Radioactive waste is the residual "useless" products generated from human activities entailing radioactive materials. Radioactive materials are commonly used in:
- medicine, for diagnostic examinations and nuclear medicine treatments (i.e. use of radiopharmaceutical products), as well as for radiotherapies (e.g., irradiation of tumors, intra-tissue implants);
- industry, for radiography purposes, sterilization purposes, quality control (e.g., measurement of thickness of materials), etc.;
- research and training, e.g. biological experiments, chemistry experiments;
- other specialized applications.
The decay time
Just like all radioactive materials, radioactive waste decays based on the half-life of the isotope included therein. For example, an amount of cobalt (Co-60) will remain half after a period of 5.6 years, which is the half-life of cobalt (Co-60). Each isotope has its own half-life, which may be extremely short, e.g. just 12 seconds for barium (Ba-143) or even extremely long, e.g. 1577 years for radium (Ra-226), 5730 years for carbon (C-14) and 4.5 billion years for uranium (U-238). Thus, some isotopes, and consequently radioactive waste, never "die" and a long-term and careful treatment in special installations is required, whilst a simple in-situ management is enough for short-lived isotopes.
Due to the hazard to public health and environment, radioactive waste has to be managed either directly by their producer or in the long-term within specialized facilities. According to the international standards, the following two methods of radioactive waste management may be applied:
• by release to the environment, provided that the established clearance levels are met. Such clearance levels have been set, on the condition that no person should receive a radiation dose above 10 μSv (microsievert) per year due to the total releases of radioactive substances into the environment. It should be noted that the dose limit for a person from all practices with ionizing radiation is 1000 μSν per year.
• by disposal (emplacement without intention of retrieval) within a radioactive waste disposal facility. There are several types of installations for the disposal of radioactive waste, such as land field disposal, near surface disposal, borehole, etc. The selection of the type of the disposal facility depends on multiple factors, such as the kind, the form, the status and the quantity of radioactive waste, the packaging of radioactive waste, the existing and future environmental, geological, seismic and climate conditions, the conducted studies (e.g. environmental, geological, hydrological, seismic) and the related scientific, research and development programs carried out, the programs for area reformations, the existing and future infrastructure, financial and social factors, etc.
What is the difference with nuclear waste
Nuclear waste refers to the nuclear spent fuel (containing uranium and fission products), which no longer may be used for the operation of a reactor. Due to their characteristics, their hazard and the need for special treatment, spent fuel, although being radioactive waste, is referred to and handled separately. Deep geological disposal is the generally accepted method for nuclear waste management.
The national responsibility
Pursuant to Directive 2011/70/Euratom, each Member-State is responsible and undertakes the management of the radioactive waste generated within its territory.
The permanent and indefinite storage of the radioactive waste is not considered to be a final waste management solution (it is not a technically sustainable solution and is not in compliance with the European legal framework), whilst there are no means for the destruction of radioactive waste (e.g. incineration).
According to the national policy for the management of radioactive waste, the import of waste to Greece is strictly and explicitly prohibited.