Radioactive substances within the meaning of the Atomic Energy Act are:

  • nuclear fuels, i.e.
    • plutonium 239 and plutonium 241,
    • uranium enriched with the isotopes 235 or 233,
    • any substance containing one or several of the substances mentioned in a) and b),
    • substances which can be used in a suitable plant to maintain a chain reaction which initiates its own repetition and which are determined in an ordinance having the force of law.
  • other radioactive substances which – without being nuclear fuel -,
    • spontaneously emit ionizing rays,
    • contain one or several of the substances mentioned in a) or are contaminated with such substances.

The Radiological Protection Ordinance further distinguishes:

  • enclosed radioactive substances: radioactive substances which areenclosed by a tight, firm, inactive shell or permanently embedded in solid inactive substances so that the release of radioactive substances is prevented in the case of usual normal stress; a dimension must at least amount to 0.2 cm;
  • open radioactive substances: all radioactive substances except for enclosed radioactive substances;
  • short-lived radionuclides: radioactive substances with a half-life of up to 100 days;
  • long-lived radionuclides: radioactive substances with a half-life of more than 100 days.