# The Nuclear Installations (Prescribed Sites) Regulations 1983, Schedule 2


Fissile Material
Limits in grammes of fissile nuclide
Plutonium 239
375
Plutonium 241
375
Uranium 233
375
Uranium 235 (when the mass of the uranium 235 exceeds 1% of the total mass of all the uranium isotopes present)
600

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Source: https://www.legislation.gov.uk/uksi/1983/919/schedule/2 (the official version)
Page: https://openlegislation.uk/nuclear-installations-prescribed-sites-regulations-1983/schedule-2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.