The planned Konrad repository

Germany has decided in favour of maintenance-free and safe radioactive waste disposal in deep, stable geological formations. Repositories in deep geological formations such as the Konrad repository are located several hundred metres below the earth's surface and are isolated from the biosphere over long periods of time.

Among other things, stable geological formations means that they are also earthquake-safe; isolated from the biosphere means that e.g. no radioactive substances can be discharged into the groundwater. The site of the Konrad repository has very favourable geological conditions to serve as a repository mine.

Isolation from the biosphere

Simplified West–East cross section in the region of the Konrad mine, Shaft 2

The iron-ore containing rock layers forming the so-called host rock are located in a depth between 800 and 1,300 metres. That is where the repository's emplacement fields will be built. Above the iron-ore containing rock layers there is an about 400-m thick clay layer which is impermeable to water. This means that the entrance area of the Konrad repository does not have a hydraulically effective connection to the groundwater near the surface. This natural barrier ensures that the radioactive waste will be isolated from the biosphere.

Short distances: Start of emplacement near shaft 2

Altogether eleven emplacement fields have been licensed for the Konrad repository but not all of them will be needed. Until emplacement operations start, only field 5.1 in a depth of about 800 metres will be driven and thus be usable as emplacement location. The 800-m level is as safe as the 1,300-m level. For operational reasons it is reasonable to start emplacement of the radioactive waste in field 5.1, given that the distance between shaft 2 and this emplacement field is short.

Limited emplacement volume of 303,000 cubic metres

In the partial field 5.1 there will be room for 63,000 cubic metres of radioactive waste with negligible heat generation. Remaining cavities will be backfilled with iron-ore concrete and subsequently be sealed. As circumstances require, emplacement chambers will be driven in the emplacement chambers, but only to the extent permitted by the plan-approval decision, namely maximum 303,000 cubic metres.