One of the main problems in the use of nuclear energy is the management of nuclear waste as it is very dangerous and difficult to eliminate.
What is done with nuclear waste?
Nuclear waste is one of the main problems related to nuclear energy. If these wastes are not treated properly, they are highly hazardous to the population and the environment.
Radioactive waste can be classified according to its physical and chemical characteristics and by its activity.
Classifying them by their activity we have:
- High-level nuclear waste, composed of elements of the fuel that has been made.
- Low-level nuclear waste is basically the tools, clothes and miscellaneous material used for the maintenance of a nuclear power plant.
The National Radioactive Waste Enterprise (ENRESA) is the company that is responsible for the management of nuclear waste in Spain (from nuclear power plants or other radioactive facilities such as hospitals and research centers related to nuclear energy). The management of such nuclear waste is defined in the General Waste Plan approved by Parliament.
The protocols for the treatment of nuclear waste depends on its level of radioactive activity:
Medium and low-level nuclear waste
Medium-sized nuclear waste is generated by radionuclides released in the fission process (which is currently used in nuclear power plants) in small quantities, much lower than those considered to be dangerous for the safety and security of persons.
With a treatment the radioactive elements contained in these by-products are separated and the resulting residues are deposited in steel drums solidifying them with tar, resins or cement.
Nuclear waste of low radioactive activity (clothes, tools, etc.) is pressed and mixed with concrete forming a solid block. As in the previous case these are also introduced into steel drums.
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In Spain, the drums are transferred to the Storage Center of El Cabril (Córdoba), which ENRESA is responsible for managing. In addition to depositing all nuclear waste from all Spanish nuclear plants, nuclear waste generated by medicine, research, industry and other fields that also work with nuclear energy is also deposited.
All nuclear waste stockpiles, currently, are closely monitored and controlled.
High activity nuclear waste
Once the fuel has been spent in a nuclear power plant, it is withdrawn from the reactor to be temporarily stored in a pool of water built of concrete and stainless steel walls inside the plant to create a radiation barrier and prevent leakage.
While it is true that these pools can be expanded by an operation called "reracking," the latest General Waste Plans envisage the construction of temporary dry storage facilities within the nuclear power plant itself. This would be a complement to the pools in the intermediate step until defining a definitive location.
The definitive storage research is being carried out in many countries, some of which, like Finland and the USA, have taken very important steps for their construction and commissioning.
One of the most accepted solutions among experts is Deep Geological Storage (AGP), usually in mines excavated in stable geological formations.
ENRESA is currently working to locate, construct and manage a Centralized Temporary Warehouse to temporarily and safely store the high-level nuclear waste currently stored in Spanish nuclear power plants. This storage will save time to find a suitable location for the AGP allowing the continuity of nuclear facilities and the safe storage of high-level waste.
European classification of nuclear waste
Since not all countries use the same classification, the European Commission has recommended the unification of criteria, proposing the following classification, effective as of January 1, 2002:
Transitional nuclear waste: wastes, mainly of medical origin, which disintegrate during the period of temporary storage and can then be managed as non-radioactive waste, provided that the de-classification values are respected.
- Low and medium activity nuclear waste: its concentration in radionuclides is such that the generation of thermal energy during its evacuation is sufficiently low. In turn, they are classified as short lived residues - containing nuclides with a half-life of less than or equal to 30 years, with a limited concentration of long-lived alpha radionuclides - and long-lived residues - with radionuclides and alpha-emitters Of long life whose concentration is higher than the limits applicable to short-lived waste.
- High-level nuclear waste: Residues with a concentration of radionuclides such that thermal generation during storage and disposal must be taken into account. This type of waste is mainly obtained from the treatment and conditioning of spent fuel.
Last review: May 1, 2015