=McLaughlin |title=A Review of Criticality Accidents |publisher=Los Alamos National Laboratory |year=2000 |pages=43–44 |display-authors=etal}}</ref>

Two plant workers were exposed to radiation.<ref>{{Cite book |url=https://inis.iaea.org/collection/NCLCollectionStore/_Public/27/060/27060437.pdf |title=Significant Incidents in Nuclear Fuel Cycle Facilities |publisher=IAEA |year=1996 |page=36 |access-date=12 April 2020 |archive-date=12 April 2020 |archive-url=https://web.archive.org/web/20200412233511/https://inis.iaea.org/collection/NCLCollectionStore/_Public/27/060/27060437.pdf |url-status=live }}</ref>