Biosphere Parameters Used in Radionuclide Transport Modelling and Dose Calculations in SR-PSU
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R-13-18 Biosphere parameters used in radionuclide transport modelling and dose calculations in SR-PSU Sara Grolander, Sara Grolander Miljökonsult AB December 2013 Svensk Kärnbränslehantering AB Swedish Nuclear Fuel and Waste Management Co Box 250, SE-101 24 Stockholm Phone +46 8 459 84 00 ISSN 1402-3091 Tänd ett lager: SKB R-13-18 P, R eller TR. ID 1425906 December 2013 Updated 2016-10 Biosphere parameters used in radionuclide transport modelling and dose calculations in SR-PSU Sara Grolander, Sara Grolander Miljökonsult AB This report concerns a study which was conducted for Svensk Kärnbränslehantering AB (SKB). The conclusions and viewpoints presented in the report are those of the author. SKB may draw modified conclusions, based on additional literature sources and/or expert opinions. A pdf version of this document can be downloaded from www.skb.se. © 2015 Svensk Kärnbränslehantering AB Update notice The original report, dated December 2013, was found to contain both factual and editorial errors which have been corrected in this updated version. The corrected factual errors are presented below. Updated 2016-10 Location Original text Corrected text Page 54, first paragraph, last “The water flows derived from the MIKE “The water flows derived from the sentence SHE simulation with a wetter and warmer MIKE SHE simulation with a wetter climate are used to parameterise the water and warmer climate are used to flows in the global warming climate case in parameterise the water flows in the the radionuclide model.” extended global warming climate case in the radionuclide model.“ Page 134, Table 12-1 and Table Well id 12 Well id 29 12-2, first column, second row Abstract This report is produced within the biosphere part of the safety assessment SR-PSU and describes all biosphere parameters used in the radionuclide model for the biosphere. The report consists of several chapters where different parameter types are decribed (Chapter 3 – Radionuclide specific parameters, Chapter 4 – Landscape geometries, Chapter 5 – Regolith characteristics, Chapter 6 – Hydrological parameters, Chapter 7 – Element specific parameters, Chapter 8 – Aquatic ecosystem parameters, Chapter 9 – Terrestrial ecosystem parameters, Chapter 10 – Human characteristics, Chapter 11 – Non-human biota parameters, Chapter 12 – Parameters used in alternative calculation cases). Chapter 1 givs a general introduction to the SR-PSU safety assessment and Chapter 2 pre- sents the conditions for parameterisation and the general assumption made in the parameterisation process. SKB R-13-18 3 Sammanfattning Den här rapporten är en underlagsrapport till biosfärsdelen av säkerhetsanalysen SR-PSU och samman ställer alla parametrar som använts i radionuklidmodelleringen för biosfären. Rapporten består av kapitel där olika parametergrupper presenteras och beskrivs i detalj (kapitel 3 – radionuklid - specifika parametrar, kapitel 4 – landskapsparametrar, kapitel 5 – regolitparametrar, kapitel 6 – hydro- logiska parametrar, kapitel 7 – ämnesspecifika parametrar, kapitel 8 – akvatiska ekosystemparametrar, kapitel 9 – terestra ekosystemparametrar, kapitel 10 – parametrar som beskriver människan, kapitel 11 – parametrar som beskriver biota (annan än människan), kapitel 12 – parametrar som används i alternativa beräkningsfall i SR-PSU). Kapitel 1 ger en introduktion till säkerhetsanalysen SR-PSU och beskriver den här rapportens roll i arbetet. I kapitel 2 finns en beskrivning av de förutsättningar och antaganden som ligger till grund för parameteriseringsarbetet. 4 SKB R-13-18 Contents 1 Introduction 9 1.1 The SR-PSU report hierarchy 11 1.2 This report 13 2 Conditions for parameterisation 15 2.1 Radionuclide transport model 15 2.2 Landscape development and biosphere objects 16 2.3 Human inhabitants 17 2.4 Climate cases 18 2.5 Additional calculation cases 20 2.6 Selecting parameter values and probability density functions 20 3 Radionuclide-specific parameters 23 3.1 Experience from previous safety assessments 24 3.2 Influence of climate on parameter values 24 3.3 Handling of the dose contribution of progeny in decay chains 24 3.4 Radionuclide-specific dose coefficients 29 3.4.1 Exposure to contaminated air following the combustion of peat or wood 33 3.4.2 Exposure to progeny radionuclides in agricultural lands 34 4 Landscape geometries 35 4.1 Experience from previous safety assessments 35 4.2 Influence of climate on parameter values 35 4.3 Parameters describing developmental stages of the biosphere object 36 4.3.1 Time at which lake isolation starts 36 4.3.2 Time of complete isolation 36 4.3.3 Time when it is possible to use a well 37 4.3.4 Time of isolation 37 4.3.5 Time when land areas start to appear in the object 37 4.3.6 Time when the whole biosphere object is turned into a wetland 37 4.4 Parameters describing biosphere object geometries 37 4.4.1 Total size of biosphere objects after isolation from the sea 37 4.4.2 Surface area of the aquatic part of each biosphere object 38 4.4.3 Surface area of the terrestrial part of the biosphere objects 38 4.4.4 Average depth of water 38 4.4.5 Thickness of glacial till layer 38 4.4.6 Thickness of the glacial clay layer 39 4.4.7 Thickness of the postglacial gyttja clay in lakes 39 4.4.8 Thickness of post glacial gyttja in wetlands 39 4.4.9 Thickness of anoxic peat 39 4.4.10 Illustration of time-dependent parameters 40 4.5 Parameters related to sedimentation, resuspension and lake infilling 41 4.5.1 Resuspension rate 41 4.5.2 Sedimentation rate 41 4.5.3 Ingrowth of peat 41 4.6 Parameters for object 114 41 4.7 Parameters for object 1 and 10 42 5 Regolith characteristics 43 5.1 Experience from previous safety assessments 43 5.2 Influence of climate on parameter values 43 5.3 Density and porosity of non-cultivated soils 44 5.3.1 Density and porosity of till 44 5.3.2 Density and porosity of glacial clay 44 5.3.3 Density and porosity of postglacial clay gyttja 45 SKB R-13-18 5 5.3.4 Density and porosity of anoxic peat 45 5.3.5 Density and porosity of oxic peat 46 5.3.6 Porosity and density of aquatic sediments 46 5.4 Properties of cultivated soils 47 5.4.1 Density and porosity of peat and clay gyttja in a cultivated wetland 47 5.4.2 Density and porosity of cultivated glacial clay 48 5.4.3 Degree of compaction of clay gyttja and peat in a drained mire 48 5.4.4 Pore water content of agricultural soils 49 5.4.5 Diffusivity of CO2 in soil 50 6 Hydrological parameters 53 6.1 Experience from previous safety assessments 53 6.2 Influence of climate on parameter values 53 6.3 Inter-basin water exchange in marine areas 54 6.4 Inter-compartment water fluxes in marine, limnic and terrestrial ecosystems 55 7 Element-specific parameters 59 7.1 Experience from previous safety assessments 59 7.2 Influence of climate on parameter values 59 7.3 Soil/liquid partitioning coefficient, Kd 60 7.4 Concentration ratios 60 7.5 Diffusivity in free solution 62 8 Aquatic ecosystem parameters 63 8.1 Experience from previous safety assessments 63 8.2 Influence of climate on parameter values 63 8.3 Assumptions for limnic ecosystems 64 8.4 Assumptions for marine ecosystem 65 8.5 Particulate matter and dissolved inorganic carbon 65 8.5.1 Particulate matter 65 8.5.2 Dissolved inorganic carbon 66 8.6 Biomass and production of primary producers 67 8.6.1 Parameters affecting biomass and production of primary producers 67 8.6.2 Biomass 69 8.6.3 Net primary production 72 8.7 Decomposition and mineralisation 76 8.7.1 Thickness of oxidising upper regolith layer 76 8.7.2 Refractory organic carbon 76 8.7.3 Mineralisation rate 78 8.8 Gas exchange across the air-water interface 80 8.8.1 Piston velocity 80 8.8.2 Fraction of total DIC present as CO2 82 8.8.3 Solubility of CO2 at equilibrium 83 8.8.4 Wind speed, pH, salinity, temperature, and Schmidt number 84 8.9 Aquatic atmosphere parameters 86 8.10 Human food parameters 87 8.10.1 Fish production 87 8.10.2 Production of crayfish 89 9 Terrestrial ecosystem parameters 91 9.1 Experience from previous safety assessments 91 9.2 Influence of climate on parameter values 91 9.3 Biomass and net primary production for a mire 92 9.4 Carbon in the mire ecosystem 94 9.4.1 Dissolved inorganic carbon in pore water 94 9.4.2 Fraction of total DIC present as CO2 in peat pore water 95 9.4.3 Carbon content of peat 96 9.4.4 Carbon root uptake by vascular plants 96 9.4.5 Piston velocity 97 9.4.6 Solubility of CO2 at equilibrium 98 6 SKB R-13-18 9.5 Terrestrial atmosphere parameters 99 9.5.1 Drag coefficient 99 9.5.2 Height of the terrestrial Layer 1 100 9.5.3 Height of the terrestrial Layer 2 100 9.5.4 Kármán constant 100 9.5.5 Leaf width 100 9.5.6 Leaf area index 100 9.5.7 Concentration of carbon in the atmosphere 102 9.5.8 Wind velocity 102 9.5.9 Vegetation height 103 9.6 Fluxes of chlorine in ecosystems 103 9.6.1 Concentration of chlorine in mire vegetation 103 9.6.2 Concentration of dissolved chlorine in the mire pore water 103 9.6.3 Discrimination factor during decomposition for chlorine 104 9.7 Depth of biological active layer of peat and cultivated peat 104 9.8 Hydrological fluxes in agricultural soil 105 9.8.1 Percolation in areas used for cultivation 105 9.8.2 Upward flux of groundwater into the unsaturated zone of the agricultural land 106 9.9 Mineralisation 107 9.9.1 Mineralisation rate in different layers and ecosystems 107 9.9.2 Mineralisation rate in the anoxic peat layer at equilibrium 110 9.10 Dust concentration 111 9.11 Crop yields 112 9.12 Production of berries, mushroom and game 114 9.12.1 Production of berries 114 9.12.2 Production of game 115