Abstract
This report summarises nearly 20 biosphere reports and gives a synthesis of the work performed within the SR-Site Biosphere project, i.e. the biosphere part of SR-Site. SR-Site Biosphere provides the main project with dose conversion factors (LDFs), given a unit release rate, for calculation of human doses under different release scenarios, and assesses if a potential release from the repository would have detrimental effects on the environment. The intention of this report is to give sufficient details for an overview of methods, results and major conclusions, with references to the biosphere reports where methods, data and results are presented and discussed in detail. The philosophy of the biosphere assessment was to make estimations of the radiological risk for humans and the environment as realistic as possible, based on the knowledge of present-day conditions at Forsmark and the past and expected future development of the site. This was achieved by using the best available knowledge, understanding and data from extensive site investigations from two sites. When sufficient information was not available, uncertainties were handled cautiously. A systematic identification and evaluation of features and processes that affect transport and accumulation of radionuclides at the site was conducted, and the results were summarised
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Saetre, Peter
[1]
- comp.
Citation Formats
Saetre, Peter.
Biosphere analyses for the safety assessment SR-Site - synthesis and summary of results.
Sweden: N. p.,
2010.
Web.
Saetre, Peter.
Biosphere analyses for the safety assessment SR-Site - synthesis and summary of results.
Sweden.
Saetre, Peter.
2010.
"Biosphere analyses for the safety assessment SR-Site - synthesis and summary of results."
Sweden.
@misc{etde_1013207,
title = {Biosphere analyses for the safety assessment SR-Site - synthesis and summary of results}
author = {Saetre, Peter}
abstractNote = {This report summarises nearly 20 biosphere reports and gives a synthesis of the work performed within the SR-Site Biosphere project, i.e. the biosphere part of SR-Site. SR-Site Biosphere provides the main project with dose conversion factors (LDFs), given a unit release rate, for calculation of human doses under different release scenarios, and assesses if a potential release from the repository would have detrimental effects on the environment. The intention of this report is to give sufficient details for an overview of methods, results and major conclusions, with references to the biosphere reports where methods, data and results are presented and discussed in detail. The philosophy of the biosphere assessment was to make estimations of the radiological risk for humans and the environment as realistic as possible, based on the knowledge of present-day conditions at Forsmark and the past and expected future development of the site. This was achieved by using the best available knowledge, understanding and data from extensive site investigations from two sites. When sufficient information was not available, uncertainties were handled cautiously. A systematic identification and evaluation of features and processes that affect transport and accumulation of radionuclides at the site was conducted, and the results were summarised in an interaction matrix. Data and understanding from the site investigation was an integral part of this work, the interaction matrix underpinned the development of the radionuclide model used in the biosphere assessment. Understanding of the marine, lake and river and terrestrial ecosystems at the site was summarized in a conceptual model, and relevant features and process have been characterized to capture site specific parameter values. Detailed investigations of the structure and history of the regolith at the site and simulations of regolith dynamics were used to describe the present day state at Forsmark and the expected development of the site. The hydrodynamics in the coastal areas was characterized in the field and combined with the bathymetry of the future landscape to forecast the turnover of water in future coastal basins. The surface and near surface hydrology was described at the site and dynamic models were applied on the future landscape to predict vertical and horizontal transport under different climatic conditions. Historical and present human settlement at the site was used to characterize the utilisation of natural resources in a landscape perspective, and the productivity of food items was described and evaluated. The collection and analysis of multi-elemental chemistry data from different environmental media and a wide array of organisms were used to the estimate a unique parameter set describing sorption and biological uptake at the site. A continuous and iterative effort to improve the site characterisation and the site modelling during the investigations resulted in a refined collection of data, in parallel with detailed understanding of the processes that affects transport and accumulation in the surface ecosystems. This interdisciplinary and synchronously large scale collection and analysis of site data makes Forsmark one of the most extensively investigated sites used in risk or environmental assessments. By combining predicted discharge of deep groundwater from the repository and landscape geometries, the areas most likely to be affected by a potential release of radionuclides were identified and outlined, i.e. biosphere objects. The properties and temporal development of these discharge areas were described, developing from a coastal sea basin to a terrestrial ecosystem. The identified biosphere objects represent a considerable variation in size, timing of succession and object-specific properties. An ecosystem-based approach was used to dynamically model transport and accumulation of radionuclides in biosphere objects. The simulations with the model covered a 70,000 year ice free period between two glaciations. The radionuclide model used in SR-Site has been improved in several important ways since previous safety assessments conducted by SKB. For example, the aquatic and terrestrial ecosystems are handled in the same model, which gives a continuous transition from the sea stage to the lake and terrestrial stages. Transport and accumulation in till (lower regolith) is represented in the model. The uptake by plants is included in the mass-balance, and it is related to biomass growth. Moreover, parameter values including hydrological flows, sedimentation and resuspension rates, biomass growth rates, gas exchange rates, as well as element specific distribution coefficients and concentration rations, were as far as possible based on site data. One endpoint from the simulations with the radionuclide model was the landscape dose conversion factors (LDFs).}
place = {Sweden}
year = {2010}
month = {Dec}
}
title = {Biosphere analyses for the safety assessment SR-Site - synthesis and summary of results}
author = {Saetre, Peter}
abstractNote = {This report summarises nearly 20 biosphere reports and gives a synthesis of the work performed within the SR-Site Biosphere project, i.e. the biosphere part of SR-Site. SR-Site Biosphere provides the main project with dose conversion factors (LDFs), given a unit release rate, for calculation of human doses under different release scenarios, and assesses if a potential release from the repository would have detrimental effects on the environment. The intention of this report is to give sufficient details for an overview of methods, results and major conclusions, with references to the biosphere reports where methods, data and results are presented and discussed in detail. The philosophy of the biosphere assessment was to make estimations of the radiological risk for humans and the environment as realistic as possible, based on the knowledge of present-day conditions at Forsmark and the past and expected future development of the site. This was achieved by using the best available knowledge, understanding and data from extensive site investigations from two sites. When sufficient information was not available, uncertainties were handled cautiously. A systematic identification and evaluation of features and processes that affect transport and accumulation of radionuclides at the site was conducted, and the results were summarised in an interaction matrix. Data and understanding from the site investigation was an integral part of this work, the interaction matrix underpinned the development of the radionuclide model used in the biosphere assessment. Understanding of the marine, lake and river and terrestrial ecosystems at the site was summarized in a conceptual model, and relevant features and process have been characterized to capture site specific parameter values. Detailed investigations of the structure and history of the regolith at the site and simulations of regolith dynamics were used to describe the present day state at Forsmark and the expected development of the site. The hydrodynamics in the coastal areas was characterized in the field and combined with the bathymetry of the future landscape to forecast the turnover of water in future coastal basins. The surface and near surface hydrology was described at the site and dynamic models were applied on the future landscape to predict vertical and horizontal transport under different climatic conditions. Historical and present human settlement at the site was used to characterize the utilisation of natural resources in a landscape perspective, and the productivity of food items was described and evaluated. The collection and analysis of multi-elemental chemistry data from different environmental media and a wide array of organisms were used to the estimate a unique parameter set describing sorption and biological uptake at the site. A continuous and iterative effort to improve the site characterisation and the site modelling during the investigations resulted in a refined collection of data, in parallel with detailed understanding of the processes that affects transport and accumulation in the surface ecosystems. This interdisciplinary and synchronously large scale collection and analysis of site data makes Forsmark one of the most extensively investigated sites used in risk or environmental assessments. By combining predicted discharge of deep groundwater from the repository and landscape geometries, the areas most likely to be affected by a potential release of radionuclides were identified and outlined, i.e. biosphere objects. The properties and temporal development of these discharge areas were described, developing from a coastal sea basin to a terrestrial ecosystem. The identified biosphere objects represent a considerable variation in size, timing of succession and object-specific properties. An ecosystem-based approach was used to dynamically model transport and accumulation of radionuclides in biosphere objects. The simulations with the model covered a 70,000 year ice free period between two glaciations. The radionuclide model used in SR-Site has been improved in several important ways since previous safety assessments conducted by SKB. For example, the aquatic and terrestrial ecosystems are handled in the same model, which gives a continuous transition from the sea stage to the lake and terrestrial stages. Transport and accumulation in till (lower regolith) is represented in the model. The uptake by plants is included in the mass-balance, and it is related to biomass growth. Moreover, parameter values including hydrological flows, sedimentation and resuspension rates, biomass growth rates, gas exchange rates, as well as element specific distribution coefficients and concentration rations, were as far as possible based on site data. One endpoint from the simulations with the radionuclide model was the landscape dose conversion factors (LDFs).}
place = {Sweden}
year = {2010}
month = {Dec}
}