Approaches to Disposal of Nuclear Waste Michael I. Ojovan

2022
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Figure 4. 
Schematic of nuclear waste classification of Germany. 
The German nuclear waste classification system is based on the heat-generating ca-
pacity of the waste and comprises two categories [19]: 
I.
Negligible-heat-generating radioactive waste is radioactive waste with negligible 
heat generation, i.e., average heat output of less than about 200 W/m
3
of waste (cor-
responding to a 3-degree K increase in temperature at the wall of the disposal cham-
ber caused by the decay heat from the radionuclides contained in the waste pack-
ages); 
II.
Heat-generating radioactive waste is characterised by high activity concentrations 
and, therefore, by high decay heat output. This category includes reprocessing resi-
dues and spent nuclear fuel. 
Additionally, radioactive waste cleared for disposal can be defined, which corre-
sponds to VLLW, following the IAEA classification explained above. According to Ger-
many’s policy, only solid (or solidified) radioactive waste will be accepted for disposal in 
deep geological formations. Liquid and gaseous waste is excluded from acceptance to be 
disposed of. The controlled and safe disposal of radioactive waste requires its condition-
ing, which comprises several stages dependent on the nature of the raw nuclear waste (see 
Figure 1b). The raw waste may first be pre-treated and then be either treated or condi-
tioned, preparing packages suitable for storage and/or disposal. Proven methods and re-
liable (both mobile and stationary) installations do already exist for the pre-treatment and 
conditioning of radioactive waste. Mobile conditioning installations are the preferred 
choice for the treatment and packaging of operational waste from nuclear power plants 
(NPPs). Stationary installations that are capable of conditioning various types of raw 
waste are typically used at the major research centres. There are also a number of other 
stationary conditioning installations that are operated on-site by the larger-scale nuclear 
waste producers. In addition to German facilities, facilities in other European countries 
are also utilised for nuclear waste processing, e.g., incineration facilities where the nuclear 
waste from the operation of nuclear facilities is delivered to Sweden for treatment and 
conditioning and subsequently returned to Germany for storage and disposal. Both cen-
tral and decentralised storage facilities are available for the storage of radioactive waste 
with negligible heat generation from NPPs and the nuclear industry. 

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