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Nuclear waste management

The practical uses of radioactivity — whether in nuclear medicine, research laboratories, military applications, and the electronuclear industry — generate waste that must be disposed of safely. This waste is characterized by its level of radioactive activity and its duration, which determine how dangerous it is. Four categories have been defined:
- The first two are long-lived high level waste (HLW-LL) and long-lived intermediate level waste (ILW-LL). This is mainly waste from the reactor core that remains strongly radioactive and will retain considerable radioactivity for hundreds of thousands or even millions of years. This waste does not, however, remain “highly radioactive” on a geological scale — it gradually transforms into long-lived low-level waste (LLW-LL). Permanent storage is currently the preferred option in France, where the Parliament will be reviewing all related decisions over the next few years.
- Short-lived low and intermediate level waste (LILW-SL). This is mostly technological equipment (gloves, overalls, tools, etc.) contaminated through use in a nuclear plant.
- Lastly, very low level waste (VLLW), consisting mostly of contaminated materials like scrap metal, rubble and concrete from the dismantlement of a nuclear site. Although it is not strongly radioactive, this waste is expected to generate greater volumes than those of the other categories.
The associated management system is already operational, in particular in the ANDRA1 repositories.
For financial and safety reasons, each storage solution must be adapted to the nature of the waste. Due to its level of radioactivity and lifespan, short-lived very low level and low and intermediate level waste does not require deep underground storage. Similarly, long-lived low-level waste can be stored at medium depths, between 15 and 200 meters underground. Deep underground storage, the option that has been chosen by several countries including France, is solely intended for long-lived high and intermediate level waste, which represents about 0.2% of the total volume of radioactive waste.
In France, ANDRA studies and validates this storage method at the Bure underground laboratory in the northeastern part of the country. If the trials are conclusive and the government gives its approval, a deep storage repository will be built nearby, i.e. in a geological layer similar to the one where the studies have been carried out. Nuclear repositories are built in non-seismic areas, in geological formations with very little groundwater (e.g. argillaceous rock or granite).
The concept of deep underground storage is presented as a solution that does not burden future generations with the management of the waste produced today. In the longer term, its supporters argue that underground storage is also a response to a potential breakdown of society in the future. The storage sites are designed to be safe even if they fall into oblivion and are no longer monitored — it is a passive concept where safety does not depend on future generations.
Opponents, on the other hand, believe that burying radioactive waste is not a viable solution, as illustrated by the example of Germany's Asse site in Lower Saxony. This nuclear repository in a former salt mine was infiltrated by water, resulting in the contamination of the surrounding area. Critics also emphasize that a society capable of operating nuclear reactors and managing the associated risks should be able to propose a more reversible waste management solution, with the possibility of benefiting from future technological breakthroughs. They point out that, in any case, the most highly radioactive waste can only be buried after about 70 years of storage above ground, the time needed for its power of decay to subside to a point that it will not cause excessively high temperatures underground.