|
|
|
Nuclear Safety > Decommissioning > Residue and Waste Management
|
|
Decommissioning: Residue and Waste Management
|
|
Both radioactive residues and deinstalled or dismantled radioactive plant components are the result of decommissioning a nuclear facility. According to § 9a of the Atomic Energy Act these must either be recycled safely (e.g. cleared or reused in another facility licensed under atomic or radiation protection legislation), or disposed of correctly as radioactive waste.
Various disposal routes exist for residues and waste materials.
ReleaseRelease is regulated by § 29 of the Radiation Protection Ordinance, as well as appendices III and IV.
|
|
Measuring facility used to release batches of residual material from the decommissioning of the Greifswald nuclear power plant (KGR). Source: EWN GmbH (For a larger view, please click on the picture)
|
Unrestricted releaseIn the case of unrestricted release, the relevant authority conducts the necessary administrative steps to release any residue from supervision as stipulated by the atomic legislation; these may then be reused, recycled or disposed of in the same way as standard waste. Materials are only awarded unrestricted release if measurements show that they do not exceed the release threshold for unrestricted release as laid down in the Radiation Protection Ordinance. This means their release must not cause individual members of the population to be exposed to an effective annual radiation dose of more than ten microsievert.
Specified releaseA second option is that of specified release. This is applied to residues suitable for disposal in a conventional waste disposal or incineration facility, subject to their adherence with the relevant release thresholds specified in § 29 of the Radiation Protection Ordinance. Specified release includes the release of solid materials for disposal, liquid substances for disposal, buildings for demolition, and scrap metal for recycling in a conventional melting plant.
Moreover, contaminated scrap metal may also be melted down in a controlled way if the release thresholds of the Radiation Protection Ordinance for specified release are exceeded.
Disposal as radioactive wasteMaterials which can neither be recycled nor cleared for release must be disposed of as radioactive waste. An estimated 5,000 m3 of conditioned decommissioning waste is created by the decommissioning of a single nuclear power plant. Decommissioning waste is waste with negligible heat generation. The waste must be stored at an interim storage facility until the Konrad repository for low and medium radioactive waste becomes available. This generally takes place in an interim storage facility on the site of the plant.
Prior to transporting the radioactive waste to an interim storage facility or final repository, it must be treated appropriately (conditioned). Solid waste, for instance, undergoes compacting. Liquid waste is given a solid form, e.g. by means of drying/evaporation or cementation. When transporting conditioned waste to an interim storage facility, current traffic regulations must be observed. Special transportation containers and packaging must be used when moving any radioactive materials.
Every year the BfS calculates the existing quantity of radioactive residual materials and issues figures and forecasts concerning the quantity of waste expected in future.
|
|
Reactor pressure vessel from Rheinsberg nuclear poewr plant: consignment in interim storage facility north (Zwischenlager Nord - ZLN). Source: EWN GmbH (For a larger view, please click on the picture)
|
Long-term interim storage
In the case of decay storage materials are put into interim storage for longer periods of time. The process of radioactive decay means that the activity of these materials gradually decreases. Decay storage is used for dismantled scrap metal, for instance, as well as for large components such as reactor pressure vessels or steam generators. By reducing the activity of these large components, the idea is to enable simplified treatment at a later date while also reducing the quantity of radioactive waste, since once activity has decreased, release may even become a potential option.
The interim storage facility north (Zwischenlager Nord - ZLN) operated by Energiewerke Nord GmbH is used, among other things, as an interim storage facility for the decay storage of radioactive residual materials and waste that occur during plant decommissioning and dismantling.
|
|
Printer safe version
|
|
|
