# The Extradition (Protection of Nuclear Material) Order 1991, Chapter ANNEX II: TABLE: CATEGORIZATION OF NUCLEAR MATERIAL


Category
Material
Form
I
II
III(c)
(a) All plutonium except that with isotopic concentration exceeding 80% in plutonium–238.
(b) Material not irradiated in a reactor or material irradiated in a reactor but with a radiation level equal to or less than 100 rads/hour at one metre unshielded.
(c) Quantities not falling in Category III and natural uranium should be protected in accordance with prudent management practice.
(d) Although this level of protection is recommended, it would be open to States, upon evaluation of the specific circumstances, to assign a different category of physical protection.
(e) Other fuel which by virtue of its original fissile material content is classified as Category I and II before irradiation may be reduced one category level while the radiation level from the fuel exceeds 100 rads/hour at one metre unshielded.
1 Plutonium
Unirradiated
2 kg or more
Less than 2 kg but more than 500 g
500 g or less but more than 15 g
2 Uranium–235
Unirradiated – uranium enriched to 20% 235U or more
5 kg or more
Less than 5 kg but more than 1 kg
1 kg or less but more than 15 g
– uranium enriched to 10% 235U but less than 20%
10 kg or more
Less than 10 kg but more than 1 kg
– uranium enriched above natural, but less than 10% 235
10 kg or more
3 Uranium–233
Unirradiated
2 kg or more
Less than 2 kg but more than 500 g
500 g or less but more than 15 g
4 Irradiated fuel
Depleted or natural uranium, thorium or lowenriched fuel (less than 10% fissile content)

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Source: https://www.legislation.gov.uk/uksi/1991/1720/schedule/1/chapter/2 (the official version)
Page: https://openlegislation.uk/extradition-protection-of-nuclear-material-order-1991/schedule-1/chapter-2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.