5Meaning of derived activity value and activity

5  Meaning of derived activity value and activity

 (1) The derived activity value for an inventory or waste package of NNP material is worked out as follows:

 (a) first, divide the activity of each nuclide in the NNP material by the activity value specified in clause 1 of Schedule 2 for the nuclide;

 (b) secondly, if there is more than one nuclide in the NNP material, total the result of paragraph (a) for each nuclide.

Note: Section 6 affects how the activity of a parent nuclide mentioned in clause 2 of Schedule 2 (or marked a in clause 1 of Schedule 2) is worked out, by providing for inclusion of the activity of certain progeny nuclides that are included in secular equilibrium with the parent nuclide.

 (2) The activity of a nuclide is the rate at which nuclear transformations of the nuclide occur, worked out in accordance with the definition of activity in the IAEA Nuclear Safety and Security Glossary, Terminology Used in Nuclear Safety, Nuclear Security, Radiation Protection and Emergency Preparedness and Response, 2022 (Interim) Edition, published by the International Atomic Energy Agency, as existing on 5 June 2025.

Note: The Glossary could in 2025 be viewed on the website of the International Atomic Energy Agency (https://www.iaea.org).