Note: For class 7, the type of packaging may have a decisive effect on classification.

7.1 Definitions

  1. Radioactive material means any material containing radionuclides where both the activity concentration and the total activity in the consignment exceed the values specified in 2.7.2.2.1 to 2.7.2.2.6 in IMDG Code.

  2. Contamination

    Contamination means the presence of a radioactive substance on a surface in quantities in excess of 0.4 Bq/cm2 for beta and gamma emitters and low-toxicity alpha emitters, or 0.04 Bq/cm2 for all other alpha emitters.

    Non-fixed contamination means contamination that can be removed from a surface during routine conditions of transport.

    Fixed contamination means contamination other than non-fixed contamination.

  3. Definitions of specific terms

    A1 and A2

    A1 means the activity value of special form radioactive material which is listed in the table in 2.7.2.2.1 or derived in 2.7.2.2.2 in IMDG Code and is used to determine the activity limits for the provisions of IMDG Code.

    A2 means the activity value of radioactive material, other than special form radioactive material, which is listed in the table in 2.7.2.2.1 or derived in 2.7.2.2.2 in IMDG Code and is used to determine the activity limits for the provisions of IMDG Code.

    Fissile nuclides means uranium-233, uranium-235, plutonium-239, plutonium-241. Fissile material means a material containing any of the fissile nuclides. Excluded from the definition of fissile material are the following:

    1. Natural uranium or depleted uranium which is unirradiated;
    2. Natural uranium or depleted uranium which has been irradiated in thermal reactors only;
    3. Material with fissile nuclides less than a total of 0.25 g;
    4. Any combination of .1, .2 and/or .3.

    Low dispersible radioactive material means either a solid radioactive material or a solid radioactive material in a sealed capsule, that has limited dispersibility and is not in powder form.

    Low specific activity (LSA) material means radioactive material which by its nature has a limited specific activity, or radioactive material for which limits of estimated average specific activity apply. External shielding materials surrounding the LSA material shall not be considered in determining the estimated average specific activity.

    Low toxicity alpha emitters are: natural uranium; depleted uranium; natural thorium; uranium-235 or uranium-238; thorium-232; thorium-228 and thorium-230 when contained in ores or physical and chemical concentrates; or alpha emitters with a half-life of less than 10 days.

    Specific activity of a radionuclide means the activity per unit mass of that nuclide. The specific activity of a material shall mean the activity per unit mass of the material in which the radionuclides are essentially uniformly distributed.

    Special form radioactive material means either:

    1. An indispersible solid radioactive material; or
    2. A sealed capsule containing radioactive material.

    Surface contaminated object (SCO) means a solid object which is not itself radioactive but which has radioactive material distributed on its surface.

    Unirradiated thorium means thorium containing not more than 10-7 g of uranium-233 per gram of thorium-232.

    Unirradiated uranium means uranium containing not more than 2 x 103 Bq of plutonium per gram of uranium-235, not more than 9 x 106 Bq of fission products per gram of uranium-235 and not more than 5 x 10-3 g of uranium-236 per gram of uranium-235.

    Uranium – natural, depleted, enriched means the following:

    Natural uranium means uranium (which may be chemically separated) containing the naturally occurring distribution of uranium isotopes (approximately 99.28% uranium-238, and 0.72% uranium-235 by mass).

    Depleted uranium means uranium containing a lesser mass percentage of uranium-235 than in natural uranium.

    Enriched uranium means uranium containing a greater mass percentage of uranium-235 than 0.72%.

    In all cases, a very small mass percentage of uranium-234 is present.