This Technical Note describes the development of simple reference biosphere models as a means of exploring the Landscape Dose Factor (LDF) approach adopted by SKB in the SR-Site safety assessment for the proposed final disposal of spent nuclear fuel at the Forsmark site. The models are developed and described in a systematic manner, based on international guidance reflected in the International Atomic Energy Agency’s BIOMASS approach.
The context for the modelling is described and SR-Site documentation is used to provide a description of the current biosphere and land uses at Forsmark. This information is used to justify development of biosphere models to represent potential future radionuclide releases to marine, lake, mire, forest, pasture and arable systems from the repository. A simple modelling approach is adopted, so, unlike the SR-Site safety assessment, the systems are modelled independently and the succession between the biosphere systems, which is driven by land rise resulting from isostatic post-glacial rebound, is not represented.