A major environmental concern related to nuclear power is the creation of radioactive wastes such as uranium mill tailings, spent (used) reactor fuel, and other radioactive wastes.
These materials can remain radioactive and dangerous to human health for thousands of years.
Radioactive wastes are classified as low- level waste or high-level waste and pose hazardous properties for human health and the environment.
More information on these topics and other related ones, such as exposure limits can be found in the EDI Special Publication 2021.
By volume, most of the waste related to the nuclear power industry has a relatively low level of radioactivity.
Uranium mill tailings contain the radioactive element radium, which decays to produce the radioactive gas radon. Most uranium mill tailings are placed near the processing facility, or mill, where they come from.
Uranium mill tailings are covered with a sealing barrier of material such as clay to prevent radon from escaping into the atmosphere.
The sealing barrier is covered by a layer of soil, rocks, or other materials to prevent erosion of the sealing barrier.
The other types of low-level radioactive waste are tools, protective clothing, wiping cloths, and other disposable items that become contaminated with small amounts of radioactive dust or particles at nuclear fuel processing facilities and nuclear power plants.
Moreover, in the group of these low-level radioactive wastes, can be included the soil or parts of the plants to be removed in maintenance or decommissioning. This must be taken into account for the demolition.
The high-level radioactive waste consists of irradiated or spent, nuclear reactor fuel (fuel that is no longer useful for producing electricity). The spent reactor fuel is in a solid form, consisting of small fuel pellets in long metal tubes called rods.
In the UE, radioactive wastes are subject to special regulations that govern their handling, transportation, storage, and disposal to protect human health and the environment.
Decommissioning of nuclear plants
When a nuclear reactor stops operating, it must be decommissioned. The decommissioning of a nuclear installation, such as a power plant or research reactor, is the final step in its lifecycle.
Decommissioning involves safely removing from service the reactor and all equipment that has become radioactive and reducing radioactivity to a level that permits other uses of the property. And it encompasses activities from the shutdown and removal of nuclear material to the environmental restoration of the site.
EU countries have the ultimate responsibility for the nuclear safety of nuclear installations, including decommissioning operations, as outlined in the Euratom Directives on nuclear safety and management of spent fuel and radioactive waste. The directives mandate the highest safety standards for the operation of nuclear installations and for the management of the spent fuel and the radioactive waste they generated.
However, the whole process typically takes 20 to 30 years to complete and generally includes the following steps:
- Empty the fuel channels of the reactor (there are around 300 fuel channels in each reactor). A fuelling machine removes the fuel assembly from a channel and each fuel element is transferred to a cooling pond where it stays for a minimum of 90 days.
- Once cooled, the fuel is removed from the pond, packaged, and loaded into a container called a flask. The flask is transported to its final destination where it is further cooled and stored until it is safe to be disposed of.
- Once the site is without fuel the next stage of decommissioning can be carried out. The focus turns to the treatment and removal of low-level radiological and non-radiological wastes, along with the demolition and removal of redundant facilities.
- Some new construction may be required for radioactive waste management
processing. A facility for a safe storage option may also be built which will allow the reactor building to be left for a safe passive period, leaving the remaining radioactive materials to decay within the reactor core. After this long-term storage period, further demolition and final site clearance will be undertaken.
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This article can be found in the 2023 edition of the document. Find the full publication here:
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