Environmental impacts of decommissioning nuclear power plants: methodical challenges, case study, and implications

Environmental impacts of the decommissioning of nuclear power plants are brought into focus by the nuclear phase-out in Germany and a worldwide growing number of decommissioning projects. So far, life cycle assessments of decommissioning nuclear power plants have been conducted very rarely or are based on rather uncertain assumptions. Against this background, environmental impacts of the ongoing decommissioning of the nuclear power plant in Lubmin (KGR), Germany are examined. Methodological aspects like transferability to other decommissioning projects as well as influence of assumptions about the lifespan of a power plant are discussed.

A life cycle assessment of the decommissioning according to ISO 14040/44 is conducted. The decommissioning of one power plant (of the assessed KGR) is chosen as functional unit. The system boundaries include removal and demolition of plant components and buildings as well as decontamination, conditioning, interim storage, and final repository of low-level and interim-level nuclear waste together with disposal and recycling of conventional waste. Interim storage and final repository of high-level nuclear waste such as fuel rods are excluded from the system boundaries as they are assigned to the use phase of the plant. Primary data was obtained from the plant decommissioning firm (Energiewerke Nord GmbH, EWN) in Lubmin. The GaBi database was used to model background processes. Environmental impacts are estimated using the CML2001 methodology.

Environmental impacts are mainly caused by on-site energetic demands of component removal and peripheral tasks. Further significant impacts are caused by the handling, storage, and final repository of low-level and intermediate-level nuclear waste. Recycling conventional, nonradioactive metallic waste has the potential to unburden the process in a significant scale, depending on recycling rates.

The dismantling of nuclear power plants shows a relevant environmental impact. Regarding the environmental impacts per kilowatt-hour assumptions concerning the plant’ lifespan are a crucial factor. Comparing the result from this study to recent datasets for nuclear power poses the question if LCA datasets represent environmental burdens of nuclear power accurately.

The transferability of LCA results to other studies using one parameter for scaling is problematic and needs further research.