About radioactive waste

Radioactive waste by its nature generally does not differ much from other types of industrial waste. Examples of this type of waste may be devices, dismantled appliances, overalls, filters and impure liquids contaminated with radionuclides or containing them, which are no longer foreseen to be used in future. Radioactive waste, however, is characterized by the fact that it emits ionizing radiation which poses danger to humans and the environment. Ionizing radiation continues until radionuclides within them decay.

While undergoing decay, a nucleus may emit alpha or beta particles and gamma radiation:

Alpha particle; Gamma radiation; Beta particle
Figure 1: Types of radiation when a nucleus decays.

Not all types of waste are equally dangerous. The level of danger posed by radioactive waste is determined by the intensity of ionizing radiation being emitted. That intensity depends on the type and amount of radionuclides contained in the waste. While radiation of some radionuclides cannot penetrate through very simple protective barriers, radiation of other radionuclides require concrete or lead barriers to prevent it from penetrating through.

Alpha particle; Beta particle; Gamma radiation; Paper, Aluminium; Concrete, lead or steel
Figure 2: Protective barriers. A sheet of paper is sufficient for stopping alpha particles. Beta particles are stopped using a 1 cm thick aluminium layer. The most penetrative is gamma radiation.

Waste is classified according to the level of danger posed by it. Classification not only facilitates the selection of methods and measures appropriate for waste management, but also the method of final disposal of waste. Although there is no unanimous waste classification system (classification in various countries slightly differs), the following categories of waste are often distinguished:

  • No longer controlled (“clean”) waste. It contains radionuclides the activity of which is insignificant and it does not pose danger to humans and the environment. The waste of this type is usually managed and disposed of or reused in the same way as other non-radioactive waste;
  • Short-lived radioactive waste of very low activity;
  • Short-lived low-level radioactive waste;
  • Short-lived intermediate-level radioactive waste;
  • Long-lived very-high-level radioactive waste.