Geological disposal involves emplacing radioactive waste deep underground in a stable environment. Placing multiple barriers between the waste and the biosphere protects both people and the environment from the harmful effects of this waste.
When we talk about barriers, a distinction is made between the natural barrier, i.e. the stable geological formation in which the waste is located, and man-made (engineered) barriers, i.e. the various layers of packaging around the waste as well as backfill materials. The engineered barriers ensure that the radioactive waste is physically contained. If, after a long time, these engineered barriers became damaged and radioactive substances were to be released from the waste packages, the properties of the natural barrier would ensure that these substances dispersed very slowly. Isolationdeep underground means that the probability and consequences of human intrusion remain limited. It also ensures that any changes on the earth’s surface over the required long timescales have little or no impact on the safety of the disposal system. Physical containment, isolation and retarded dispersion are the system’s three safety functions.
You can find more information on the ONDRAF/NIRAS website.
Belgian research on geological disposal focuses on the Boom Clay and Ypresian Clay.
These clay formations may be a suitable host because they are practically impermeable to water and can retain radioactive substances for a very long time, preventing them from spreading quickly. These deep clay layers are also plastic, like modelling clay. Any fissures that form will reseal themselves. Moreover, the clay formations under investigation are already tens of millions of years old and are stable. Watch this film to find out more.