ATOMIC ENERGY AND RADIOACTIVE SUBSTANCES Commencement and Citation 1 These Regulations may be cited as the Nuclear Installations (Prescribed Sites) Regulations 1983 and shall come into operation on the 1st September 1983. Interpretation 2 In these Regulations the following expressions have the meanings hereby assigned to them, that is to say— “ A2 values ” means the values in curies specified for single radionuclides, in paragraphs 403 to 405 of the IAEA Regulations; for mixed fission products, in paragraph 406 of those Regulations; and for a single radioactive decay chain in which the radionuclides are present in their naturally occurring proportions, in paragraph 407 of those Regulations: “ associated nuclear fuel ” means a quantity of nuclear fuel intended and ready for use or in use or which has been used in a nuclear reactor and which is held in, or on the same site as, that nuclear reactor which does not exceed the quantity of nuclear fuel specified in the nuclear site licence relating to that nuclear reactor or any consent or approval granted under that site licence; “ fissile material ” means plutonium 239, plutonium 241, uranium 233, uranium 235 (where the mass of the isotope uranium 235 exceeds 1% of the total mass of all the uranium isotopes present), or any material containing any of them: “ form ” in relation to any radionuclide means the state in which it is found on the site and in particular whether or not it is a sealed source; “ group ” in relation to radionuclides means any of the four groups into which radionuclides are classified in the Table set out in Schedule 1 to these Regulations; “ the IAEA Regulations ” means the Regulations for the Safe Transport of Radioactive Materials 1973 Revised Edition (As Amended) published by the International Atomic Energy Agency in 1979; “ small nuclear reactor ” means a thermal neutron nuclear reactor designed to operate at a thermal power output not exceeding 600KW; “ relevant group limit ” means in relation to a radionuclide the limit in curies set out in the Table in Schedule 1 to these Regulations as being appropriate to the group to which that radionuclide belongs and in the case of a radionuclide which is in the form of a sealed source means the figure in the third column of that Table and in any other case the figure set out in the fourth column of that Table; “ sealed source ” means a radionuclide which is either sealed in a container or bonded wholly within material (otherwise than solely for the purpose of storage, transport or disposal) and includes the immediate container or bonding, but does not include any nuclear fuel element. Prescribed Sites 3 There is hereby prescribed for the purposes of section 16(1) of the Act any site in respect of which a nuclear site licence is for the time being in force on which: 1 the quantity of radionuclides present at any time is such that their total activity does not exceed the limits of activity prescribed in regulation 4 of these Regulations; or 2 the only nuclear reactor is a small nuclear reactor and the quantity of radionuclides outside the reactor other than associated nuclear fuel present at any time is such that their total activity does not exceed one half of the limits of activity prescribed in regulation 4 of these Regulations; and 3 in either case the total mass of fissile materials (other than those comprised in associated nuclear fuel) present at any time does not exceed the limits prescribed by regulation 5 of these Regulations. Prescribed Limits of Activity 4 1 Subject to the provisions of paragraph (2) and (3) below the limit of activity prescribed by this regulation shall be: a in the case of a site on which there is only a single radionuclide or on which there are several radionuclides all of which are in the same group and in the same form, the relevant group limit; and b in any other case, such that the sum of the fractions produced by dividing the activity of each radionuclide by its relevant group limit does not exceed one. 2 Where the identity of a radionuclide is not known it shall be deemed to be included in group 1. 3 For the purposes of the calculation to be made in accordance with paragraph (1)(b) of this regulation, where the respective activities of any of the radionuclides present are not known all such radionuclides shall be deemed to belong to the most restrictive group among them. Additional limits for fissile material 5 For the purpose of regulation 3 of these Regulations total mass limits for fissile material shall be: a for a site on which there is only one of the materials specified in the first column of the Table set out in Schedule 2 to these Regulations, the mass set out in the second column of the said Table and b such that for a site on which there is more than one of the materials specified in column 1 of the Table set out in Schedule 2 to these Regulations, the sum of the fractions obtained by dividing the mass of each of the materials present on that site by the limit set out in the second column of the said Table in respect of that material shall not exceed one. Peter Walker Secretary of State for Energy Dated 24th June 1983 George Younger Secretary of State for Scotland Dated 28th June 1983