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Waste types

At the international level there are numerous options to classify radioactive waste. Classification of the waste depends on the planned way of disposal (deep geological formations or near the surface) or the necessary handling of the waste.

On account of the dose rate one frequently differentiates between high-level radioactive waste (HAW), intermediate-level radioactive waste (MAW) and low-level radioactive waste (LAW). At the international level experts agree that high-level radioactive waste must be stored in deep geological formations in order to isolate the waste safely from man and environment. However, in some states low-level and intermediate-level radioactive waste is stored near the surface and, as opposed to the high-level radioactive waste, not in deep geological formations.

As one intends to dispose of all types of radioactive waste in deep geological formations in Germany and as therefore not the dose rate is the essential quantity but the radioactive inventory and the heat generated during the radioactive decay, the radioactive waste is divided into heat-generating waste and waste with negligible heat generation.

Radioactive waste with negligible heat generation

The term "radioactive waste with negligible heat generation" was quantified in the scope of the planning works for the Konrad repository. The basis of these works was that the temperature conditions prevailing underground were only to be affected slightly by the emplaced waste packages. The implementation of this planning requirement led to the establishment that the increase in the host rock’s temperature caused by the decay heat of the radionuclides contained in the waste packages must not exceed 3 degrees (Kelvin) on average. This value corresponds to the natural temperature difference at a depth difference of 100 metres in mines. Compared to the temperature change caused by ventilation, it is small. Due to the cooler air supplied through ventilation the host rock is already exposed to clearly larger temperature fluctuations. The temperature difference of 3 Kelvin corresponds to a mean thermal output of about 200 watt per cubic metre of waste.

Waste with negligible heat generation encompasses, among others, disused plant components and components such as pumps and pipelines, ion-exchange resins and air filters from waste water and exhaust air treatment, contaminated tools, protective clothing, decontamination and cleaning agents, laboratory waste, sealed radiation sources, sludges, suspensions or oils.

Waste with negligible heat generation corresponds to the established categories of low-level and to the major part of intermediate-level radioactive waste (LAW and MAW).

Heat-generating waste

Heat-generating radioactive waste is characterised by high activity concentrations and thus high decay heat. Among this waste are in particular the fission product concentrate, the hulls and ends and the feed clearing sludge (residues from the dissolution of spent fuel elements) as well as the spent fuel elements themselves provided that they have not been reprocessed but are to be disposed of directly as radioactive waste.

Heat-generating waste correspond to high-level radioactive waste (HAW) and a part of the intermediate-level radioactive waste (MAW).

Spent fuel elements

The major part of the spent fuel elements is currently not yet declared as waste. Spent fuel elements originate from the operation of commercial nuclear power plants (power reactors) and research reactors.

Part of the spent fuel elements from Germany were reprocessed in France and the UK – i.e. uranium and plutonium were separated from the fuel elements in a large-scale process and partially processed in new fuel elements. Waste being produced in this process was partially already returned to Germany or will be returned to Germany, respectively.

Spent fuel elements that have not been reprocessed are stored in interim storage facilities in Germany until they will be directly disposed of.

State of 2016.08.15

© Federal Office for the Safety of Nuclear Waste Management