General

In Germany, radioactive waste is classified into waste with negligible heat generation and heat-generating waste.

For waste with negligible heat generation the heat release per waste package is in the milliwatt range. Consequently, the temperature increase in the surrounding rock, the host rock, caused by this heat release is minor. In the case of heat-generating waste, however, the heat release is in the kilowatt range which can cause a temperature increase in the adjoining host rock of more than one hundred degrees centigrade. To cool down the waste and to optimally use the available repository space and thus to minimise the costs of final disposal, heat generating waste is placed in surface interim storage facilities for several decades.

Radioactive waste with negligible heat generation includes, among others, filters and tools, chemical wastewater, sludges / suspensions, cleaning materials and contaminated metals and non-metals.
Heat-generating radioactive waste are primarily spent fuel assemblies intended for direct disposal and vitrified radioactive waste from the reprocessing of German spent fuel elements in France and the United Kingdom.

First, the radioactive waste is reduced in its volume as much as possible (compacted) and subsequently conditioned, i.e. processed into a shape and packaging that is suitable for final disposal.

Radioactive waste with negligible heat generation: Liquid radioactive materials are concentrated, e.g. by vaporizing the non-active liquid component; solid radioactive materials are crushed and compressed or, if possible, burned to ashes. Then, the waste is placed into drums, or containers made of steel or concrete that are suitable for final disposal.

Heat-generating waste: At present, fuel assemblies intended for direct disposal are not reduced in their volume. Instead, complete fuel assemblies are inserted into Castor casks and placed into interim storage. Stainless steel canisters containing vitrified waste from reprocessing are also placed into Castor casks for interim storage. For final disposal, the spent fuel elements will probably be transferred into suitable disposal containers, e.g. in so-called Pollux casks. These are similar to Castor casks but are not reused.

Every year, the Federal Office for Radiation Protection, (BfS), inventories the amount of untreated radioactive residues as well as the production and amount of conditioned radioactive waste.

Predictions of the expected waste production assume a cumulated waste package volume of approx. 290,000 m³ of radioactive waste with negligible heat generation until the year 2080 and approx. 24,000 m³ of heat-generating waste (Projection of BfS: Publication date 22.11.2005)