Commonwealth Numbered Regulations Commonwealth Numbered Regulations(1) For the purposes of this instrument, in determining the activity of a parent nuclide mentioned in an item of Part 2 of Schedule 1, include the activity of any progeny nuclide mentioned in that item that is included in secular equilibrium with the parent nuclide.
Note: Parent nuclides are also marked a in Part 1 of Schedule 1.
(2) Except for the purposes of determining under subsection (1) the activity of a parent nuclide mentioned in an item of Part 2 of Schedule 1 , the activity of a progeny nuclide mentioned in an item of that Part is taken to be nil when included in secular equilibrium with a parent nuclide mentioned in that item.