Every intrinsically radioactive material, such as any material contaminated by radioactivity, which have no further use foreseen is considered as radioactive waste. Therefore, the term radioactive waste encompasses a wide range of radioactive isotopes in a variety of physical and chemical forms.
This wastes are classified in four different types, depen- ding on their half–life (time taken for half of its atoms to decay, and thus for it to lose half of its radioactivity):
- Low-level waste: Materials with low radioactivity. It does not require shielding during handling and transport, and are suitable for disposal in near surface facilities- This waste comprises about the 90% of the volume but only 1% of the radioactivity of all radioactive waste.
- Intermediate-level waste: It is more radioactive than low-level waste, although not enough to take it into account in the design or selection of storage and disposal However, it does require some shielding. This type of waste entails about 7% of the volume and has 4% of the radioactivity of all radioactive waste.
- High-level waste: These wastes are sufficiently radioactive for their decay heat (>2kW/m3) to increase its team- temperature, and the temperature of their surroundings, Therefore, they require cooling and shielding. High-level wastes comprise just 3% of the volume of radioactive wastes, but 95% of the total radioactive- waste of produced by them.
- Very low-level waste: These wastes contain radioactive materials at a level that is not considered harmful to people or the surrounding environment, such as demolished material (concrete, plaster, bricks, metal, valves, piping, ) produced during rehabilitation or dismantling operations on nuclear industrial sites, or some wastes originated in industries such as food processing, chemical, steel, or steel.
Generally, they are disposed of with domestic refuse, although some countries are currently developing disposal facilities specifically designed for the storage of this type of waste.
Why is radioactive waste a hazardous substance?
Radioactive waste is considered as hazardous substances due to the damaging effects that improperly handled, transported and/or stored can cause both, the environ- ment and human health.
In regard to the environment, radiation coming from radioactive waste can contaminate ground and water for long time, up to several decades. This situation will pro- duce disastrous effects on animals and plants which live in or around the contaminated areas.
Besides, the radioactivity of this wastes can have really negative effects on the human body. A very high level of radiation exposure delivered over a short period of time can cause symptoms such as nausea and vomiting and in the most severe cases can even result in death over the following days or weeks.
For its part, exposure to low-levels of radiation does not cause immediate health effects, but can cause an increase in the risk of cancer over a lifetime. Children and foetu- ses are especially sensitive to radiation exposure, as their cells divide rapidly, providing more opportunity for radia- tion to disrupt the process and cause cell damage.
Where can radioactive waste be found?
Radioactive waste is produced in several industries and activities, which are exposed below
- Mining through to fuel fabrication: Traditional uranium mining generates fine sandy tailings, which contain virtually all the naturally occurring radioactive elements found in uranium ore.
- Electricity generation: Nuclear plants generate radioactive wastes, not only in the electricity generation process, but as a result of general ope- rations, such as the cleaning of reactor cooling sys- tems and fuel storage ponds, and the decontamina- tion of equipment, filters, and metal components that have become radioactive as a result of their use in or near the reactor.
- Reprocessing of used fuel.
- Decommissioning nuclear plants: In the case of nuclear reactors, about 99% of the radioactivity is associated with the fuel. Some scrap material from decommissioning may be recycled, but for uses outside the industry very low clearance levels are applied, so most is buried and some is recycled within the industry.
- Legacy waste: This waste exists in several coun- tries that pioneered nuclear power and especially where power programs were developed out of mili- tary programs.
- National laboratory and university research activities
- Industrial gauges and radiography sources
- Nuclear medicine activities at hospitals
Below, you can find some of the most relevant contents regarding radioactive waste:
- IAEA considerations
- Decommissioning of nuclear powerplants
- Decontamination of nuclear facilities in Sweden
- Decontamination and management of metals in decommissioning of nuclear installations
This article can be found in the 2021 edition of the document. Find the full publication here:
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