# The Nuclear Safeguards (Notification) Regulations 2004, Paragraph 5.3.1: Gaseous diffusion barriers


(a) Especially designed or prepared thin, porous filters, with a pore size of 100-1,000 Å (angstroms), a thickness of 5 mm (0.2 in) or less, and for tubular forms, a diameter of 25 mm (1 in) or less, made of metallic, polymer or ceramic materials resistant to corrosion by UF6 ...
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Source: https://www.legislation.gov.uk/uksi/2004/1255/schedule/part/II/paragraph/5n4 (the official version)
Page: https://openlegislation.uk/nuclear-safeguards-notification-regulations-2004/schedule/part-II/paragraph-5n4
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.