Internationally, several different systems have been developed for the clas­sification of radioactive wastes. These are generally based on half-life, activ­ity levels, origin or source, or the degree of isolation required. In general, low level waste (LLW) contains radionuclides with low activities and short half-lives and generates no heat; some systems differentiate a subcategory for very low level waste (VLLW). Intermediate level waste (ILW) may contain radionuclides with low to intermediate activities and short to long half-lives, generating no to negligible heat. High-level waste (HLW) con­tains radionuclides with high activities, long or short half-lives or both, and generates heat (Rempe, 2007).

In Germany, as mentioned earlier, the BMU defines nuclear waste for disposal purposes based on its heat generating capacity, as either waste with negligible heat generation or heat-generating waste. In the German system waste with negligible heat generation consists of VLLW, LLW and ILW, while waste classified as heat generating consists of both spent nuclear fuel (SNF) and HLW. In accordance with federal policy as promulgated by the BfS, both waste types are to be disposed of in waste-specific deep geological repositories (BfS, 2011c). Construction, operation and closure of a reposi­tory must be approved according to the Atomic Energy Act (AtG §9b) as part of a planning approval process.

The major sources of radioactive wastes in Germany are associated with nuclear fuel cycle activities, power generation, research facilities, the re­importation of HLW associated with the reprocessing of SNF in the United Kingdom and France, decommissioning of the various nuclear facilities, and the use of radioisotopes in medical, research and industrial applications. Other materials, primarily associated with the decommissioning of nuclear facilities, which are either not radioactive or only weakly radioactive, can be released from nuclear regulatory control by permit providing applicable regulatory conditions are met (Chapter 2, Section 9, §29 of StrlSchV). The BfS estimates that a total of approximately 290,000 m3 of waste with negli­gible heat-generating capacity will require disposal (BfS, 2011d). Of these, approximately 161,000 m3 of the waste is expected from decommissioned NPPs by 2080 (BfS, 2011c). The current inventory of heat-generating nuclear waste requiring geological disposal in Germany as of 31 December 2010 is given in Table 14.1.